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• asyncore callbacks launching threads... ok to do?

  - by sbartell

  I'm unfamiliar with asyncore, and have very limited knowledge of asynchronous programming except for a few intro to twisted tutorials. I am most familiar with threads and use them in all my apps. One particular app uses a couchdb database as its interface. This involves longpolling the db looking for changes and updates. The module I use for couchdb is couchdbkit. It uses an asyncore loop to watch for these changes and send them to a callback. So, I figure from this callback is where I launch my worker threads. It seems a bit crude to mix asynchronous and threaded programming. I really like couchdbkit, but would rather not introduce issues into my program. So, my question is, is it safe to fire threads from an async callback? Here's some code... {{{ def dispatch(change): global jobs, db_url # jobs is my queue db = Database(db_url) work_order = db.get(change['id']) # change is an id to the document that changed. # i need to get the actual document (workorder) worker = Worker(work_order, db) # fire the thread jobs.append[worker] worker.start() return main() . . . consumer.wait(cb=dispatch, since=update_seq, timeout=10000) #wait constains the asyncloop. }}}

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• Simple continuously running XMPP client in python

  - by tom

  I'm using python-xmpp to send jabber messages. Everything works fine except that every time I want to send messages (every 15 minutes) I need to reconnect to the jabber server, and in the meantime the sending client is offline and cannot receive messages. So I want to write a really simple, indefinitely running xmpp client, that is online the whole time and can send (and receive) messages when required. My trivial (non-working) approach: import time import xmpp class Jabber(object): def __init__(self): server = 'example.com' username = 'bot' passwd = 'password' self.client = xmpp.Client(server) self.client.connect(server=(server, 5222)) self.client.auth(username, passwd, 'bot') self.client.sendInitPresence() self.sleep() def sleep(self): self.awake = False delay = 1 while not self.awake: time.sleep(delay) def wake(self): self.awake = True def auth(self, jid): self.client.getRoster().Authorize(jid) self.sleep() def send(self, jid, msg): message = xmpp.Message(jid, msg) message.setAttr('type', 'chat') self.client.send(message) self.sleep() if __name__ == '__main__': j = Jabber() time.sleep(3) j.wake() j.send('[email protected]', 'hello world') time.sleep(30) The problem here seems to be that I cannot wake it up. My best guess is that I need some kind of concurrency. Is that true, and if so how would I best go about that? EDIT: After looking into all the options concerning concurrency, I decided to go with twisted and wokkel. If I could, I would delete this post.

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• Python's asyncore to periodically send data using a variable timeout. Is there a better way?

  - by Nick Sonneveld

  I wanted to write a server that a client could connect to and receive periodic updates without having to poll. The problem I have experienced with asyncore is that if you do not return true when dispatcher.writable() is called, you have to wait until after the asyncore.loop has timed out (default is 30s). The two ways I have tried to work around this is 1) reduce timeout to a low value or 2) query connections for when they will next update and generate an adequate timeout value. However if you refer to 'Select Law' in 'man 2 select_tut', it states, "You should always try to use select() without a timeout." Is there a better way to do this? Twisted maybe? I wanted to try and avoid extra threads. I'll include the variable timeout example here: #!/usr/bin/python import time import socket import asyncore # in seconds UPDATE_PERIOD = 4.0 class Channel(asyncore.dispatcher): def __init__(self, sock, sck_map): asyncore.dispatcher.__init__(self, sock=sock, map=sck_map) self.last_update = 0.0 # should update immediately self.send_buf = '' self.recv_buf = '' def writable(self): return len(self.send_buf) > 0 def handle_write(self): nbytes = self.send(self.send_buf) self.send_buf = self.send_buf[nbytes:] def handle_read(self): print 'read' print 'recv:', self.recv(4096) def handle_close(self): print 'close' self.close() # added for variable timeout def update(self): if time.time() >= self.next_update(): self.send_buf += 'hello %f\n'%(time.time()) self.last_update = time.time() def next_update(self): return self.last_update + UPDATE_PERIOD class Server(asyncore.dispatcher): def __init__(self, port, sck_map): asyncore.dispatcher.__init__(self, map=sck_map) self.port = port self.sck_map = sck_map self.create_socket(socket.AF_INET, socket.SOCK_STREAM) self.bind( ("", port)) self.listen(16) print "listening on port", self.port def handle_accept(self): (conn, addr) = self.accept() Channel(sock=conn, sck_map=self.sck_map) # added for variable timeout def update(self): pass def next_update(self): return None sck_map = {} server = Server(9090, sck_map) while True: next_update = time.time() + 30.0 for c in sck_map.values(): c.update() # <-- fill write buffers n = c.next_update() #print 'n:',n if n is not None: next_update = min(next_update, n) _timeout = max(0.1, next_update - time.time()) asyncore.loop(timeout=_timeout, count=1, map=sck_map)

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• Reasonably faster way to traverse a directory tree in Python?

  - by Sridhar Ratnakumar

  Assuming that the given directory tree is of reasonable size: say an open source project like Twisted or Python, what is the fastest way to traverse and iterate over the absolute path of all files/directories inside that directory? I want to do this from within Python (subprocess is allowed). os.path.walk is slow. So I tried ls -lR and tree -fi. For a project with about 8337 files (including tmp, pyc, test, .svn files): $ time tree -fi > /dev/null real 0m0.170s user 0m0.044s sys 0m0.123s $ time ls -lR > /dev/null real 0m0.292s user 0m0.138s sys 0m0.152s $ time find . > /dev/null real 0m0.074s user 0m0.017s sys 0m0.056s $ tree appears to be faster than ls -lR (though ls -R is faster than tree, but it does not give full paths). find is the fastest. Can anyone think of a faster and/or better approach? On Windows, I may simply ship a 32-bit binary tree.exe or ls.exe if necessary. Update 1: Added find

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• Advice: Python Framework Server/Worker Queue management (not Website)

  - by Muppet Geoff

  I am looking for some advice/opinions of which Python Framework to use in an implementation of multiple 'Worker' PCs co-ordinated from a central Queue Manager. For completeness, the 'Worker' PCs will be running Audio Conversion routines (which I do not need advice on, and have standalone code that works). The Audio conversion takes a long time, and I need to co-ordinate an arbitrary number of the 'Workers' from a central location, handing them conversion tasks (such as where to get the source files, or where to ask for the job configuration) with them reporting back some additional info, such as the runtime of the converted audio etc. At present, I have a script that makes a webservice call to get the 'configuration' for a conversion task, based on source files located on the worker already (we manually copy the source files to the worker, and that triggers a conversion routine). I want to change this, so that we can distribute conversion tasks ("Oy you, process this: xxx") based on availability, and in an ideal world, based on pending tasks too. There is a chance that Workers can go offline mid-conversion (but this is not likely). All the workers are Windows based, the co-ordinator can be WIndows or Linux. I have (in my initial searches) come across the following - and I know that some are cross-dependent: Celery (with RabbitMQ) Twisted Django Using a framework, rather than home-brewing, seems to make more sense to me right now. I have a limited timeframe in which to develop this functional extension. An additional consideration would be using a Framework that is compatible with PyQT/PySide so that I can write a simple UI to display Queue status etc. I appreciate that the specifics above are a little vague, and I hope that someone can offer me a pointer or two. Again: I am looking for general advice on which Python framework to investigate further, for developing a Server/Worker 'Queue management' solution, for non-web activities (this is why DJango didn't seem the right fit).

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• Communicating with a running python daemon

  - by hanksims

  I wrote a small Python application that runs as a daemon. It utilizes threading and queues. I'm looking for general approaches to altering this application so that I can communicate with it while it's running. Mostly I'd like to be able to monitor its health. In a nutshell, I'd like to be able to do something like this: python application.py start # launches the daemon Later, I'd like to be able to come along and do something like: python application.py check_queue_size # return info from the daemonized process To be clear, I don't have any problem implementing the Django-inspired syntax. What I don't have any idea how to do is to send signals to the daemonized process (start), or how to write the daemon to handle and respond to such signals. Like I said above, I'm looking for general approaches. The only one I can see right now is telling the daemon constantly log everything that might be needed to a file, but I hope there's a less messy way to go about it. UPDATE: Wow, a lot of great answers. Thanks so much. I think I'll look at both Pyro and the web.py/Werkzeug approaches, since Twisted is a little more than I want to bite off at this point. The next conceptual challenge, I suppose, is how to go about talking to my worker threads without hanging them up. Thanks again.

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• What am I doing wrong with SVN merging?

  - by randomusername

  When SVN with merge tracking works, it's really nice, I love it. But it keeps getting twisted up. We are using TortoiseSVN. We continuously get the following message: Error: Reintegrate can only be used if revisions 1234 through 2345 were previously merged from /Trunk to the reintegrate source, but this is not the case For reference, this is the method we are using: Create a Branch Develop in the branch Occasionally Merge a range of revisions from the Trunk to the Branch When branch is stable, Reintegrate a branch from the branch to the trunk Delete the branch I Merge a range of revisions from the trunk to the branch (leaving the range blank, so it should be all revisions) just prior to the reintegrate operation, so the branch should be properly synced with the trunk. Right now, the Trunk has multiple SVN merge tracking properties associated with it. Should it? Or should a Reintegrate not add any merge tracking info? Is there something wrong with our process? This is making SVN unusable - 1 out of every 3 reintegrates forces me to dive in and hack at the merge tracking info.

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• udp expected behaviour not responding to test result

  - by ernst

  I have a local network topology that is structured as follows: three hosts and a switch in the middle. I am using a switch that supports 10,100,1000 Mbit/s full/half duplex connection. I have configured the hosts with a static ip 172.16.0.1-2-3/25. This is the output of ifconfig eth0 Link encap: Ethernet HWaddr ***** inet addr:172.16.0.3 Bcast:172.16.0.127 Mask:255.255.255.128 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:16 The output on H1 and H2 is perfectly matchable They are mutually reachable since i have tested the network with ping. I have forced the ethernet interface to work at 10M with ethtool -s eth0 speed 10 duplex full autoneg on this is the output of ethtool eth0 supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full S upported pause frame use: No Supports auto-negotiation: Yes Advertised link modes: 10baseT/Full Advertised pause frame use: Symmetric A dvertised auto-negotiation: Yes Speed: 10Mb/s Duplex: Full Port: Twisted Pair PHYAD: 1 Transceiver: internal Auto-negotiation: on MDI-X: Unknown Supports Wake-on: g Wake-on: d Current message level: 0x000000ff (255) drv probe link timer ifdown ifup rx_err tx_err Link detected: yes – I am doing an experimental test using nttcp to calculate the GOODPUT in the case that H1 and H2 at the same time send data to H3. Since the three links have the same forced capability and the amount of arrving data speed is 10 from H1+10 from H2--20M to H3 it would be expected a bottleneck effect and, due to the non reliable nature of udp, a packet loss. But this doesn't appen since the output of nttcp application shows the same number of byte sended and received. this is the output of nttcp on h3 nttcp -T -r -u 172.16.0.2 & nttcp -T -r -u 172.16.0.1 [1] 4071 Bytes Real s CPU s Real-MBit/s CPU-MBit/s Calls Real-C/s CPU-C/s l 8388608 13.74 0.05 4.8848 1398.0140 2049 149.14 42684.8 Bytes Real s CPU s Real-MBit/s CPU-MBit/s Calls Real-C/s CPU-C/s l 8388608 14.02 0.05 4.7872 1398.0140 2049 146.17 42684.8 1 8388608 13.56 0.06 4.9500 1118.4065 2051 151.28 34181.1 1 8388608 13.89 0.06 4.8310 1198.3084 2051 147.65 36623.0 – How is this possible? Am i missing something? Any help will be gratefully apprecciated, Best regards

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• load-causing processes disappearing from "top" ps -o pcpu shows bogus numbers

  - by Alec Matusis

  I administer a large number of servers, and I have this problem only with Ubuntu 10.04 LTS: I run a server under normal load (say load average 3.0 on an 8-core server). The "top" command shows processes taking certain % of CPU that cause this load average: say PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 11008 mysql 20 0 25.9g 22g 5496 S 67 76.0 643539:38 mysqld ps -o pcpu,pid -p11008 %CPU PID 53.1 11008 , everything is consistent. The all of the sudden, the process causing the load average disappears from "top", but the process continues to run normally (albeit with a slight performance decrease), and the system load average becomes somewhat higher. The output of ps -o pcpu becomes bogus: # ps -o pcpu,pid -p11008 %CPU PID 317910278 1587 This happened to at least 5 different severs (different brand new IBM System X hardware), each running different software: one httpd 2.2, one mysqld 5.1, and one Twisted Python TCP servers. Each time the kernel was between 2.6.32-32-server and 2.6.32-40-server. I updated some machines to 2.6.32-41-server, and it has not happened on those yet, but the bug is rare (once every 60 days or so). This is from an affected machine: top - 10:39:06 up 73 days, 17:57, 3 users, load average: 6.62, 5.60, 5.34 Tasks: 207 total, 2 running, 205 sleeping, 0 stopped, 0 zombie Cpu(s): 11.4%us, 18.0%sy, 0.0%ni, 66.3%id, 4.3%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 74341464k total, 71985004k used, 2356460k free, 236456k buffers Swap: 3906552k total, 328k used, 3906224k free, 24838212k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 805 root 20 0 0 0 0 S 3 0.0 1493:09 fct0-worker 982 root 20 0 0 0 0 S 1 0.0 111:35.05 fioa-data-groom 914 root 20 0 0 0 0 S 0 0.0 884:42.71 fct1-worker 1068 root 20 0 19364 1496 1060 R 0 0.0 0:00.02 top Nothing causing high load is showing on top, but I have two highly loaded mysqld instances on it, that suddenly show crazy %CPU: #ps -o pcpu,pid,cmd -p1587 %CPU PID CMD 317713124 1587 /nail/encap/mysql-5.1.60/libexec/mysqld and #ps -o pcpu,pid,cmd -p1624 %CPU PID CMD 2802 1624 /nail/encap/mysql-5.1.60/libexec/mysqld Here are the numbers from # cat /proc/1587/stat 1587 (mysqld) S 1212 1088 1088 0 -1 4202752 14307313 0 162 0 85773299069 4611685932654088833 0 0 20 0 52 0 3549 27255418880 5483524 18446744073709551615 4194304 11111617 140733749236976 140733749235984 8858659 0 552967 4102 26345 18446744073709551615 0 0 17 5 0 0 0 0 0 the 14th and 15th numbers according to man proc are supposed to be utime %lu Amount of time that this process has been scheduled in user mode, measured in clock ticks (divide by sysconf(_SC_CLK_TCK). This includes guest time, guest_time (time spent running a virtual CPU, see below), so that applications that are not aware of the guest time field do not lose that time from their calculations. stime %lu Amount of time that this process has been scheduled in kernel mode, measured in clock ticks (divide by sysconf(_SC_CLK_TCK). On a normal server, these numbers are advancing, every time I check the /proc/PID/stat. On a buggy server, these numbers are stuck at a ridiculously high value like 4611685932654088833, and it's not changing. Has anyone encountered this bug?

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• NIC is receiving, but not transmitting at all?

  - by Shtééf

  I'm trying to fix a very strange problem remotely on a machine at a customer site. The machine is a Dell PowerEdge, I believe a 1950 (haven't verified, but the lspci output matches specs I found.) The machine has two similar NICs, identified as Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet (rev 12) by lspci, and using the bnx2 driver. (I suspect these are on-board and on the same controller, which is what I'm accustomed to for this type of machine.) The primary interface eth0 works perfectly, and is in fact how I am ssh'd in. However, the secondary interface eth1 is not transmitting. I can see this in ifconfig output, for example, where the TX field is always 0. However, it is receiving, and tcpdump shows ARP requests coming from the ISP's gateway on the other side. The interface is physically connected to a Siemens BSTU4 modem, configured by the ISP. The link is properly set to 10MBps and full duplex, without negotation, as the ISP requested. A small /30 subnet is configured. For the sake of anonimity, let's say the machine is 3.3.3.2/30, and the ISP's gateway .1. The machine has no firewall settings whatsoever. Even running something like arping -I eth1 3.3.3.1, and running tcpdump alongside, shows no traffic whatsoever being transmitted on the interface. (But the other side keeps steadily sending ARP requests, and that is all that can be seen.) What could be causing this? Here's some output, anonymized, which may hopefully help: $ ethtool eth1 Settings for eth1: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supports auto-negotiation: Yes Advertised link modes: Not reported Advertised auto-negotiation: No Speed: 10Mb/s Duplex: Full Port: Twisted Pair PHYAD: 1 Transceiver: internal Auto-negotiation: off Supports Wake-on: d Wake-on: d Link detected: yes $ ip link show eth1 3: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:15:c5:xx:xx:xx brd ff:ff:ff:ff:ff:ff $ ip -4 addr show eth1 3: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000 inet 3.3.3.2/30 brd 3.3.3.3 scope global eth1 $ ip -4 route show match 3.3.3.0/30 3.3.3.0/30 dev eth1 proto kernel scope link src 3.3.3.2 default via 10.0.0.5 dev eth0

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• Network unreachable on Ubuntu guest after trying to set up a host only network on Virtualbox

  - by gkb0986

  I have a Mac OS X host and a bunch of guests including Ubuntu and Arch Linux. I was trying to set up a host-only network at eth1 to let me ssh into the system. But now eth0 isn't working properly either. Ubuntu can no longer connect to remote hosts or browse the internet. It tells me that the network is unreachable. What's gone wrong here? I've included some diagnostics below. $ifconfig lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:10968 errors:0 dropped:0 overruns:0 frame:0 TX packets:10968 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:897264 (897.2 KB) TX bytes:897264 (897.2 KB) Other diagnostic commands and the output: $sudo lspci -n 00:00.0 0600: 8086:1237 (rev 02) 00:01.0 0601: 8086:7000 00:01.1 0101: 8086:7111 (rev 01) 00:02.0 0300: 80ee:beef 00:03.0 0200: 8086:100e (rev 02) 00:04.0 0880: 80ee:cafe 00:05.0 0401: 8086:2415 (rev 01) 00:06.0 0C03: 106B:003F 00:07.0 0680: 8086:7113 (REV 08) 00:0D.0 0106: 8086:2829 (REV 02) $sudo lshw -c network *-network DISABLED description: Ethernet interface product: 82540EM Gigabit Ethernet Controller vendor: Intel Corporation physical id: 3 bus info: pci@0000:00:03.0 logical name: eth0 version: 02 serial: 08:00:27:7d:22:df size: 1Gbit/s capacity: 1Gbit/s width: 32 bits clock: 66MHz capabilities: pm pcix bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e1000 driverversion=7.3.21-k8-NAPI duplex=full firmware=N/A latency=64 link=no mingnt=255 multicast=yes port=twisted pair speed=1Gbit/s resources: irq:19 memory:f0000000-f001ffff ioport:d010(size=8) $lsmod Module Size Used by nls_utf8 12557 1 isofs 40257 1 vboxsf 43743 2 vesafb 13844 1 snd_intel8x0 38570 2 snd_ac97_codec 134869 1 snd_intel8x0 ac97_bus 12730 1 snd_ac97_codec snd_pcm 97275 2 snd_intel8x0,snd_ac97_codec snd_seq_midi 13324 0 snd_rawmidi 30748 1 snd_seq_midi snd_seq_midi_event 14899 1 snd_seq_midi rfcomm 47604 0 snd_seq 61929 2 snd_seq_midi,snd_seq_midi_event bnep 18281 2 bluetooth 180113 10 rfcomm,bnep ppdev 17113 0 psmouse 97519 0 snd_timer 29990 2 snd_pcm,snd_seq joydev 17693 0 snd_seq_device 14540 3 snd_seq_midi,snd_rawmidi,snd_seq vboxvideo 12622 1 serio_raw 13211 0 snd 79041 11 snd_intel8x0,snd_ac97_codec,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device soundcore 15091 1 snd vboxguest 235498 7 vboxsf parport_pc 32866 0 drm 241971 2 vboxvideo i2c_piix4 13301 0 snd_page_alloc 18529 2 snd_intel8x0,snd_pcm mac_hid 13253 0 lp 17799 0 parport 46562 3 ppdev,parport_pc,lp usbhid 47238 0 hid 99636 1 usbhid e1000 108589 0

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• Breaking through the class sealing

  - by Jason Crease

  Do you understand 'sealing' in C#?  Somewhat?  Anyway, here's the lowdown. I've done this article from a C# perspective, but I've occasionally referenced .NET when appropriate. What is sealing a class? By sealing a class in C#, you ensure that you ensure that no class can be derived from that class.  You do this by simply adding the word 'sealed' to a class definition: public sealed class Dog {} Now writing something like " public sealed class Hamster: Dog {} " you'll get a compile error like this: 'Hamster: cannot derive from sealed type 'Dog' If you look in an IL disassembler, you'll see a definition like this: .class public auto ansi sealed beforefieldinit Dog extends [mscorlib]System.Object Note the addition of the word 'sealed'. What about sealing methods? You can also seal overriding methods.  By adding the word 'sealed', you ensure that the method cannot be overridden in a derived class.  Consider the following code: public class Dog : Mammal { public sealed override void Go() { } } public class Mammal { public virtual void Go() { } } In this code, the method 'Go' in Dog is sealed.  It cannot be overridden in a subclass.  Writing this would cause a compile error: public class Dachshund : Dog { public override void Go() { } } However, we can 'new' a method with the same name.  This is essentially a new method; distinct from the 'Go' in the subclass: public class Terrier : Dog { public new void Go() { } } Sealing properties? You can also seal seal properties.  You add 'sealed' to the property definition, like so: public sealed override string Name {     get { return m_Name; }     set { m_Name = value; } } In C#, you can only seal a property, not the underlying setters/getters.  This is because C# offers no override syntax for setters or getters.  However, in underlying IL you seal the setter and getter methods individually - a property is just metadata. Why bother sealing? There are a few traditional reasons to seal: Invariance. Other people may want to derive from your class, even though your implementation may make successful derivation near-impossible.  There may be twisted, hacky logic that could never be second-guessed by another developer.  By sealing your class, you're protecting them from wasting their time.  The CLR team has sealed most of the framework classes, and I assume they did this for this reason. Security.  By deriving from your type, an attacker may gain access to functionality that enables him to hack your system.  I consider this a very weak security precaution. Speed.  If a class is sealed, then .NET doesn't need to consult the virtual-function-call table to find the actual type, since it knows that no derived type can exist.  Therefore, it could emit a 'call' instead of 'callvirt' or at least optimise the machine code, thus producing a performance benefit.  But I've done trials, and have been unable to demonstrate this If you have an example, please share! All in all, I'm not convinced that sealing is interesting or important.  Anyway, moving-on... What is automatically sealed? Value types and structs.  If they were not always sealed, all sorts of things would go wrong.  For instance, structs are laid-out inline within a class.  But what if you assigned a substruct to a struct field of that class?  There may be too many fields to fit. Static classes.  Static classes exist in C# but not .NET.  The C# compiler compiles a static class into an 'abstract sealed' class.  So static classes are already sealed in C#. Enumerations.  The CLR does not track the types of enumerations - it treats them as simple value types.  Hence, polymorphism would not work. What cannot be sealed? Interfaces.  Interfaces exist to be implemented, so sealing to prevent implementation is dumb.  But what if you could prevent interfaces from being extended (i.e. ban declarations like "public interface IMyInterface : ISealedInterface")?  There is no good reason to seal an interface like this.  Sealing finalizes behaviour, but interfaces have no intrinsic behaviour to finalize Abstract classes.  In IL you can create an abstract sealed class.  But C# syntax for this already exists - declaring a class as a 'static', so it forces you to declare it as such. Non-override methods.  If a method isn't declared as override it cannot be overridden, so sealing would make no difference.  Note this is stated from a C# perspective - the words are opposite in IL.  In IL, you have four choices in total: no declaration (which actually seals the method), 'virtual' (called 'override' in C#), 'sealed virtual' ('sealed override' in C#) and 'newslot virtual' ('new virtual' or 'virtual' in C#, depending on whether the method already exists in a base class). Methods that implement interface methods.  Methods that implement an interface method must be virtual, so cannot be sealed. Fields.  A field cannot be overridden, only hidden (using the 'new' keyword in C#), so sealing would make no sense.

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• Atheros AR2413 wireless not working after shutdown

  - by Chandrasekhar

  I am using a Ubuntu 11.04 on an Acer aspire 3680 laptop and my wifi is not working. I followed the below commands to install the madwifi driver: sudo su apt-get install subversion cd /usr/src svn checkout http://madwifi-project.org/svn/madwifi/trunk madwifi tar cfvz madwifi.tgz cd madwifi make && make install echo "blacklist ath5k" /etc/modprobe.d/blacklist.conf echo "ath_pci" /etc/modules modprobe ath_pci sudo reboot After installation I am facing the same problem. My wifi wont work after I shutdown. Infact it didn't work after suspend but I rectified that problem by the following commands: Command 1: sudo rmmod -f ath_pci sudo rfkill unblock all sudo modprobe ath_pci along with the command SUSPEND_MODULES=ath_pci added to the /etc/pm/config.d/madwifi directory. So if I suspend and then on my laptop the wifi loads well and doesn't create a problem. But if I shutdown my laptop the wifi never loads again and eachtime I have to run a Ubuntu 9.04 live CD to load it. I did try adding the Command 1 to the /etc/rc.local directory but still it doesn't work. So my question is: What should I do in order to make my wireless work without having to run a live CD of ubuntu 9.04 everytime after shutdown? Thanks. Here are the outputs which one might need: Output 1 chandru@chandru-acer:~$ lspci 00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub (rev 03) 00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03) 00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03) 00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 02) 00:1c.0 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 1 (rev 02) 00:1c.1 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 2 (rev 02) 00:1c.2 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 3 (rev 02) 00:1d.0 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #1 (rev 02) 00:1d.1 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #2 (rev 02) 00:1d.2 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #3 (rev 02) 00:1d.3 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #4 (rev 02) 00:1d.7 USB Controller: Intel Corporation N10/ICH 7 Family USB2 EHCI Controller (rev 02) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2) 00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 02) 00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7 Family) SATA IDE Controller (rev 02) 00:1f.3 SMBus: Intel Corporation N10/ICH 7 Family SMBus Controller (rev 02) 02:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8038 PCI-E Fast Ethernet Controller (rev 14) 0a:03.0 Ethernet controller: Atheros Communications Inc. AR2413 802.11bg NIC (rev 01) 0a:09.0 CardBus bridge: Texas Instruments PCIxx12 Cardbus Controller 0a:09.2 Mass storage controller: Texas Instruments 5-in-1 Multimedia Card Reader (SD/MMC/MS/MS PRO/xD) Output 2: lsmod Module Size Used by wlan_tkip 17074 2 binfmt_misc 13213 1 parport_pc 32111 0 ppdev 12849 0 snd_hda_codec_si3054 12924 1 snd_hda_codec_realtek 255882 1 joydev 17322 0 snd_atiixp_modem 18624 0 snd_via82xx_modem 18305 0 snd_intel8x0m 18493 0 snd_ac97_codec 105614 3 snd_atiixp_modem,snd_via82xx_modem,snd_intel8x0m snd_hda_intel 24113 2 ac97_bus 12642 1 snd_ac97_codec snd_hda_codec 90901 3 snd_hda_codec_si3054,snd_hda_codec_realtek,snd_hda_intel i915 451053 3 snd_hwdep 13274 1 snd_hda_codec snd_pcm 80042 7 snd_hda_codec_si3054,snd_atiixp_modem,snd_via82xx_modem,snd_intel8x0m,snd_ac97_codec,snd_hda_intel,snd_hda_codec snd_seq_midi 13132 0 snd_rawmidi 25269 1 snd_seq_midi drm_kms_helper 40971 1 i915 snd_seq_midi_event 14475 1 snd_seq_midi snd_seq 51291 2 snd_seq_midi,snd_seq_midi_event pcmcia 39671 0 snd_timer 28659 2 snd_pcm,snd_seq snd_seq_device 14110 3 snd_seq_midi,snd_rawmidi,snd_seq drm 184164 4 i915,drm_kms_helper yenta_socket 27230 0 tifm_7xx1 12898 0 wlan_scan_sta 21945 1 ath_rate_sample 17279 1 pcmcia_rsrc 18292 1 yenta_socket psmouse 73312 0 tifm_core 15040 1 tifm_7xx1 snd 55295 18 snd_hda_codec_si3054,snd_hda_codec_realtek,snd_atiixp_modem,snd_via82xx_modem,snd_intel8x0m,snd_ac97_codec,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device serio_raw 12990 0 i2c_algo_bit 13184 1 i915 soundcore 12600 1 snd pcmcia_core 21505 3 pcmcia,yenta_socket,pcmcia_rsrc video 19112 1 i915 ath_pci 183044 0 snd_page_alloc 14073 5 snd_atiixp_modem,snd_via82xx_modem,snd_intel8x0m,snd_hda_intel,snd_pcm wlan 224640 5 wlan_tkip,wlan_scan_sta,ath_rate_sample,ath_pci ath_hal 398701 3 ath_rate_sample,ath_pci lp 13349 0 parport 36746 3 parport_pc,ppdev,lp usbhid 41704 0 hid 77084 1 usbhid sky2 49172 0 Output 3 root@chandru-acer:~# lshw -C network PCI (sysfs) *-network description: Ethernet interface product: 88E8038 PCI-E Fast Ethernet Controller vendor: Marvell Technology Group Ltd. physical id: 0 bus info: pci@0000:02:00.0 logical name: eth0 version: 14 serial: 00:16:36:fb:aa:64 capacity: 100Mbit/s width: 64 bits clock: 33MHz capabilities: pm vpd msi pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=sky2 driverversion=1.28 firmware=N/A latency=0 link=no multicast=yes port=twisted pair resources: irq:43 memory:44000000-44003fff ioport:2000(size=256) *-network description: Wireless interface product: AR2413 802.11bg NIC vendor: Atheros Communications Inc. physical id: 3 bus info: pci@0000:0a:03.0 logical name: wifi0 version: 01 serial: 00:19:7d:d3:0c:fd width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list logical ethernet physical wireless configuration: broadcast=yes driver=ath_pci ip=192.168.1.6 latency=96 maxlatency=28 mingnt=10 multicast=yes wireless=IEEE 802.11g resources: irq:18 memory:d0000000-d000ffff Output 4 root@chandru-acer:~# lsmod | grep ath_pci ath_pci 183044 0 wlan 224640 5 wlan_tkip,wlan_scan_sta,ath_rate_sample,ath_pci ath_hal 398701 3 ath_rate_sample,ath_pci

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• Import problem with PyCrypto in Jython

  - by Arg

  Hello, I am currently trying to get python bittorrent tracker running inside of jython and i encountered this problem: the tracker uses PyCrypto library which i compiled for my platform and added into the python path. When i try to run code, however, i get following error: Exception in thread "MainThread" Traceback (most recent call last): File "./python_dep/BitTorrent-5.2.2/bittorrent-tracker.py", line 21, in <module> from BitTorrent.track import track File "./python_dep/BitTorrent-5.2.2/BitTorrent/track.py", line 50, in <module> from BitTorrent.UI import Size File "./python_dep/BitTorrent-5.2.2/BitTorrent/UI.py", line 37, in <module> from BitTorrent.MultiTorrent import UnknownInfohash, TorrentAlreadyInQueue, TorrentAlreadyRunning, TorrentNotRunning File "./python_dep/BitTorrent-5.2.2/BitTorrent/MultiTorrent.py", line 25, in <module> from BitTorrent.Torrent import Feedback, Torrent File "./python_dep/BitTorrent-5.2.2/BitTorrent/Torrent.py", line 32, in <module> from BitTorrent.ConnectionManager import ConnectionManager File "./python_dep/BitTorrent-5.2.2/BitTorrent/ConnectionManager.py", line 22, in <module> from BitTorrent.Connector import Connector File "./python_dep/BitTorrent-5.2.2/BitTorrent/Connector.py", line 27, in <module> from Crypto.Cipher import ARC4 ImportError: cannot import name ARC4 Java Result: 1 I am pretty sure that the library is in the python path, because command import Crypto.Cipher works, while from Crypto.Cipher import ARC4 does not. The java code i run looks like this: package jythTest; import org.python.util.PythonInterpreter; public class Main { public static void main(String[] args) { PythonInterpreter pythonInterpreter = new PythonInterpreter(); pythonInterpreter.exec("import sys"); pythonInterpreter.exec("sys.path.append(\"./python_dep/BitTorrent-5.2.2/\")"); pythonInterpreter.exec("sys.path.append(\"./python_dep/Twisted-10.0.0/\")"); pythonInterpreter.exec("sys.path.append(\"./python_dep/Zope-3.4.0/build/lib.linux-i686-2.6\")"); pythonInterpreter.exec("sys.path.append(\"./python_dep\")"); pythonInterpreter.exec("sys.path.append(\"./python_dep/pycrypto-2.0.1/build/lib.linux-i686-2.6\")"); pythonInterpreter.exec("sys.path.append(\"import Crypto.Cipher\")"); //pythonInterpreter.exec("print sys.path"); pythonInterpreter.execfile("./python_dep/BitTorrent-5.2.2/bittorrent-tracker.py"); } } Thanks in advance to anyone who could provide any kind of help.

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• Patterns for dynamic CMS components (event driven?)

  - by CitrusTree

  Sorry my title is not great, this is my first real punt at moving 100% to OO as I've been procedural for more years than I can remember. I'm finding it hard to understand if what I'm trying to do is possible. Depending on people's thoughts on the 2 following points, I'll go down that route. The CMS I'm putting together is quote small, however focuses very much on different types of content. I could easily use Drupal which I'm very comfortable with, but I want to give myself a really good reasons to move myself into design patterns / OO-PHP 1) I have created a base 'content' class which I wish to be able to extend to handle different types of content. The base class, for example, handles HTML content, and extensions might handle XML or PDF output instead. On the other hand, at some point I may wish to extend the base class for a given project completely. I.e. if class 'content-v2' extended class 'content' for that site, any calls to that class should actually call 'content-v2' instead. Is that possible? If the code instantiates an object of type 'content' - I actually want it to instantiate one of type 'content-v2'... I can see how to do it using inheritance, but that appears to involve referring to the class explicitly, I can't see how to link the class I want it to use instead dynamically. 2) Secondly, the way I'm building this at the moment is horrible, I'm not happy with it. It feels very linear indeed - i.e. get session details get content build navigation theme page publish. To do this all the objects are called 1-by-1 which is all very static. I'd like it to be more dynamic so that I can add to it at a later date (very closely related to first question). Is there a way that instead of my orchestrator class calling all the other classes 1-by-1, then building the whole thing up at the end, that instead each of the other classes can 'listen' for specific events, then at the applicable point jump in and do their but? That way the orchestrator class would not need to know what other classes were required, and call them 1-by-1. Sorry if I've got this all twisted in my head. I'm trying to build this so it's really flexible.

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• broadcom 5722 NIC not installed on Ubuntu Server, although driver present

  - by Bastien

  Hello, I just installed Ubuntu Server 10.04 LTS, running kernel 2.6.32-24-server, on a brand new Dell T110 server, supposedly fully compatible with Ubuntu Server. I have two NICs: one ONBOARD, the other additional on PCI. both of them are Broadcom netXtreme 5572. on the first boot of the system, I could see both cards as eth0 and eth1 (with ifconfig) I configured eth0 as static IP (as planned), and did not configure eth1. after rebooting, one of the two NICs "disappeared": it does not appear in ifconfig at all. the one that disappeared is the ONBOARD one. I investigated a bit and found the following things: the card is SEEN, but not "installed", it appears as "UNCLAIMED" in lshw: *-network UNCLAIMED description: Ethernet controller product: NetXtreme BCM5722 Gigabit Ethernet PCI Express vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:04:00.0 version: 00 width: 64 bits clock: 33MHz capabilities: pm vpd msi pciexpress cap_list configuration: latency=0 resources: memory:df9f0000-df9fffff *-network description: Ethernet interface product: NetXtreme BCM5722 Gigabit Ethernet PCI Express vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:05:00.0 logical name: eth0 version: 00 serial: 00:10:18:60:23:64 size: 100MB/s capacity: 1GB/s width: 64 bits clock: 33MHz capabilities: pm vpd msi pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.102 duplex=full firmware=5722-v3.09 ip=10.129.167.25 latency=0 link=yes multicast=yes port=twisted pair speed=100MB/s resources: irq:35 memory:dfaf0000-dfafffff so I checked my dmesg and found a few strange lines, showing, there actually is a problem bringing up this card: [ 3.737506] tg3: Could not obtain valid ethernet address, aborting. [ 3.737527] tg3 0000:04:00.0: PCI INT A disabled [ 3.737535] tg3: probe of 0000:04:00.0 failed with error -22 [ 3.737553] alloc irq_desc for 17 on node -1 [ 3.737555] alloc kstat_irqs on node -1 [ 3.737560] tg3 0000:05:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17 [ 3.737566] tg3 0000:05:00.0: setting latency timer to 64 [ 3.793529] eth0: Tigon3 [partno(BCM95722A2202G) rev a200] (PCI Express) MAC address 00:10:18:60:23:64 [ 3.793532] eth0: attached PHY is 5722/5756 (10/100/1000Base-T Ethernet) (WireSpeed[1]) [ 3.793534] eth0: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[0] TSOcap[1] [ 3.793536] eth0: dma_rwctrl[76180000] dma_mask[64-bit] that actually shows that one NIC is recognized, the other is not. I researched a bit more, with lspci -v: 04:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5722 Gigabit Ethernet PCI Express Subsystem: Broadcom Corporation NetXtreme BCM5722 Gigabit Ethernet PCI Express Flags: fast devsel, IRQ 16 Memory at df9f0000 (64-bit, non-prefetchable) [size=64K] Capabilities: [48] Power Management version 3 Capabilities: [50] Vital Product Data <?> Capabilities: [58] Vendor Specific Information <?> Capabilities: [e8] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable- Capabilities: [d0] Express Endpoint, MSI 00 Capabilities: [100] Advanced Error Reporting <?> Capabilities: [13c] Virtual Channel <?> Capabilities: [160] Device Serial Number 00-00-00-fe-ff-00-00-00 Kernel modules: tg3 05:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5722 Gigabit Ethernet PCI Express Subsystem: Broadcom Corporation NetXtreme BCM5722 Gigabit Ethernet PCI Express Flags: bus master, fast devsel, latency 0, IRQ 35 Memory at dfaf0000 (64-bit, non-prefetchable) [size=64K] Expansion ROM at <ignored> [disabled] Capabilities: [48] Power Management version 3 Capabilities: [50] Vital Product Data <?> Capabilities: [58] Vendor Specific Information <?> Capabilities: [e8] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable+ Capabilities: [d0] Express Endpoint, MSI 00 Capabilities: [100] Advanced Error Reporting <?> Capabilities: [13c] Virtual Channel <?> Capabilities: [160] Device Serial Number 64-23-60-fe-ff-18-10-00 Capabilities: [16c] Power Budgeting <?> Kernel driver in use: tg3 Kernel modules: tg3 here I could see that the MAC address is 00-00-00-FE-FF-00-00-00, which, according to some forum posts on several websites, could be an issue. I've researched everything I could on the net, and found out several people having slightly comparable issues, but they usually involve different HW, and do not provide a proper explanation / solution... I would appreciate if anyone around here has some info to share ! thanks

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• ovs-vsctl: "eth0" is not a valid UUID

  - by Przemek Lach

  I'm trying to setup an open v-switch inside my Ubuntu 12.04 Server VM. I have created three interfaces for this VM and I want to create a port mirror inside of the VM using these there interfaces and open v-switch. There are three Host-Only Adapters: eth0, eth1, eth2. The idea is that three other VM's will be connected to these adapters. One of these VM's will stream UDP video to eth0 and I want the vswitch'd VM to mirror those packets from eth0 onto eth1 and eth2. Each of the VM's connected to eth1 and eth2 will get the same video stream. I performed the following steps to install open v-switch: $ apt-get install python-simplejson python-qt4 python-twisted-conch automake autoconf gcc uml-utilities libtool build-essential $ apt-get install build-essential autoconf automake pkg-config $ wget http://openvswitch.org/releases/openvswitch-1.7.1.tar.gz $ tar xf http://openvswitch.org/releases/openvswitch-1.7.1.tar.gz $ cd http://openvswitch.org/releases/openvswitch-1.7.1.tar.gz $ apt-get install libssl-dev iproute tcpdump linux-headers-`uname -r` $ ./boot.sh $ ./configure - -with-linux=/lib/modules/`uname -r`/build $ make $ sudo make install After installation I configured as follows: $ insmod datapath/linux/openvswitch.ko $ sudo touch /usr/local/etc/ovs-vswitchd.conf $ mkdir -p /usr/local/etc/openvswitch $ ovsdb-tool create /usr/local/etc/openvswitch/conf.db Then I started the server: $ ovsdb-server /usr/local/etc/openvswitch/conf.db \ --remote=punix:/usr/local/var/run/openvswitch/db.sock \ --remote=db:Open_vSwitch,manager_options \ --private-key=db:SSL,private_key \ --certificate=db:SSL,certificate \ --bootstrap-ca-cert=db:SSL,ca_cert --pidfile --detach --log-file $ ovs-vsctl –no-wait init (run only once) $ ovs-vswitchd --pidfile --detach The above steps I got from this tutorial and it all worked fine. I then proceeded to add a port mirror based on the open v-switch documentation under Port Mirroring. I successfully completed the following commands: $ ovs-vsctl add-br br0 $ ovs-vsctl add-port br0 eth0 $ ovs-vsctl add-port br0 eth1 $ ovs-vsctl add-port br0 eth2 $ ifconfig eth0 promisc up $ ifconfig eth1 promisc up $ ifconfig eth2 promisc up At this point when I run ovs-vsctl show I get the following: 75bda8c2-b870-438b-9115-e36288ea1cd8 Bridge "br0" Port "br0" Interface "br0" type: internal Port "eth0" Interface "eth0" Port "eth2" Interface "eth2" Port "eth1" Interface "eth1" And when I run ifconfig I get the following: eth0 Link encap:Ethernet HWaddr 08:00:27:9f:51:ca inet6 addr: fe80::a00:27ff:fe9f:51ca/64 Scope:Link UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1 RX packets:17 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1494 (1.4 KB) TX bytes:468 (468.0 B) eth1 Link encap:Ethernet HWaddr 08:00:27:53:02:d4 inet6 addr: fe80::a00:27ff:fe53:2d4/64 Scope:Link UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1 RX packets:17 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1494 (1.4 KB) TX bytes:468 (468.0 B) eth2 Link encap:Ethernet HWaddr 08:00:27:cb:a5:93 inet6 addr: fe80::a00:27ff:fecb:a593/64 Scope:Link UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1 RX packets:17 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1494 (1.4 KB) TX bytes:468 (468.0 B) eth3 Link encap:Ethernet HWaddr 08:00:27:df:bb:d8 inet addr:192.168.1.139 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::a00:27ff:fedf:bbd8/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:2211 errors:0 dropped:0 overruns:0 frame:0 TX packets:1196 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:182987 (182.9 KB) TX bytes:125441 (125.4 KB) NOTE: I use eth3 as a bridge adapter for SSH'ing into the VM. So now, I think I've done everything correctly but when I try to create the bridge using the following command: $ ovs-vsctl -- set Bridge br0 mirrors=@m -- --id=@eth0 get Port eth0 -- --id=@eth1 get Port eth1 -- --id=@m create Mirror name=app1Mirror select-dst-port=eth0 select-src-port=@eth0 output-port=@eth1,eth2 I get the following error: ovs-vsctl: "eth0" is not a valid UUID I don't understand why it's not able to find the interfaces?

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• Thread placement policies on NUMA systems - update

  - by Dave

  In a prior blog entry I noted that Solaris used a "maximum dispersal" placement policy to assign nascent threads to their initial processors. The general idea is that threads should be placed as far away from each other as possible in the resource topology in order to reduce resource contention between concurrently running threads. This policy assumes that resource contention -- pipelines, memory channel contention, destructive interference in the shared caches, etc -- will likely outweigh (a) any potential communication benefits we might achieve by packing our threads more densely onto a subset of the NUMA nodes, and (b) benefits of NUMA affinity between memory allocated by one thread and accessed by other threads. We want our threads spread widely over the system and not packed together. Conceptually, when placing a new thread, the kernel picks the least loaded node NUMA node (the node with lowest aggregate load average), and then the least loaded core on that node, etc. Furthermore, the kernel places threads onto resources -- sockets, cores, pipelines, etc -- without regard to the thread's process membership. That is, initial placement is process-agnostic. Keep reading, though. This description is incorrect. On Solaris 10 on a SPARC T5440 with 4 x T2+ NUMA nodes, if the system is otherwise unloaded and we launch a process that creates 20 compute-bound concurrent threads, then typically we'll see a perfect balance with 5 threads on each node. We see similar behavior on an 8-node x86 x4800 system, where each node has 8 cores and each core is 2-way hyperthreaded. So far so good; this behavior seems in agreement with the policy I described in the 1st paragraph. I recently tried the same experiment on a 4-node T4-4 running Solaris 11. Both the T5440 and T4-4 are 4-node systems that expose 256 logical thread contexts. To my surprise, all 20 threads were placed onto just one NUMA node while the other 3 nodes remained completely idle. I checked the usual suspects such as processor sets inadvertently left around by colleagues, processors left offline, and power management policies, but the system was configured normally. I then launched multiple concurrent instances of the process, and, interestingly, all the threads from the 1st process landed on one node, all the threads from the 2nd process landed on another node, and so on. This happened even if I interleaved thread creating between the processes, so I was relatively sure the effect didn't related to thread creation time, but rather that placement was a function of process membership. I this point I consulted the Solaris sources and talked with folks in the Solaris group. The new Solaris 11 behavior is intentional. The kernel is no longer using a simple maximum dispersal policy, and thread placement is process membership-aware. Now, even if other nodes are completely unloaded, the kernel will still try to pack new threads onto the home lgroup (socket) of the primordial thread until the load average of that node reaches 50%, after which it will pick the next least loaded node as the process's new favorite node for placement. On the T4-4 we have 64 logical thread contexts (strands) per socket (lgroup), so if we launch 48 concurrent threads we will find 32 placed on one node and 16 on some other node. If we launch 64 threads we'll find 32 and 32. That means we can end up with our threads clustered on a small subset of the nodes in a way that's quite different that what we've seen on Solaris 10. So we have a policy that allows process-aware packing but reverts to spreading threads onto other nodes if a node becomes too saturated. It turns out this policy was enabled in Solaris 10, but certain bugs suppressed the mixed packing/spreading behavior. There are configuration variables in /etc/system that allow us to dial the affinity between nascent threads and their primordial thread up and down: see lgrp_expand_proc_thresh, specifically. In the OpenSolaris source code the key routine is mpo_update_tunables(). This method reads the /etc/system variables and sets up some global variables that will subsequently be used by the dispatcher, which calls lgrp_choose() in lgrp.c to place nascent threads. Lgrp_expand_proc_thresh controls how loaded an lgroup must be before we'll consider homing a process's threads to another lgroup. Tune this value lower to have it spread your process's threads out more. To recap, the 'new' policy is as follows. Threads from the same process are packed onto a subset of the strands of a socket (50% for T-series). Once that socket reaches the 50% threshold the kernel then picks another preferred socket for that process. Threads from unrelated processes are spread across sockets. More precisely, different processes may have different preferred sockets (lgroups). Beware that I've simplified and elided details for the purposes of explication. The truth is in the code. Remarks: It's worth noting that initial thread placement is just that. If there's a gross imbalance between the load on different nodes then the kernel will migrate threads to achieve a better and more even distribution over the set of available nodes. Once a thread runs and gains some affinity for a node, however, it becomes "stickier" under the assumption that the thread has residual cache residency on that node, and that memory allocated by that thread resides on that node given the default "first-touch" page-level NUMA allocation policy. Exactly how the various policies interact and which have precedence under what circumstances could the topic of a future blog entry. The scheduler is work-conserving. The x4800 mentioned above is an interesting system. Each of the 8 sockets houses an Intel 7500-series processor. Each processor has 3 coherent QPI links and the system is arranged as a glueless 8-socket twisted ladder "mobius" topology. Nodes are either 1 or 2 hops distant over the QPI links. As an aside the mapping of logical CPUIDs to physical resources is rather interesting on Solaris/x4800. On SPARC/Solaris the CPUID layout is strictly geographic, with the highest order bits identifying the socket, the next lower bits identifying the core within that socket, following by the pipeline (if present) and finally the logical thread context ("strand") on the core. But on Solaris on the x4800 the CPUID layout is as follows. [6:6] identifies the hyperthread on a core; bits [5:3] identify the socket, or package in Intel terminology; bits [2:0] identify the core within a socket. Such low-level details should be of interest only if you're binding threads -- a bad idea, the kernel typically handles placement best -- or if you're writing NUMA-aware code that's aware of the ambient placement and makes decisions accordingly. Solaris introduced the so-called critical-threads mechanism, which is expressed by putting a thread into the FX scheduling class at priority 60. The critical-threads mechanism applies to placement on cores, not on sockets, however. That is, it's an intra-socket policy, not an inter-socket policy. Solaris 11 introduces the Power Aware Dispatcher (PAD) which packs threads instead of spreading them out in an attempt to be able to keep sockets or cores at lower power levels. Maximum dispersal may be good for performance but is anathema to power management. PAD is off by default, but power management polices constitute yet another confounding factor with respect to scheduling and dispatching. If your threads communicate heavily -- one thread reads cache lines last written by some other thread -- then the new dense packing policy may improve performance by reducing traffic on the coherent interconnect. On the other hand if your threads in your process communicate rarely, then it's possible the new packing policy might result on contention on shared computing resources. Unfortunately there's no simple litmus test that says whether packing or spreading is optimal in a given situation. The answer varies by system load, application, number of threads, and platform hardware characteristics. Currently we don't have the necessary tools and sensoria to decide at runtime, so we're reduced to an empirical approach where we run trials and try to decide on a placement policy. The situation is quite frustrating. Relatedly, it's often hard to determine just the right level of concurrency to optimize throughput. (Understanding constructive vs destructive interference in the shared caches would be a good start. We could augment the lines with a small tag field indicating which strand last installed or accessed a line. Given that, we could augment the CPU with performance counters for misses where a thread evicts a line it installed vs misses where a thread displaces a line installed by some other thread.)

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• Refactoring a Single Rails Model with large methods & long join queries trying to do everything

  - by Kelseydh

  I have a working Ruby on Rails Model that I suspect is inefficient, hard to maintain, and full of unnecessary SQL join queries. I want to optimize and refactor this Model (Quiz.rb) to comply with Rails best practices, but I'm not sure how I should do it. The Rails app is a game that has Missions with many Stages. Users complete Stages by answering Questions that have correct or incorrect Answers. When a User tries to complete a stage by answering questions, the User gets a Quiz entry with many Attempts. Each Attempt records an Answer submitted for that Question within the Stage. A user completes a stage or mission by getting every Attempt correct, and their progress is tracked by adding a new entry to the UserMission & UserStage join tables. All of these features work, but unfortunately the Quiz.rb Model has been twisted to handle almost all of it exclusively. The callbacks began at 'Quiz.rb', and because I wasn't sure how to leave the Quiz Model during a multi-model update, I resorted to using Rails Console to have the @quiz instance variable via self.some_method do all the heavy lifting to retrieve every data value for the game's business logic; resulting in large extended join queries that "dance" all around the Database schema. The Quiz.rb Model that Smells: class Quiz < ActiveRecord::Base belongs_to :user has_many :attempts, dependent: :destroy before_save :check_answer before_save :update_user_mission_and_stage accepts_nested_attributes_for :attempts, :reject_if => lambda { |a| a[:answer_id].blank? }, :allow_destroy => true #Checks every answer within each quiz, adding +1 for each correct answer #within a stage quiz, and -1 for each incorrect answer def check_answer stage_score = 0 self.attempts.each do |attempt| if attempt.answer.correct? == true stage_score += 1 elsif attempt.answer.correct == false stage_score - 1 end end stage_score end def winner return true end def update_user_mission_and_stage ####### #Step 1: Checks if UserMission exists, finds or creates one. #if no UserMission for the current mission exists, creates a new UserMission if self.user_has_mission? == false @user_mission = UserMission.new(user_id: self.user.id, mission_id: self.current_stage.mission_id, available: true) @user_mission.save else @user_mission = self.find_user_mission end ####### #Step 2: Checks if current UserStage exists, stops if true to prevent duplicate entry if self.user_has_stage? @user_mission.save return true else ####### ##Step 3: if step 2 returns false: ##Initiates UserStage creation instructions #checks for winner (winner actions need to be defined) if they complete last stage of last mission for a given orientation if self.passed? && self.is_last_stage? && self.is_last_mission? create_user_stage_and_update_user_mission self.winner #NOTE: The rest are the same, but specify conditions that are available to add badges or other actions upon those conditions occurring: ##if user completes first stage of a mission elsif self.passed? && self.is_first_stage? && self.is_first_mission? create_user_stage_and_update_user_mission #creates user badge for finishing first stage of first mission self.user.add_badge(5) self.user.activity_logs.create(description: "granted first-stage badge", type_event: "badge", value: "first-stage") #If user completes last stage of a given mission, creates a new UserMission elsif self.passed? && self.is_last_stage? && self.is_first_mission? create_user_stage_and_update_user_mission #creates user badge for finishing first mission self.user.add_badge(6) self.user.activity_logs.create(description: "granted first-mission badge", type_event: "badge", value: "first-mission") elsif self.passed? create_user_stage_and_update_user_mission else self.passed? == false return true end end end #Creates a new UserStage record in the database for a successful Quiz question passing def create_user_stage_and_update_user_mission @nu_stage = @user_mission.user_stages.new(user_id: self.user.id, stage_id: self.current_stage.id) @nu_stage.save @user_mission.save self.user.add_points(50) end #Boolean that defines passing a stage as answering every question in that stage correct def passed? self.check_answer >= self.number_of_questions end #Returns the number of questions asked for that stage's quiz def number_of_questions self.attempts.first.answer.question.stage.questions.count end #Returns the current_stage for the Quiz, routing through 1st attempt in that Quiz def current_stage self.attempts.first.answer.question.stage end #Gives back the position of the stage relative to its mission. def stage_position self.attempts.first.answer.question.stage.position end #will find the user_mission for the current user and stage if it exists def find_user_mission self.user.user_missions.find_by_mission_id(self.current_stage.mission_id) end #Returns true if quiz was for the last stage within that mission #helpful for triggering actions related to a user completing a mission def is_last_stage? self.stage_position == self.current_stage.mission.stages.last.position end #Returns true if quiz was for the first stage within that mission #helpful for triggering actions related to a user completing a mission def is_first_stage? self.stage_position == self.current_stage.mission.stages_ordered.first.position end #Returns true if current user has a UserMission for the current stage def user_has_mission? self.user.missions.ids.include?(self.current_stage.mission.id) end #Returns true if current user has a UserStage for the current stage def user_has_stage? self.user.stages.include?(self.current_stage) end #Returns true if current user is on the last mission based on position within a given orientation def is_first_mission? self.user.missions.first.orientation.missions.by_position.first.position == self.current_stage.mission.position end #Returns true if current user is on the first stage & mission of a given orientation def is_last_mission? self.user.missions.first.orientation.missions.by_position.last.position == self.current_stage.mission.position end end My Question Currently my Rails server takes roughly 500ms to 1 sec to process single @quiz.save action. I am confident that the slowness here is due to sloppy code, not bad Database ERD design. What does a better solution look like? And specifically: Should I use join queries to retrieve values like I did here, or is it better to instantiate new objects within the model instead? Or am I missing a better solution? How should update_user_mission_and_stage be refactored to follow best practices? Relevant Code for Reference: quizzes_controller.rb w/ Controller Route Initiating Callback: class QuizzesController < ApplicationController before_action :find_stage_and_mission before_action :find_orientation before_action :find_question def show end def create @user = current_user @quiz = current_user.quizzes.new(quiz_params) if @quiz.save if @quiz.passed? if @mission.next_mission.nil? && @stage.next_stage.nil? redirect_to root_path, notice: "Congratulations, you have finished the last mission!" elsif @stage.next_stage.nil? redirect_to [@mission.next_mission, @mission.first_stage], notice: "Correct! Time for Mission #{@mission.next_mission.position}", info: "Starting next mission" else redirect_to [@mission, @stage.next_stage], notice: "Answer Correct! You passed the stage!" end else redirect_to [@mission, @stage], alert: "You didn't get every question right, please try again." end else redirect_to [@mission, @stage], alert: "Sorry. We were unable to save your answer. Please contact the admministrator." end @questions = @stage.questions.all end private def find_stage_and_mission @stage = Stage.find(params[:stage_id]) @mission = @stage.mission end def find_question @question = @stage.questions.find_by_id params[:id] end def quiz_params params.require(:quiz).permit(:user_id, :attempt_id, {attempts_attributes: [:id, :quiz_id, :answer_id]}) end def find_orientation @orientation = @mission.orientation @missions = @orientation.missions.by_position end end Overview of Relevant ERD Database Relationships: Mission - Stage - Question - Answer - Attempt <- Quiz <- User Mission - UserMission <- User Stage - UserStage <- User Other Models: Mission.rb class Mission < ActiveRecord::Base belongs_to :orientation has_many :stages has_many :user_missions, dependent: :destroy has_many :users, through: :user_missions #SCOPES scope :by_position, -> {order(position: :asc)} def stages_ordered stages.order(:position) end def next_mission self.orientation.missions.find_by_position(self.position.next) end def first_stage next_mission.stages_ordered.first end end Stage.rb: class Stage < ActiveRecord::Base belongs_to :mission has_many :questions, dependent: :destroy has_many :user_stages, dependent: :destroy has_many :users, through: :user_stages accepts_nested_attributes_for :questions, reject_if: :all_blank, allow_destroy: true def next_stage self.mission.stages.find_by_position(self.position.next) end end Question.rb class Question < ActiveRecord::Base belongs_to :stage has_many :answers, dependent: :destroy accepts_nested_attributes_for :answers, :reject_if => lambda { |a| a[:body].blank? }, :allow_destroy => true end Answer.rb: class Answer < ActiveRecord::Base belongs_to :question has_many :attempts, dependent: :destroy end Attempt.rb: class Attempt < ActiveRecord::Base belongs_to :answer belongs_to :quiz end User.rb: class User < ActiveRecord::Base belongs_to :school has_many :activity_logs has_many :user_missions, dependent: :destroy has_many :missions, through: :user_missions has_many :user_stages, dependent: :destroy has_many :stages, through: :user_stages has_many :orientations, through: :school has_many :quizzes, dependent: :destroy has_many :attempts, through: :quizzes def latest_stage_position self.user_missions.last.user_stages.last.stage.position end end UserMission.rb class UserMission < ActiveRecord::Base belongs_to :user belongs_to :mission has_many :user_stages, dependent: :destroy end UserStage.rb class UserStage < ActiveRecord::Base belongs_to :user belongs_to :stage belongs_to :user_mission end

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• NUMA-aware placement of communication variables

  - by Dave

  For classic NUMA-aware programming I'm typically most concerned about simple cold, capacity and compulsory misses and whether we can satisfy the miss by locally connected memory or whether we have to pull the line from its home node over the coherent interconnect -- we'd like to minimize channel contention and conserve interconnect bandwidth. That is, for this style of programming we're quite aware of where memory is homed relative to the threads that will be accessing it. Ideally, a page is collocated on the node with the thread that's expected to most frequently access the page, as simple misses on the page can be satisfied without resorting to transferring the line over the interconnect. The default "first touch" NUMA page placement policy tends to work reasonable well in this regard. When a virtual page is first accessed, the operating system will attempt to provision and map that virtual page to a physical page allocated from the node where the accessing thread is running. It's worth noting that the node-level memory interleaving granularity is usually a multiple of the page size, so we can say that a given page P resides on some node N. That is, the memory underlying a page resides on just one node. But when thinking about accesses to heavily-written communication variables we normally consider what caches the lines underlying such variables might be resident in, and in what states. We want to minimize coherence misses and cache probe activity and interconnect traffic in general. I don't usually give much thought to the location of the home NUMA node underlying such highly shared variables. On a SPARC T5440, for instance, which consists of 4 T2+ processors connected by a central coherence hub, the home node and placement of heavily accessed communication variables has very little impact on performance. The variables are frequently accessed so likely in M-state in some cache, and the location of the home node is of little consequence because a requester can use cache-to-cache transfers to get the line. Or at least that's what I thought. Recently, though, I was exploring a simple shared memory point-to-point communication model where a client writes a request into a request mailbox and then busy-waits on a response variable. It's a simple example of delegation based on message passing. The server polls the request mailbox, and having fetched a new request value, performs some operation and then writes a reply value into the response variable. As noted above, on a T5440 performance is insensitive to the placement of the communication variables -- the request and response mailbox words. But on a Sun/Oracle X4800 I noticed that was not the case and that NUMA placement of the communication variables was actually quite important. For background an X4800 system consists of 8 Intel X7560 Xeons . Each package (socket) has 8 cores with 2 contexts per core, so the system is 8x8x2. Each package is also a NUMA node and has locally attached memory. Every package has 3 point-to-point QPI links for cache coherence, and the system is configured with a twisted ladder "mobius" topology. The cache coherence fabric is glueless -- there's not central arbiter or coherence hub. The maximum distance between any two nodes is just 2 hops over the QPI links. For any given node, 3 other nodes are 1 hop distant and the remaining 4 nodes are 2 hops distant. Using a single request (client) thread and a single response (server) thread, a benchmark harness explored all permutations of NUMA placement for the two threads and the two communication variables, measuring the average round-trip-time and throughput rate between the client and server. In this benchmark the server simply acts as a simple transponder, writing the request value plus 1 back into the reply field, so there's no particular computation phase and we're only measuring communication overheads. In addition to varying the placement of communication variables over pairs of nodes, we also explored variations where both variables were placed on one page (and thus on one node) -- either on the same cache line or different cache lines -- while varying the node where the variables reside along with the placement of the threads. The key observation was that if the client and server threads were on different nodes, then the best placement of variables was to have the request variable (written by the client and read by the server) reside on the same node as the client thread, and to place the response variable (written by the server and read by the client) on the same node as the server. That is, if you have a variable that's to be written by one thread and read by another, it should be homed with the writer thread. For our simple client-server model that means using split request and response communication variables with unidirectional message flow on a given page. This can yield up to twice the throughput of less favorable placement strategies. Our X4800 uses the QPI 1.0 protocol with source-based snooping. Briefly, when node A needs to probe a cache line it fires off snoop requests to all the nodes in the system. Those recipients then forward their response not to the original requester, but to the home node H of the cache line. H waits for and collects the responses, adjudicates and resolves conflicts and ensures memory-model ordering, and then sends a definitive reply back to the original requester A. If some node B needed to transfer the line to A, it will do so by cache-to-cache transfer and let H know about the disposition of the cache line. A needs to wait for the authoritative response from H. So if a thread on node A wants to write a value to be read by a thread on node B, the latency is dependent on the distances between A, B, and H. We observe the best performance when the written-to variable is co-homed with the writer A. That is, we want H and A to be the same node, as the writer doesn't need the home to respond over the QPI link, as the writer and the home reside on the very same node. With architecturally informed placement of communication variables we eliminate at least one QPI hop from the critical path. Newer Intel processors use the QPI 1.1 coherence protocol with home-based snooping. As noted above, under source-snooping a requester broadcasts snoop requests to all nodes. Those nodes send their response to the home node of the location, which provides memory ordering, reconciles conflicts, etc., and then posts a definitive reply to the requester. In home-based snooping the snoop probe goes directly to the home node and are not broadcast. The home node can consult snoop filters -- if present -- and send out requests to retrieve the line if necessary. The 3rd party owner of the line, if any, can respond either to the home or the original requester (or even to both) according to the protocol policies. There are myriad variations that have been implemented, and unfortunately vendor terminology doesn't always agree between vendors or with the academic taxonomy papers. The key is that home-snooping enables the use of a snoop filter to reduce interconnect traffic. And while home-snooping might have a longer critical path (latency) than source-based snooping, it also may require fewer messages and less overall bandwidth. It'll be interesting to reprise these experiments on a platform with home-based snooping. While collecting data I also noticed that there are placement concerns even in the seemingly trivial case when both threads and both variables reside on a single node. Internally, the cores on each X7560 package are connected by an internal ring. (Actually there are multiple contra-rotating rings). And the last-level on-chip cache (LLC) is partitioned in banks or slices, which with each slice being associated with a core on the ring topology. A hardware hash function associates each physical address with a specific home bank. Thus we face distance and topology concerns even for intra-package communications, although the latencies are not nearly the magnitude we see inter-package. I've not seen such communication distance artifacts on the T2+, where the cache banks are connected to the cores via a high-speed crossbar instead of a ring -- communication latencies seem more regular.

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• Ubuntu 12.04 + Wifi not working

  - by user171154

  i'm having problems connecting over wireless. At the moment, I'm using wicd. It seems to get stuck on "Verifying AP association...". Without wicd I can get the connection up and ping the Net - but if I take eth0 down (ifconfig eth0 down), my wireless goes away too (same result if I unplug the wire instead). wicd is the only way I can bring eth0 back (which is the main reason I'm using it) - ifconfig eth0 and/or ifup eth0 do not re-enable the connection (I just discovered it leaves out the gateway. Adding the gateway back in re-enables the connection including wifi; I didn't want to delete the info about wicd above in case it gives someone an idea.) Doing it manually, despite the errors (which it would be nice to also resolve) - allows me to ping the outside world: ifup wlan0 ioctl[SIOCSIWENCODEEXT]: Invalid argument ioctl[SIOCSIWENCODEEXT]: Invalid argument ssh stop/waiting ssh start/running, process 17336 ping -I wlan0 -c 4 8.8.8.8 PING 8.8.8.8 (8.8.8.8) from 192.168.0.12 wlan0: 56(84) bytes of data. 64 bytes from 8.8.8.8: icmp_req=1 ttl=43 time=48.8 ms 64 bytes from 8.8.8.8: icmp_req=2 ttl=43 time=47.9 ms 64 bytes from 8.8.8.8: icmp_req=3 ttl=43 time=48.7 ms 64 bytes from 8.8.8.8: icmp_req=4 ttl=43 time=53.2 ms --- 8.8.8.8 ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 3003ms rtt min/avg/max/mdev = 47.975/49.711/53.235/2.063 ms # iwconfig lo no wireless extensions. wlan0 IEEE 802.11bgn ESSID:"TPLINK" Mode:Managed Frequency:2.427 GHz Access Point: 64:66:xx:xx:xx:22 Bit Rate=108 Mb/s Tx-Power=27 dBm Retry long limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Management:off Link Quality=70/70 Signal level=-39 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:3 Missed beacon:0 bus info: pci@0000:03:00.0 logical name: wlan0 version: 01 serial: f0:7d:68:c1:b4:13 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=ath9k driverversion=3.2.0-67-generic-pae firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:17 memory:dfbf0000-dfbfffff ip route default via 192.168.0.1 dev eth0 default via 192.168.0.1 dev wlan0 metric 100 169.254.0.0/16 dev wlan0 scope link metric 1000 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.102 192.168.0.0/24 dev wlan0 proto kernel scope link src 192.168.0.12 (For the record, I have no idea what the 169.254.0.0 address is doing there.) uname -a 3.2.0-67-generic-pae #101-Ubuntu SMP Tue Jul 15 18:04:54 UTC 2014 i686 i686 i386 GNU/Linux lshw -C network *-network description: Ethernet interface product: NetXtreme BCM5751 Gigabit Ethernet PCI Express vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: eth0 version: 01 serial: 00:11:11:59:fc:09 size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm vpd msi pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.121 duplex=full firmware=5751-v3.23a ip=192.168.0.102 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s resources: irq:16 memory:dfcf0000-dfcfffff *-network description: Wireless interface product: AR5418 Wireless Network Adapter [AR5008E 802.11(a)bgn] (PCI-Express) vendor: Qualcomm Atheros physical id: 0 /etc/network/interfaces # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback source /etc/network/interfaces.eth0 source /etc/network/interfaces.wlan0 /etc/network/interfaces.eth0 #Main Interface auto eth0 iface eth0 inet static address 192.168.0.102 netmask 255.255.255.0 gateway 192.168.0.1 /etc/network/interfaces.wlan0 auto wlan0 iface wlan0 inet static address 192.168.0.12 gateway 192.168.0.1 dns-nameservers 192.168.0.1 8.8.8.8 netmask 255.255.255.0 wpa-driver wext wpa-ssid TPLINK wpa-ap-scan 1 wpa-proto RSN wpa-pairwise CCMP wpa-group CCMP wpa-key-mgmt WPA-PSK wpa-psk dca1badb5fd4e9axxx4xxdaaxxfa91xx610bxx6a7d57ef67af9809dxx6af42e39 /etc/wpa_supplicant.conf ctrl_interface=/var/run/wpa_supplicant network={ ssid="TPLINK" psk="my password" key_mgmt=WPA-PSK proto=RSN pairwise=CCMP group=CCMP } ifdown eth0 ifdown: interface eth0 not configured ifconfig eth0 Link encap:Ethernet HWaddr 00:11:xx:xx:xx:09 inet addr:192.168.0.102 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::211:11ff:fe59:fc09/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:213690 errors:0 dropped:0 overruns:0 frame:0 TX packets:155266 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:220057808 (220.0 MB) TX bytes:21137696 (21.1 MB) Interrupt:16 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:196412 errors:0 dropped:0 overruns:0 frame:0 TX packets:196412 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:153270697 (153.2 MB) TX bytes:153270697 (153.2 MB) wlan0 Link encap:Ethernet HWaddr f0:7d:xx:xx:xx:13 inet addr:192.168.0.12 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::f27d:68ff:fec1:b413/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:11335 errors:0 dropped:0 overruns:0 frame:0 TX packets:7287 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2563290 (2.5 MB) TX bytes:855746 (855.7 KB) ifconfig eth0 down ifconfig eth0 Link encap:Ethernet HWaddr 00:xx:xx:xx:xx:09 inet addr:192.168.0.102 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::211:11ff:fe59:fc09/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:2 errors:0 dropped:0 overruns:0 frame:0 TX packets:1 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:192 (192.0 B) TX bytes:94 (94.0 B) Interrupt:16 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:196418 errors:0 dropped:0 overruns:0 frame:0 TX packets:196418 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:153270871 (153.2 MB) TX bytes:153270871 (153.2 MB) wlan0 Link encap:Ethernet HWaddr f0:7d:xx:xx:xx:13 inet addr:192.168.0.12 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::f27d:68ff:fec1:b413/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:11359 errors:0 dropped:0 overruns:0 frame:0 TX packets:7293 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2565482 (2.5 MB) TX bytes:856363 (856.3 KB) ip route default via 192.168.0.1 dev wlan0 metric 100 169.254.0.0/16 dev wlan0 scope link metric 1000 192.168.0.0/24 dev wlan0 proto kernel scope link src 192.168.0.12 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.102 ping -I wlan0 -c 4 8.8.8.8 PING 8.8.8.8 (8.8.8.8) from 192.168.0.12 wlan0: 56(84) bytes of data. --- 8.8.8.8 ping statistics --- 4 packets transmitted, 0 received, 100% packet loss, time 3024ms ping -I eth0 -c 3 router PING router (192.168.0.1) from 192.168.0.102 eth0: 56(84) bytes of data. --- router ping statistics --- 3 packets transmitted, 0 received, 100% packet loss, time 2015ms ping -I wlan0 -c 3 router PING router (192.168.0.1) from 192.168.0.12 wlan0: 56(84) bytes of data. --- router ping statistics --- 3 packets transmitted, 0 received, 100% packet loss, time 2014ms Let me know if you need more info. Thank you in advance.

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• Unable to connect to Wireless after installing Ubuntu 12.10

  - by Moulik

  I am using Asus U56E laptop and after installing Ubuntu 12.10 alongside Windows 8, I am unable to connect to the Wireless. I have been trying to solve this problem since two weeks and couldn't solve it. Please help. Any answer would be appreciated. Here are some command-line results. lspci -v | grep -iA 7 network ubuntu@ubuntu:~$ lspci -v | grep -iA 7 network 02:00.0 Network controller: Intel Corporation Centrino Wireless-N + WiMAX 6150 (rev 67) Subsystem: Intel Corporation Centrino Wireless-N + WiMAX 6150 BGN Flags: bus master, fast devsel, latency 0, IRQ 52 Memory at de800000 (64-bit, non-prefetchable) [size=8K] Capabilities: <access denied> Kernel driver in use: iwlwifi Kernel modules: iwlwifi lsmod | grep iwlwifi ubuntu@ubuntu:~$ lsmod | grep iwlwifi iwlwifi 386826 0 mac80211 539908 1 iwlwifi cfg80211 206566 2 iwlwifi,mac80211 ubuntu@ubuntu:~$ dmesg | grep iwlwifi [ 57.846261] iwlwifi: Intel(R) Wireless WiFi Link AGN driver for Linux, in-tree: [ 57.846264] iwlwifi: Copyright(c) 2003-2012 Intel Corporation [ 57.846336] iwlwifi 0000:02:00.0: >pci_resource_len = 0x00002000 [ 57.846338] iwlwifi 0000:02:00.0: >pci_resource_base = ffffc90000c7c000 [ 57.846341] iwlwifi 0000:02:00.0: >HW Revision ID = 0x67 [ 57.846438] iwlwifi 0000:02:00.0: >irq 52 for MSI/MSI-X [ 59.558335] iwlwifi 0000:02:00.0: >loaded firmware version 41.28.5.1 build 33926 [ 59.558514] iwlwifi 0000:02:00.0: >CONFIG_IWLWIFI_DEBUG disabled [ 59.558516] iwlwifi 0000:02:00.0: >CONFIG_IWLWIFI_DEBUGFS enabled [ 59.558517] iwlwifi 0000:02:00.0: >CONFIG_IWLWIFI_DEVICE_TRACING enabled [ 59.558519] iwlwifi 0000:02:00.0: >CONFIG_IWLWIFI_DEVICE_TESTMODE enabled [ 59.558520] iwlwifi 0000:02:00.0: >CONFIG_IWLWIFI_P2P disabled [ 59.558522] iwlwifi 0000:02:00.0: >Detected Intel(R) Centrino(R) Wireless-N + WiMAX 6150 BGN, REV=0x84 [ 59.558583] iwlwifi 0000:02:00.0: >L1 Disabled; Enabling L0S [ 59.569083] iwlwifi 0000:02:00.0: >device EEPROM VER=0x557, CALIB=0x6 [ 59.569085] iwlwifi 0000:02:00.0: >Device SKU: 0x150 [ 59.569087] iwlwifi 0000:02:00.0: >Valid Tx ant: 0x1, Valid Rx ant: 0x3 [ 59.569100] iwlwifi 0000:02:00.0: >Tunable channels: 13 802.11bg, 0 802.11a channels [ 70.208469] iwlwifi 0000:02:00.0: >L1 Disabled; Enabling L0S [ 70.208648] iwlwifi 0000:02:00.0: >Radio type=0x1-0x2-0x0 [ 70.366319] iwlwifi 0000:02:00.0: >L1 Disabled; Enabling L0S [ 70.366470] iwlwifi 0000:02:00.0: >Radio type=0x1-0x2-0x0 sudo lshw -c network ubuntu@ubuntu:~$ sudo lshw -c network *-network description: Wireless interface product: Centrino Wireless-N + WiMAX 6150 vendor: Intel Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: wlan0 version: 67 serial: 40:25:c2:84:99:c4 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=3.5.0-17-generic firmware=41.28.5.1 build 33926 latency=0 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:52 memory:de800000-de801fff *-network description: Ethernet interface product: AR8151 v2.0 Gigabit Ethernet vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:04:00.0 logical name: eth0 version: c0 serial: 54:04:a6:2b:6a:ef capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI latency=0 link=no multicast=yes port=twisted pair resources: irq:54 memory:dd400000-dd43ffff ioport:a000(size=128) ifconfig ubuntu@ubuntu:~$ ifconfig eth0 Link encap:Ethernet HWaddr 54:04:a6:2b:6a:ef UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:176 errors:0 dropped:0 overruns:0 frame:0 TX packets:176 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:14368 (14.3 KB) TX bytes:14368 (14.3 KB) wlan0 Link encap:Ethernet HWaddr 40:25:c2:84:99:c4 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) iwconfig ubuntu@ubuntu:~$ iwconfig eth0 no wireless extensions. lo no wireless extensions. wlan0 IEEE 802.11bgn ESSID:off/any Mode:Managed Access Point: Not-Associated Tx-Power=15 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off iwlist scan ubuntu@ubuntu:~$ iwlist scan eth0 Interface doesn't support scanning. lo Interface doesn't support scanning. wlan0 No scan results nm-tool ubuntu@ubuntu:~$ nm-tool NetworkManager Tool State: disconnected - Device: eth0 ----------------------------------------------------------------- Type: Wired Driver: atl1c State: unavailable Default: no HW Address: 54:04:A6:2B:6A:EF Capabilities: Carrier Detect: yes Wired Properties Carrier: off - Device: wlan0 ---------------------------------------------------------------- Type: 802.11 WiFi Driver: iwlwifi State: disconnected Default: no HW Address: 40:25:C2:84:99:C4 Capabilities: Wireless Properties WEP Encryption: yes WPA Encryption: yes WPA2 Encryption: yes Wireless Access Points hypeness2: Infra, 00:21:29:DA:08:4F, Freq 2462 MHz, Rate 54 Mb/s, Strength 42 WPA love: Infra, 68:7F:74:17:02:66, Freq 2412 MHz, Rate 54 Mb/s, Strength 19 WPA WPA2 DIRECT-MwSCX-3400Pamela: Infra, 02:15:99:A3:3F:AC, Freq 2412 MHz, Rate 54 Mb/s, Strength 22 WPA2 router: Infra, 1C:AF:F7:D6:76:F3, Freq 2417 MHz, Rate 54 Mb/s, Strength 20 WPA2 wing: Infra, E8:40:F2:34:E4:F7, Freq 2437 MHz, Rate 54 Mb/s, Strength 20 WPA WPA2 132LINKSYS: Infra, 00:1A:70:80:1F:E9, Freq 2437 MHz, Rate 54 Mb/s, Strength 57 WEP VMITTAL: Infra, E0:46:9A:3C:F0:C4, Freq 2412 MHz, Rate 54 Mb/s, Strength 27 WEP HP-Print-10-LaserJet 1025: Infra, 7C:E9:D3:7E:F8:10, Freq 2437 MHz, Rate 54 Mb/s, Strength 59 ACNBB: Infra, 00:26:75:22:A6:2F, Freq 2437 MHz, Rate 54 Mb/s, Strength 20 SATKAIVAL: Infra, 00:18:E7:CE:69:A6, Freq 2412 MHz, Rate 54 Mb/s, Strength 69 WPA WPA2 hypeness: Infra, B8:E6:25:24:C3:B1, Freq 2437 MHz, Rate 54 Mb/s, Strength 54 WPA WPA2 CSNetwork: Infra, BC:14:01:58:C5:88, Freq 2437 MHz, Rate 54 Mb/s, Strength 25 WPA WPA2 tharma: Infra, BC:14:01:E2:06:18, Freq 2412 MHz, Rate 54 Mb/s, Strength 15 WPA WPA2 Active2.4: Infra, 10:6F:3F:0E:F3:8E, Freq 2462 MHz, Rate 54 Mb/s, Strength 17 WPA WPA2 ACNBB: Infra, 00:26:75:58:4E:7A, Freq 2437 MHz, Rate 54 Mb/s, Strength 85 KO: Infra, BC:14:01:2E:AF:A8, Freq 2452 MHz, Rate 54 Mb/s, Strength 22 WPA WPA2 FEAR: Infra, 00:18:4D:C0:BC:58, Freq 2462 MHz, Rate 54 Mb/s, Strength 17 WPA Pamela: Infra, BC:14:01:52:F6:F8, Freq 2412 MHz, Rate 54 Mb/s, Strength 24 WPA WPA2 bvrk2: Infra, 78:CD:8E:7B:3C:79, Freq 2457 MHz, Rate 54 Mb/s, Strength 19 WPA WPA2 BELL030: Infra, D8:6C:E9:17:AF:09, Freq 2462 MHz, Rate 54 Mb/s, Strength 22 WPA2 Desai: Infra, 00:1D:7E:52:FB:C5, Freq 2437 MHz, Rate 54 Mb/s, Strength 14 WEP Sritharan: Infra, BC:14:01:E5:59:78, Freq 2462 MHz, Rate 54 Mb/s, Strength 19 WPA WPA2 PFN: Infra, 00:13:10:8B:CF:45, Freq 2437 MHz, Rate 54 Mb/s, Strength 19 WEP rfkill list all ubuntu@ubuntu:~$ rfkill list all 0: asus-wlan: Wireless LAN Soft blocked: no Hard blocked: no 1: asus-wimax: WiMAX Soft blocked: yes Hard blocked: no 2: phy0: Wireless LAN Soft blocked: no Hard blocked: no so these are some more results sudo modprobe -r iwlwifi ubuntu@ubuntu:~$ sudo modprobe -r iwlwifi sudo modprobe iwlwifi 11n_disable=1 ubuntu@ubuntu:~$ sudo modprobe iwlwifi 11n_disable=1 echo "blacklist asus_wmi" | sudo tee -a /etcmodprobe.d/blacklist.conf ubuntu@ubuntu:~$ echo "blacklist asus_wmi" | sudo tee -a /etc/modprobe.d/blacklist.conf blacklist asus_wmi echo "options iwlwifi 11n_disable=1" | sudo tee /etc/modprobe.d/iwlwifi.conf ubuntu@ubuntu:~$ echo "options iwlwifi 11n_disable=1" | sudo tee /etc/modprobe.d/iwlwifi.conf options iwlwifi 11n_disable=1 sudo modprobe -rfv iwlwifi ubuntu@ubuntu:~$ sudo modprobe -rfv iwlwifi rmmod /lib/modules/3.5.0-17-generic/kernel/drivers/net/wireless/iwlwifi/iwlwifi.ko rmmod /lib/modules/3.5.0-17-generic/kernel/net/mac80211/mac80211.ko rmmod /lib/modules/3.5.0-17-generic/kernel/net/wireless/cfg80211.ko sudo modprobe -v iwlwifi ubuntu@ubuntu:~$ sudo modprobe -v iwlwifi insmod /lib/modules/3.5.0-17-generic/kernel/net/wireless/cfg80211.ko insmod /lib/modules/3.5.0-17-generic/kernel/net/mac80211/mac80211.ko insmod /lib/modules/3.5.0-17-generic/kernel/drivers/net/wireless/iwlwifi/iwlwifi.ko 11n_disable=1

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• Wireless networks are not detected at start up in Ubuntu 12.04

  - by Kanhaiya Mishra

  I have recently (three four days ago) installed Ubuntu 12.04 via windows installer i.e. wubi.exe. After the installation completed wireless and Ethernet were both working well. But after restart wireless networks didn't show up while in the network manager both networking and wireless were enabled. Though sometimes after boot it did show the networks available but very rarely. So I went through various posts regarding wireless issues in Ubuntu 12.04 and tried so many things but ended up in nothing satisfactory. I have Broadcom 4313 LAN network controller and brcmsmac driver. Then relying on some suggestions I tried to install bcm-wl driver but couldn't install due to some error in jockeyl.log file. Then i tried fresh installation of the same driver but still could resolve the startup issues with wireless. Then again I reinstalled Ubuntu inside windows using wubi installer. This time again same problem occurred after boot. But this time I successfully installed wl driver before disturbing file-system files of Ubuntu. But again the same issue. This time I noticed some new things: If I inserted Ethernet/LAN cable before startup then wireless networks are available and of course LAN(wired) networks also work. but if i don't plug in cable before startup and then plug it after startup then it didn't detect Ethernet network neither wireless. So I haven't noticed it before that LAN along with wifi also doesn't work after startup. But if i suspend the session and make it sleep and again login then it worked. I tried it every time that WLAN worked perfectly. But still i m unable to resolve that startup problem. Each time i boot first I have to suspend it once then only networks are available. It irritates me each time i reboot/boot my lappy. So please help out of this problem. Any ideas/help regarding this issue would be highly appreciated. Some of the commands that i run gave following results: # lspci 00:00.0 Host bridge: Intel Corporation Core Processor DRAM Controller (rev 12) 00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 12) 00:16.0 Communication controller: Intel Corporation 5 Series/3400 Series Chipset HECI Controller (rev 06) 00:1a.0 USB controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 06) 00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 06) 00:1c.0 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 1 (rev 06) 00:1c.1 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 2 (rev 06) 00:1c.5 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 6 (rev 06) 00:1d.0 USB controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 06) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev a6) 00:1f.0 ISA bridge: Intel Corporation Mobile 5 Series Chipset LPC Interface Controller (rev 06) 00:1f.2 SATA controller: Intel Corporation 5 Series/3400 Series Chipset 6 port SATA AHCI Controller (rev 06) 00:1f.3 SMBus: Intel Corporation 5 Series/3400 Series Chipset SMBus Controller (rev 06) 00:1f.6 Signal processing controller: Intel Corporation 5 Series/3400 Series Chipset Thermal Subsystem (rev 06) 03:00.0 Network controller: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller (rev 01) 04:00.0 Ethernet controller: Atheros Communications Inc. AR8152 v1.1 Fast Ethernet (rev c1) ff:00.0 Host bridge: Intel Corporation Core Processor QuickPath Architecture Generic Non-core Registers (rev 02) ff:00.1 Host bridge: Intel Corporation Core Processor QuickPath Architecture System Address Decoder (rev 02) ff:02.0 Host bridge: Intel Corporation Core Processor QPI Link 0 (rev 02) ff:02.1 Host bridge: Intel Corporation Core Processor QPI Physical 0 (rev 02) ff:02.2 Host bridge: Intel Corporation Core Processor Reserved (rev 02) ff:02.3 Host bridge: Intel Corporation Core Processor Reserved (rev 02) # sudo lshw -C network *-network description: Wireless interface product: BCM4313 802.11b/g/n Wireless LAN Controller vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: eth1 version: 01 serial: 70:f1:a1:49:b6:ab width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=wl0 driverversion=5.100.82.38 ip=192.168.1.7 latency=0 multicast=yes wireless=IEEE 802.11 resources: irq:17 memory:f0500000-f0503fff *-network description: Ethernet interface product: AR8152 v1.1 Fast Ethernet vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:04:00.0 logical name: eth0 version: c1 serial: b8:ac:6f:6b:f7:4a capacity: 100Mbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI firmware=N/A latency=0 link=no multicast=yes port=twisted pair resources: irq:44 memory:f0400000-f043ffff ioport:2000(size=128) # lsmod | grep wl wl 2568210 0 lib80211 14381 2 lib80211_crypt_tkip,wl # sudo iwlist eth1 scanning eth1 Scan completed : Cell 01 - Address: 30:46:9A:85:DA:9A ESSID:"BH DASHIR 2" Mode:Managed Frequency:2.462 GHz (Channel 11) Quality:4/5 Signal level:-60 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK IE: Unknown: DD7F0050F204104A00011010440001021041000100103B000103104700109AFE7D908F8E2D381860668BA2E8D8771021000D4E4554474541522C20496E632E10230009574752363134763130102400095747523631347631301042000538333235381054000800060050F204000110110009574752363134763130100800020084 Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s 12 Mb/s; 48 Mb/s Cell 02 - Address: C0:3F:0E:EB:45:14 ESSID:"BH DASHIR 3" Mode:Managed Frequency:2.462 GHz (Channel 11) Quality:2/5 Signal level:-71 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK IE: Unknown: DD7F0050F204104A00011010440001021041000100103B00010310470010F3C9BBE499D140540F530E7EBEDE2F671021000D4E4554474541522C20496E632E10230009574752363134763130102400095747523631347631301042000538333235381054000800060050F204000110110009574752363134763130100800020084 Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s 12 Mb/s; 48 Mb/s Cell 03 - Address: A0:21:B7:A8:2F:C0 ESSID:"BH DASHIR 4" Mode:Managed Frequency:2.422 GHz (Channel 3) Quality:1/5 Signal level:-86 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK IE: Unknown: DD8B0050F204104A0001101044000102103B0001031047001000000000000010000000A021B7A82FC01021000D4E6574676561722C20496E632E10230009574E523130303076321024000456324831104200046E6F6E651054000800060050F20400011011001B574E5231303030763228576972656C6573732041502D322E344729100800020086103C000103 Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s

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• Linux networking crash: best steps to find out the cause?

  - by Aron Rotteveel

  One of our Linux (CentOS) servers was unreachable last night. The server was not reachable in any way except for the remote console. After logging in with the remote console, it turned out I could not ping any outside hosts either. A simple service network restart solved the issue, but I am still wondering what could have caused this. My log files seem to indicate no error at all (except for the various daemons that need a network connection and failed after the network failure). Are there any additional steps I can take to find out the cause of this problem? EDIT: this just happened again. The server was completely unresponsive until I issued a networking service restart. Any advise is welcome. Could this be caused by a faulty hardware component? As per Madhatters request, here are some excerpts from the log at the time (the network crashed at 20:13): /var/log/messages: Dec 2 20:01:05 graviton kernel: Firewall: *TCP_IN Blocked* IN=eth0 OUT= MAC=<stripped> SRC=<stripped> DST=<stripped> LEN=40 TOS=0x00 PREC=0x00 TTL=101 ID=256 PROTO=TCP SPT=6000 DPT=3306 WINDOW=16384 RES=0x00 SYN URGP=0 Dec 2 20:01:05 graviton kernel: Firewall: *TCP_IN Blocked* IN=eth0 OUT= MAC=<stripped> SRC=<stripped> DST=<stripped> LEN=40 TOS=0x00 PREC=0x00 TTL=100 ID=256 PROTO=TCP SPT=6000 DPT=3306 WINDOW=16384 RES=0x00 SYN URGP=0 Dec 2 20:01:05 graviton kernel: Firewall: *TCP_IN Blocked* IN=eth0 OUT= MAC=<stripped> SRC=<stripped> DST=<stripped> LEN=40 TOS=0x00 PREC=0x00 TTL=101 ID=256 PROTO=TCP SPT=6000 DPT=3306 WINDOW=16384 RES=0x00 SYN URGP=0 Dec 2 20:13:34 graviton junglediskserver: Connection to gateway failed: xGatewayTransport - Connection to gateway failed. The first three messages are simple responses to iptables rules I have set up through the LFD firewall. The last message indicates that JungleDisk, which I use for backups can no longer connect to the gateway. Apart from this, there are no interesting messages around this time. EDIT 4 dec: as per Mattdm's request, here is the output of ethtool eth0: (Please not that these are the settings that currently work. If things go wrong again, I will be sure to post this again if necessary. Settings for eth0: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised auto-negotiation: Yes Speed: 1000Mb/s Duplex: Full Port: Twisted Pair PHYAD: 1 Transceiver: internal Auto-negotiation: on Supports Wake-on: g Wake-on: d Link detected: yes As per Joris' request, here is also the output of route -n: aron@graviton [~]# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface xx.xx.xx.58 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.42 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.43 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.41 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.46 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.47 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.44 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.45 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.50 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.51 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.48 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.49 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.54 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.52 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.53 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 xx.xx.xx.0 0.0.0.0 255.255.255.192 U 0 0 0 eth0 xx.xx.xx.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0 0.0.0.0 xx.xx.xx.62 0.0.0.0 UG 0 0 0 eth0 The bottom xx.62 is my gateway. EDIT december 28th: the problem occurred again and I got the chance to compare some of the outputs of the above tests. What I found out is that arp -an returns an incomplete MAC address for my gateway (which is not under my control; the server is in a shared rack): During failure: ? (xx.xx.xx.62) at <incomplete> on eth0 After service network restart: ? (xx.xx.xx.62) at 00:00:0C:9F:F0:30 [ether] on eth0 Is this something I can fix or is it time for me to contact the data centre?

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• How to resolve "HTTP/1.1 403 Forbidden" errors from iCal/CalDAV server after upgrade to Snow Leopard Server?

  - by morgant

  We recently upgraded our Open Directory Master & Replica to Mac OS X 10.6.4 Snow Leopard Server. We had a mismatched server FQDN & LDAP Search Base/Kerberos Realm, so we exported all users & groups, created the new Open Directory Master w/matching FQDN & Search Base/Realm, reimported users & groups, and re-bound all servers & workstations to the new OD Master. At the same time as all of this, we upgraded our iCal/CalDAV server to Mac OS X 10.6.4 Snow Leopard Server. Ever since doing so, we've seen the following issues with our iCal/CalDAV server and iCal clients on both Mac OS X 10.5 Leopard & Mac OS X 10.6: If a user attempts to move or delete an event (single or repeating) that was created prior to the upgrade to 10.6 Server, they get the following error: Access to "blah" in "blah" in account "blah" is not permitted. The server responded: "HTTP/1.1 403 Forbidden" to operation CalDAVWriteEntityQueueableOperation. New users added to the directory get the following error when attempting to add their account to in iCal's preferences: The user "blah" has no configured pricipals. Confirm with your network administrator that your account has at least one CalDAV principal configured. Interestingly, we've since discovered that users seem to be able to delete individual events from an old repeating event without error, but that's a massive amount of work to get rid of a repeating event. I will note that we have not yet added an SRV record in DNS as instructed on page 19 of iCal_Server_Admin_v10.6.pdf. Further Investigation: In this particular case, a user is attempting to decline repeating events created prior to the upgrade to Snow Leopard Server. Granting the user full write access with sudo calendarserver_manage_principals --add-write-proxy users:user1 users:user2 (which did work) doesn't allow deletion of the events. Still get the usual error: Access to "blah blah" in "blah blah" in account "blah blah" is not permitted. The server responded: "HTTP/1.1 403 Forbidden" to operation CalDAVWriteEntityQueueableOperation. The error that shows up in /var/log/caldavd/error.log on the iCal Server when attempting to delete one of the events is: 2011-03-17 15:14:30-0400 [-] [caldav-8009] [PooledMemCacheProtocol,client] [twistedcaldav.extensions#info] PUT /calendars/__uids__/XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX/calendar/XXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX.ics HTTP/1.1 2011-03-17 15:14:30-0400 [-] [caldav-8009] [PooledMemCacheProtocol,client] [twistedcaldav.scheduling.implicit#error] Cannot change ORGANIZER: UID:XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX And the error in /var/log/system.log on the client is: Mar 17 15:14:30 192-168-21-169-dhcp iCal[33509]: CalDAV CalDAVWriteEntityQueueableOperation failed: status 'HTTP/1.1 403 Forbidden' request:\n\nBEGIN:VCALENDAR^M\nVERSION:2.0^M\nPRODID:-//Apple Inc.//iCal 3.0//EN^M\nCALSCALE:GREGORIAN^M\nBEGIN:VTIMEZONE^M\nTZID:US/Eastern^M\nBEGIN:DAYLIGHT^M\nTZOFFSETFROM:-0500^M\nTZOFFSETTO:-0400^M\nDTSTART:20070311T020000^M\nRRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU^M\nTZNAME:EDT^M\nEND:DAYLIGHT^M\nBEGIN:STANDARD^M\nTZOFFSETFROM:-0400^M\nTZOFFSETTO:-0500^M\nDTSTART:20071104T020000^M\nRRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU^M\nTZNAME:EST^M\nEND:STANDARD^M\nEND:VTIMEZONE^M\nBEGIN:VEVENT^M\nSEQUENCE:5^M\nDTSTART;TZID=US/Eastern:20090117T094500^M\nDTSTAMP:20081227T143043Z^M\nSUMMARY:blah blah^M\nATTENDEE;CN="First Last";CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT:urn:uuid^M\n :XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX^M\nATTENDEE;CN="First Last";CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED:mailto:user@d^M\n omain.tld^M\nEXDATE;TZID=US/Eastern:20110319T094500^M\nDTEND;TZID=US/Eastern:20090117T183000^M\nRRULE:FREQ=WEEKLY;INTERVAL=1^M\nTRANSP:OPAQUE^M\nUID:XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX^M\nORGANIZER;CN="First Last":mailto:[email protected]^M\nX-WR-ITIPSTATUSML:UNCLEAN^M\nCREATED:20110317T191348Z^M\nEND:VEVENT^M\nEND:VCALENDAR^M\n\n\n... response:\nHTTP/1.1 403 Forbidden^M\nDate: Thu, 17 Mar 2011 19:14:30 GMT^M\nDav: 1, access-control, calendar-access, calendar-schedule, calendar-auto-schedule, calendar-availability, inbox-availability, calendar-proxy, calendarserver-private-events, calendarserver-private-comments, calendarserver-principal-property-search^M\nContent-Type: text/xml^M\nContent-Length: 134^M\nServer: Twisted/8.2.0 TwistedWeb/8.2.0 TwistedCalDAV/2.5 (iCal Server v12.56.21)^M\n^M\n<?xml version='1.0' encoding='UTF-8'?><error xmlns='DAV:'>^M\n <valid-attendee-change xmlns='urn:ietf:params:xml:ns:caldav'/>^M\n</error> One thing I have noticed, and I'm not sure if this has any real effect is that in many of these pre-Snow Leopard Server migration events, the ORGANIZER is specified like the following: ORGANIZER;CN=First Last:mailto:[email protected] But newer ones are more like one of the two following: ORGANIZER;CN=First Last;[email protected];SCHEDULE-STATUS=1 ORGANIZER;CN=First Last;[email protected]:urn:uuid:XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX iCal_Server_Admin_v10.6.pdf notes that the ".db.sqlite" files are completely disposable, they're merely a performance cache and are re-built on the fly, so are safe to delete. I did delete the one for the organizer's calendars and it took longer to process the attempted event delete while it rebuilt the database, but still errored out in the end. FWIW the error is thrown by this code: https://trac.calendarserver.org/browser/CalendarServer/trunk/twistedcaldav/scheduling/implicit.py Any further suggestions? I see lots of questions about this in my Google searches, but not solutions and this is a widespread problem on our iCal Server. Now, we mostly try to get users to ignore them (hence the amount of time this question has been open), but every now and then I dig in deeper trying to find the culprit and/or solution.

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