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  • High Resolution Timeouts

    - by user12607257
    The default resolution of application timers and timeouts is now 1 msec in Solaris 11.1, down from 10 msec in previous releases. This improves out-of-the-box performance of polling and event based applications, such as ticker applications, and even the Oracle rdbms log writer. More on that in a moment. As a simple example, the poll() system call takes a timeout argument in units of msec: System Calls poll(2) NAME poll - input/output multiplexing SYNOPSIS int poll(struct pollfd fds[], nfds_t nfds, int timeout); In Solaris 11, a call to poll(NULL,0,1) returns in 10 msec, because even though a 1 msec interval is requested, the implementation rounds to the system clock resolution of 10 msec. In Solaris 11.1, this call returns in 1 msec. In specification lawyer terms, the resolution of CLOCK_REALTIME, introduced by POSIX.1b real time extensions, is now 1 msec. The function clock_getres(CLOCK_REALTIME,&res) returns 1 msec, and any library calls whose man page explicitly mention CLOCK_REALTIME, such as nanosleep(), are subject to the new resolution. Additionally, many legacy functions that pre-date POSIX.1b and do not explicitly mention a clock domain, such as poll(), are subject to the new resolution. Here is a fairly comprehensive list: nanosleep pthread_mutex_timedlock pthread_mutex_reltimedlock_np pthread_rwlock_timedrdlock pthread_rwlock_reltimedrdlock_np pthread_rwlock_timedwrlock pthread_rwlock_reltimedwrlock_np mq_timedreceive mq_reltimedreceive_np mq_timedsend mq_reltimedsend_np sem_timedwait sem_reltimedwait_np poll select pselect _lwp_cond_timedwait _lwp_cond_reltimedwait semtimedop sigtimedwait aiowait aio_waitn aio_suspend port_get port_getn cond_timedwait cond_reltimedwait setitimer (ITIMER_REAL) misc rpc calls, misc ldap calls This change in resolution was made feasible because we made the implementation of timeouts more efficient a few years back when we re-architected the callout subsystem of Solaris. Previously, timeouts were tested and expired by the kernel's clock thread which ran 100 times per second, yielding a resolution of 10 msec. This did not scale, as timeouts could be posted by every CPU, but were expired by only a single thread. The resolution could be changed by setting hires_tick=1 in /etc/system, but this caused the clock thread to run at 1000 Hz, which made the potential scalability problem worse. Given enough CPUs posting enough timeouts, the clock thread could be a performance bottleneck. We fixed that by re-implementing the timeout as a per-CPU timer interrupt (using the cyclic subsystem, for those familiar with Solaris internals). This decoupled the clock thread frequency from timeout resolution, and allowed us to improve default timeout resolution without adding CPU overhead in the clock thread. Here are some exceptions for which the default resolution is still 10 msec. The thread scheduler's time quantum is 10 msec by default, because preemption is driven by the clock thread (plus helper threads for scalability). See for example dispadmin, priocntl, fx_dptbl, rt_dptbl, and ts_dptbl. This may be changed using hires_tick. The resolution of the clock_t data type, primarily used in DDI functions, is 10 msec. It may be changed using hires_tick. These functions are only used by developers writing kernel modules. A few functions that pre-date POSIX CLOCK_REALTIME mention _SC_CLK_TCK, CLK_TCK, "system clock", or no clock domain. These functions are still driven by the clock thread, and their resolution is 10 msec. They include alarm, pcsample, times, clock, and setitimer for ITIMER_VIRTUAL and ITIMER_PROF. Their resolution may be changed using hires_tick. Now back to the database. How does this help the Oracle log writer? Foreground processes post a redo record to the log writer, which releases them after the redo has committed. When a large number of foregrounds are waiting, the release step can slow down the log writer, so under heavy load, the foregrounds switch to a mode where they poll for completion. This scales better because every foreground can poll independently, but at the cost of waiting the minimum polling interval. That was 10 msec, but is now 1 msec in Solaris 11.1, so the foregrounds process transactions faster under load. Pretty cool.

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  • WCF push to client through firewall?

    - by Sire
    See also How does a WCF server inform a WCF client about changes? (Better solution then simple polling, e.g. Coment or long polling) I need to use push-technology with WCF through client firewalls. This must be a common problem, and I know for a fact it works in theory (see links below), but I have failed to get it working, and I haven't been able to find a code sample that demonstrates it. Requirements: WCF Clients connects to server through tcp port 80 (netTcpBinding). Server pushes back information at irregular intervals (1 min to several hours). Users should not have to configure their firewalls, server pushes must pass through firewalls that have all inbound ports closed. TCP duplex on the same connection is needed for this, a dual binding does not work since a port has to be opened on the client firewall. Clients sends heartbeats to server at regular intervals (perhaps every 15 mins) so server knows client is still alive. Server is IIS7 with WAS. The solution seems to be duplex netTcpBinding. Based on this information: WCF through firewalls and NATs Keeping connections open in IIS But I have yet to find a code sample that works.. I've tried combining the "Duplex" and "TcpActivation" samples from Microsoft's WCF Samples without any luck. Please can someone point me to example code that works, or build a small sample app. Thanks a lot!

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  • Why is Selenium RC so slow?

    - by Pete
    Hi. For some time I have been investigating Selenium RC in order to do functional testing of my web application. I have now found a test strategy that is so effective, that I do not want to move away from Selenium RC (after spending weeks trying to figure out a good way to validate ASP.NET validation controls). But now that my Selenium RC adventure is moving from a POC to be something that I actually use, I'm running into a problem. It is insanely slow. Executing a single test that loads a page, fills in some fields, and clicks a button takes in the magnitude of seconds to execute. When it is executing, I can easily see each individual field being filled out one at a time. Using Selenium IDE in Firefox is not that slow. I found this page, that clearly specifies that Selenium RC is slow http://selenium-grid.seleniumhq.org/how_it_works.html But why is that? Is it because the browser is polling the selenium server? If so, can this polling interval not be modified? Or is there another reason. I am not accustomed to a remote call taking a humanly noticable amount of time to execute. It is horrible that executing a few tests should take so long. I can execute my entire presentation (MVP), business, and database layer test suite (500+ tests) way quicker than it takes to run 10 tests for a single web page.

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  • Hibernate: "Field 'id' doesn't have a default value"

    - by André Neves
    Hi, all. I'm facing what I think is a simple problem with Hibernate, but can't get over it (Hibernate forums being unreachable certainly doesn't help). I have a simple class I'd like to persist, but keep getting: SEVERE: Field 'id' doesn't have a default value Exception in thread "main" org.hibernate.exception.GenericJDBCException: could not insert: [hibtest.model.Mensagem] at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103) at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91) [ a bunch more ] Caused by: java.sql.SQLException: Field 'id' doesn't have a default value [ a bunch more ] The relevant code for the persisted class is: package hibtest.model; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.Inheritance; import javax.persistence.InheritanceType; @Entity @Inheritance(strategy = InheritanceType.JOINED) public class Mensagem { protected Long id; protected Mensagem() { } @Id @GeneratedValue public Long getId() { return id; } public Mensagem setId(Long id) { this.id = id; return this; } } And the actual running code is just plain: SessionFactory factory = new AnnotationConfiguration() .configure() .buildSessionFactory(); { Session session = factory.openSession(); Transaction tx = session.beginTransaction(); Mensagem msg = new Mensagem("YARR!"); session.save(msg); tx.commit(); session.close(); } I tried some "strategies" within the GeneratedValue annotation but it just doesn't seem to work. Initializing id doesn't help either! (eg Long id = 20L). Could anyone shed some light? EDIT 2: confirmed: messing with@GeneratedValue(strategy = GenerationType.XXX) doesn't solve it SOLVED: recreating the database solved the problem

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  • C# wrapper and Callbacks

    - by fergs
    I'm in the process of writing a C# wrapper for Dallmeier Common API light (Camera & Surviellance systems) and I've never written a wrapper before, but I have used the Canon EDSDK C# wrapper. So I'm using the Canon wrapper as a guide to writing the Dallmeier wrapper. I'm currently having issues with wrapping a callback. In the API manual it has the following: dlm_connect int(unsigned long uLWindowHandle, const char * strIP, const char* strUser1, const char* strPwd1, const char* strUser2, const char* strPwd2, void (*callback)(void *pParameters, void *pResult, void *pInput), void * pInput) Arguments - ulWindowhandle - handle of the window that is passed to the ViewerSDK to display video and messages there - strUser1/2 - names of the users to log in. If only single user login is used strUser2 is - NULL - strPwd1/2 - passwords of both users. If strUser2 is NULL strPwd2 is ignored. Return This function creates a SessionHandle that has to be passed Callback pParameters will be structured: - unsigned long ulFunctionID - unsigned long ulSocketHandle, //handle to socket of the established connection - unsigned long ulWindowHandle, - int SessionHandle, //session handle of the session created - const char * strIP, - const char* strUser1, - const char* strPwd1, - const char* strUser2, - const char * strPWD2 pResult is a pointer to an integer, representing the result of the operation. Zero on success. Negative values are error codes. So from what I've read on the Net and Stack Overflow - C# uses delegates for the purpose of callbacks. So I create a my Callback function : public delegate uint DallmeierCallback(DallPparameters pParameters, IntPtr pResult, IntPtr pInput); I create the connection function [DllImport("davidapidis.dll")] public extern static int dlm_connect(ulong ulWindowHandle, string strIP, string strUser1, string strPwd1, string strUser2, string strPwd2, DallmeierCallback inDallmeierFunc And (I think) the DallPParameters as a struct : [StructLayout(LayoutKind.Sequential)] public struct DallPParameters { public ulong ulfunctionID; public ulong ulsocketHandle; public ulong ulWindowHandle; ... } All of this is in my wrapper class. Am I heading in the right direction or is this completely wrong?

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  • Segmentation fault on the server, but not local machine

    - by menachem-almog
    As stated in the title, the program is working on my local machine (ubuntu 9.10) but not on the server (linux). It's a grid hosting hosting package of godaddy. Please help.. Here is the code: #include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { long offset; FILE *io; unsigned char found; unsigned long loc; if (argc != 2) { printf("syntax: find 0000000\n"); return 255; } offset = atol(argv[1]) * (sizeof(unsigned char)+sizeof(unsigned long)); io = fopen("index.dat","rb"); fseek(io,offset,SEEK_SET); fread(&found,sizeof(unsigned char),1,io); fread(&loc,sizeof(unsigned long),1,io); if (found == 1) printf("%d\n",loc); else printf("-1\n"); fclose(io); return 0; } EDIT: It's not my program. I wish I knew enough C in order to fix it, but I'm on a deadline. This program is meant to find the first occurrence of a 7 digit number in the PI sequence, index.dat contains an huge array number = position. http://jclement.ca/fun/pi/search.cgi

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  • Practical value for concurrent-request-timeout parameter

    - by Andrei
    In the Seam Reference Guide, one can find this paragraph: We can set a sensible default for the concurrent request timeout (in ms) in components.xml: <core:manager concurrent-request-timeout="500" /> However, we found that 500 ms is not nearly enough time for most of the cases we had to deal with, especially with the severe restriction seam places on conversation access. In our application we have a combination of page scoped ajax requests (triggered by various use actions), some global scoped polling notification logic (part of the header, so included in every page) and regular links that invoke actions and/or navigate to other pages. Therefore, we get the dreaded concurrent access to conversation exception way too often, even without any significant load on the site. After researching the options for quite a bit, we ended up bumping this value to several seconds (we're debating whether to bump it up to 10s), as none of the recommended solutions seemed able to solve our issue completely (even forcing a global queue for all the ajax requests would still leave us exposed to a user deciding to click a link right when one of our polling calls was in progress). And we'd much rather have the users wait for a second or two instead of getting an error page just because they clicked a link at the wrong moment. And now to the question: is there something obvious we're missing (like a way to allow concurrent access to conversations and taking care of the needed locking ourselves, for instance :)? How do people solve this problem (ajax requests mixed with user driven interaction) in seam? Disabling all the links on the page while ajax requests are in progress (as suggested by one blog page) is really not a viable option. Any other suggestions? TIA, Andrei

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  • Create Jinja2 macros that put content in separate places

    - by Brian M. Hunt
    I want to create a table of contents and endnotes in a Jinja2 template. How can one accomplish these tasks? For example, I want to have a template as follows: {% block toc %} {# ... the ToC goes here ... #} {% endblock %} {% include "some other file with content.jnj" %} {% block endnotes %} {# ... the endnotes go here ... #} {% endblock %} Where the some other file with content.jnj has content like this: {% section "One" %} Title information for Section One (may be quite long); goes in Table of Contents ... Content of section One {% section "Two" %} Title information of Section Two (also may be quite long) <a href="#" id="en1">EndNote 1</a> <script type="text/javsacript">...(may be reasonably long) </script> {# ... Everything up to here is included in the EndNote #} Where I say "may be quite/reasonably long" I mean to say that it can't reasonably be put into quotes as an argument to a macro or global function. I'm wondering if there's a pattern for this that may accommodate this, within the framework of Jinja2. My initial thought is to create an extension, so that one can have a block for sections and end-notes, like-so: {% section "One" %} Title information goes here. {% endsection %} {% endnote "one" %} <a href="#">...</a> <script> ... </script> {% endendnote %} Then have global functions (that pass in the Jinja2 Environment): {{ table_of_contents() }} {% include ... %} {{ endnotes() }} However, while this will work for endnotes, I'd presume it requires a second pass by something for the table of contents. Thank you for reading. I'd be much obliged for your thoughts and input. Brian

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  • Segmentation Fault (C) occur on the server, but works on local machine

    - by menachem-almog
    As stated in the title, the program is working on my local machine (ubuntu 9.10) but not on the server (linux). It's a grid hosting hosting package of godaddy. Please help.. Here is the code: #include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { long offset; FILE *io; unsigned char found; unsigned long loc; if (argc != 2) { printf("syntax: find 0000000\n"); return 255; } offset = atol(argv[1]) * (sizeof(unsigned char)+sizeof(unsigned long)); io = fopen("index.dat","rb"); fseek(io,offset,SEEK_SET); fread(&found,sizeof(unsigned char),1,io); fread(&loc,sizeof(unsigned long),1,io); if (found == 1) printf("%d\n",loc); else printf("-1\n"); fclose(io); return 0; }

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  • How can I disable keep-alive on ASP.NET Web Service client requests?

    - by Matthew Brindley
    I have a few web servers behind an Amazon EC2 load balancer. I'm using TCP balancing on port 80 (rather than HTTP balancing). I have a client polling a Web Service (running on all web servers) for new items every few seconds. However, the client seems to stay connected to one server and polls that same server each time. I've tried using ServicePointManager to disable KeepAlive, but that didn't change anything. The outgoing connection still had its "connection: keep-alive" HTTP header, and the server kept the TCP connection open. I've also tried adding an override of GetWebRequest to the proxy class created by VS, which inherits from SoapHttpClientProtocol, but I still see the keep-alive header. If I kill the client's process and restart, it'll connect to a new server via the load balancer, but it'll continue polling that new server forever. Is there a way to force it to connect to a random server each time? I want the load from the one client to be spread across all of the web servers. The client is written in C# (as is the server) and uses a Web Reference (not a Service Reference), which points to the load balancer.

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  • Converting from Latitude/Longitude to Cartesian Coordinates with a World File and map image.

    - by Heath
    I have a java applet that allows users to import a jpeg and world file from the local system. The user can then "click" draw lines on the image that was imported. Each endpoint of each line contains a set of X/Y and Lat/Long values. The XY is standard java coordinate space, the applet uses an affine transform calculation with the world file to determine the lat/long for every point on the canvas. I have a requirement that allows a user to type a distance into a text field and use the arrow key to draw a line in a certain direction (Up, Down, Left, Right) from a single selected point on the screen. I know how to determine the lat/long of a point given a source lat/long, distance, and bearing. So a user types "100" in the text field and presses the Right arrow key a line should be drawn 100 feet to the right from the currently selected point. My issue is I don't know how to convert the distance( which is in feet ) into the distance in pixels. This would then tell my where to plot the point.

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  • How should I implement reverse AJAX in a Django application?

    - by Carson Myers
    How should I implement reverse AJAX when building a chat application in Django? I've looked at Django-Orbited, and from my understanding, this puts a comet server in front of the HTTP server. This seems fine if I'm just running the Django development server, but how does this work when I start running the application from mod_wsgi? How does having the orbited server handling every request scale? Is this the correct approach? I've looked at another approach (long polling) that seems like it would work, although I'm not sure what all would be involved. Would the client request a page that would live in its own thread, so as not to block the rest of the application? Would it even block? Wouldn't the script requested by the client have to continuously poll for information? Which of the approaches is more proper? Which is more portable, scalable, sane, etc? Are there other good approaches to this (aside from the client polling for messages) that I have overlooked?

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  • Passing VB Callback function to C dll - noob is stuck.

    - by WaveyDavey
    Callbacks in VB (from C dll). I need to pass a vb function as a callback to a c function in a dll. I know I need to use addressof for the function but I'm getting more and more confused as to how to do it. Details: The function in the dll that I'm passing the address of a callback to is defined in C as : PaError Pa_OpenStream( PaStream** stream, const PaStreamParameters *inputParameters, const PaStreamParameters *outputParameters, double sampleRate, unsigned long framesPerBuffer, PaStreamFlags streamFlags, PaStreamCallback *streamCallback, void *userData ); where the function is parameter 7, *streamCallback. The type PaStreamCallback is defines thusly: typedef int PaStreamCallback( const void *input, void *output, unsigned long frameCount, const PaStreamCallbackTimeInfo* timeInfo, PaStreamCallbackFlags statusFlags, void *userData ); In my vb project I have: Private Declare Function Pa_OpenStream Lib "portaudio_x86.dll" _ ( ByVal stream As IntPtr _ , ByVal inputParameters As IntPtr _ , ByVal outputParameters As PaStreamParameters _ , ByVal samprate As Double _ , ByVal fpb As Double _ , ByVal paClipoff As Long _ , ByVal patestCallBack As IntPtr _ , ByVal data As IntPtr) As Integer (don't worry if I've mistyped some of the other parameters, I'll get to them later! Let's concentrate on the callback for now.) In module1.vb I have defined the callback function: Function MyCallback( ByVal inp As Byte, _ ByVal outp As Byte, _ ByVal framecount As Long, _ ByVal pastreamcallbacktimeinfo As Byte, _ ByVal pastreamcallbackflags As Byte, _ ByVal userdata As Byte) As Integer ' do clever things here End Function The external function in the dll is called with err = Pa_OpenStream( ptr, _ nulthing, _ outputParameters, _ SAMPLE_RATE, _ FRAMES_PER_BUFFER, _ clipoff, _ AddressOf MyCallback, _ dataptr) This is broken in the declaration of the external function - it doesn't like the type IntPtr as a function pointer for AddressOf. Can anyone show me how to implement passing this callback function please ? Many thanks David

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  • PHP REGEX - text to array by preg_split at line break

    - by aSeptik
    Hi All! EDITED: need help on split Array array example: $text = array ( [0] => TEXT1:some normal text TEXT2:some long text here, and so on... sometimes i'm breaking down and... TEXT3:some normal text TEXT4:some normal text [1] => TEXT1:some normal text TEXT2:some long text here, and so on... sometimes i'm breaking down and... TEXT3:some normal text TEXT4:some normal text ) ok, now by using preg_split( '#\n(?!s)#' , $text ); i get [0] => Array ( [0] => some normal text [1] => some long text here, and so on... sometimes [2] => some normal text [3] => some normal text ) As you can see the [1] Element of the Array is cutted off! i want keep this line entirely: some long text here, and so on... sometimes i'm breaking down and... what Regex can get the entire line and also split at line break!?

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  • setInterval alternative

    - by spyder
    Hi folks, In my app I am polling the webserver for messages every second and displaying them in the frontend. I use setInterval to achieve this. However as long as the user stays on that page the client keeps polling the server with requests even if there is no data. The server does give an indication when no more messages are being generated by setting a variable. I thought of using this variable to clearInterval and stop the timer but that didn't work. What else can I use in this situation? I am using jquery and django. Here is my code: jquery: var refresh = setInterval( function () { var toLoad = '/myMonitor'+' #content'; $('#content').load(toLoad).show(); }, 1000); // refresh every 1000 milliseconds }); html: div id=content is here I can access the django variable for completion in html with each refresh. How can I set clearInterval if at all ? Note: stack overflow does not let me put is &gt &lt so html is incomplete Thanks

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  • Threads, Sockets, and Designing Low-Latency, High Concurrency Servers

    - by lazyconfabulator
    I've been thinking a lot lately about low-latency, high concurrency servers. Specifically, http servers. http servers (fast ones, anyway) can serve thousands of users simultaneously, with very little latency. So how do they do it? As near as I can tell, they all use events. Cherokee and Lighttpd use libevent. Nginx uses it's own event library performing much the same function of libevent, that is, picking a platform optimal strategy for polling events (like kqueue on *bsd, epoll on linux, /dev/poll on Solaris, etc). They all also seem to employ a strategy of multiprocess or multithread once the connection is made - using worker threads to handle the more cpu intensive tasks while another thread continues to listen and handle connections (via events). This is the extent of my understanding and ability to grok the thousand line sources of these applications. What I really want are finer details about how this all works. In examples of using events I've seen (and written) the events are handling both input and output. To this end, do the workers employ some sort of input/output queue to the event handling thread? Or are these worker threads handling their own input and output? I imagine a fixed amount of worker threads are spawned, and connections are lined up and served on demand, but how does the event thread feed these connections to the workers? I've read about FIFO queues and circular buffers, but I've yet to see any implementations to work from. Are there any? Do any use compare-and-swap instructions to avoid locking or is locking less detrimental to event polling than I think? Or have I misread the design entirely? Ultimately, I'd like to take enough away to improve some of my own event-driven network services. Bonus points to anyone providing solid implementation details (especially for stuff like low-latency queues) in C, as that's the language my network services are written in.

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  • ftp .net getdirectory size

    - by Xaver
    hi i write method which must to know that is size of specified directory i get response from server which contains flags of file name size and other info and on the different ftp servers format of answer is different how to know format of answer? unsigned long long GetFtpDirSize(String^ ftpDir) { unsigned long long size = 0; int j = 0; StringBuilder^ result = gcnew StringBuilder(); StreamReader^ reader; FtpWebRequest^ reqFTP; reqFTP = (FtpWebRequest^)FtpWebRequest::Create(gcnew Uri(ftpDir)); reqFTP->UseBinary = true; reqFTP->Credentials = gcnew NetworkCredential("anonymous", "123"); reqFTP->Method = WebRequestMethods::Ftp::ListDirectoryDetails; reqFTP->KeepAlive = false; reqFTP->UsePassive = false; try { WebResponse^ resp = reqFTP->GetResponse(); Encoding^ code; code = Encoding::GetEncoding(1251); reader = gcnew StreamReader(resp->GetResponseStream(), code); String^ line = reader->ReadToEnd(); array<Char>^delimiters = gcnew array<Char>{ '\r', '\n' }; array<Char>^delimiters2 = gcnew array<Char>{ ' ' }; array<String^>^words = line->Split(delimiters, StringSplitOptions::RemoveEmptyEntries); array<String^>^DetPr; System::Collections::IEnumerator^ myEnum = words->GetEnumerator(); while ( myEnum->MoveNext() ) { String^ word = safe_cast<String^>(myEnum->Current); DetPr = word->Split(delimiters2); } }

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  • setcontext and makecontext to call a generic function pointer

    - by Simone Margaritelli
    In another question i had the problem to port the code unsigned long stack[] = { 1, 23, 33, 43 }; /* save all the registers and the stack pointer */ unsigned long esp; asm __volatile__ ( "pusha" ); asm __volatile__ ( "mov %%esp, %0" :"=m" (esp)); for( i = 0; i < sizeof(stack); i++ ){ unsigned long val = stack[i]; asm __volatile__ ( "push %0" :: "m"(val) ); } unsigned long ret = function_pointer(); /* restore registers and stack pointer */ asm __volatile__ ( "mov %0, %%esp" :: "m" (esp) ); asm __volatile__ ( "popa" ); To a 64bit platform and many guys told me i should use the setcontext and makecontext functions set instead due to the calling conversion differences between 32 and 64 bits and portability issues. Well, i really can't find any useful documentation online, or at least not the kind i need to implement this, so, how can i use those functions to push arguments onto the stack, call a generic function pointer, obtain the return value and then restore the registers?

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  • Java Performance measurement

    - by portoalet
    Hi, I am doing some Java performance comparison between my classes, and wondering if there is some sort of Java Performance Framework to make writing performance measurement code easier? I.e, what I am doing now is trying to measure what effect does it have having a method as "synchronized" as in PseudoRandomUsingSynch.nextInt() compared to using an AtomicInteger as my "synchronizer". So I am trying to measure how long it takes to generate random integers using 3 threads accessing a synchronized method looping for say 10000 times. I am sure there is a much better way doing this. Can you please enlighten me? :) public static void main( String [] args ) throws InterruptedException, ExecutionException { PseudoRandomUsingSynch rand1 = new PseudoRandomUsingSynch((int)System.currentTimeMillis()); int n = 3; ExecutorService execService = Executors.newFixedThreadPool(n); long timeBefore = System.currentTimeMillis(); for(int idx=0; idx<100000; ++idx) { Future<Integer> future = execService.submit(rand1); Future<Integer> future1 = execService.submit(rand1); Future<Integer> future2 = execService.submit(rand1); int random1 = future.get(); int random2 = future1.get(); int random3 = future2.get(); } long timeAfter = System.currentTimeMillis(); long elapsed = timeAfter - timeBefore; out.println("elapsed:" + elapsed); } the class public class PseudoRandomUsingSynch implements Callable<Integer> { private int seed; public PseudoRandomUsingSynch(int s) { seed = s; } public synchronized int nextInt(int n) { byte [] s = DonsUtil.intToByteArray(seed); SecureRandom secureRandom = new SecureRandom(s); return ( secureRandom.nextInt() % n ); } @Override public Integer call() throws Exception { return nextInt((int)System.currentTimeMillis()); } } Regards

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  • permutations gone wrong

    - by vbNewbie
    I have written code to implement an algorithm I found on string permutations. What I have is an arraylist of words ( up to 200) and I need to permutate the list in levels of 5. Basically group the string words in fives and permutated them. What I have takes the first 5 words generates the permutations and ignores the rest of the arraylist? Any ideas appreciated. Private Function permute(ByVal chunks As ArrayList, ByVal k As Long) As ArrayList ReDim ItemUsed(k) pno = 0 Permutate(k, 1) Return chunks End Function Private Shared Sub Permutate(ByVal K As Long, ByVal pLevel As Long) Dim i As Long, Perm As String Perm = pString ' Save the current Perm ' for each value currently available For i = 1 To K If Not ItemUsed(i) Then If pLevel = 1 Then pString = chunks.Item(i) 'pString = inChars(i) Else pString = pString & chunks.Item(i) 'pString += inChars(i) End If If pLevel = K Then 'got next Perm pno = pno + 1 SyncLock outfile outfile.WriteLine(pno & " = " & pString & vbCrLf) End SyncLock outfile.Flush() Exit Sub End If ' Mark this item unavailable ItemUsed(i) = True ' gen all Perms at next level Permutate(K, pLevel + 1) ' Mark this item free again ItemUsed(i) = False ' Restore the current Perm pString = Perm End If Next K above is = to 5 for the number of words in one permutation but when I change the for loop to the arraylist size I get an error of index out of bounds

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  • Efficient splitting of elements in a field

    - by Gary
    I have a field in a text file exported from a database. The field contains addresses but sometimes they are quite long and the database allows them to contain multiple lines. When exported, the newline character gets replaced with a dollar sign like this: first part of very long address$second part of very long address$third part of very long address Not every address has multiple lines and no address contains more than three lines. The length of each line is variable. I'm massaging the data for import into MS Access which is used for a mailmerge. I want to split the field on the $ sign if it's there but if the field only contains 1 line, I want to set my two extra output fields to a zero length string so that I don't wind up with blank lines in the address when it gets printed. I have an awk file that's working correctly on all the other data in the textfile but I need to get this last bit working. I tried the below code. Aside from the fact that I get a syntax error at the else, I'm not sure this is a good way to do what I want. This is being done with gawk on Windows. BEGIN { FS = "|" } $1 != "HEADER" { if ($6 ~ /\$/) split($6, arr, "$") address = arr[1] addresstwo = arr[2] addressthree = arr[3] addressLength = length(address) addressTwoLength = length(addresstwo) addressThreeLength = length(addressthree) else { address = $6 addressLength = length($6) addresstwo = "" addressTwoLength = length(addresstwo) addressthree = "" addressThreeLength = length(addressthree) } printf("%*s\t%*s\t\%*s\n", addressLength, address, addressTwoLength, addresstwo, addressThreeLength, addressthree) }

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  • Python import error: Symbol not found, but the symbol <s>is</s> *is not* present in the file

    - by Autopulated
    I get this error when I try to import ssrc.spread: ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/ssrc/_spread.so, 2): Symbol not found: __ZN17ssrcspread_v1_0_67Mailbox11ZeroTimeoutE The file in question (_spread.so) includes the symbol: $ nm _spread.so | grep _ZN17ssrcspread_v1_0_67Mailbox11ZeroTimeoutE U __ZN17ssrcspread_v1_0_67Mailbox11ZeroTimeoutE U __ZN17ssrcspread_v1_0_67Mailbox11ZeroTimeoutE (twice because the file is a fat ppc/x86 binary) EDIT: okay, as James points out, the U means that the symbol is undefined but required by the object file. With some more digging I've noticed (where I should have looked first...) these linker errors during compilation: CC=g++ CXX=g++ g++-4.0 -arch ppc -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -fno-strict-aliasing -fno-common -dynamic -DNDEBUG -O3 -I../.. -I../.. -I/usr/local/include -I/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6 -O2 -I/usr/local/include -std=c++98 -pipe -fno-gnu-keywords -fvisibility-inlines-hidden -o SsrcSpread.o -c SsrcSpread.cc CC=g++ CXX=g++ /bin/sh ../../libtool --tag=CXX --mode=link g++-4.0 -arch ppc -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -bundle -undefined dynamic_lookup -F/Library/Frameworks -framework Python \ -pthread -D_REENTRANT -pedantic -Wall -Wno-long-long -Winline -Woverloaded-virtual -Wold-style-cast -Wsign-promo -L../../ssrc -lssrcspread -L/usr/local/lib -ltspread-core -o _spread.so SsrcSpread.o mkdir .libs g++-4.0 -arch ppc -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -bundle -undefined dynamic_lookup -F/Library/Frameworks -framework Python -pthread -D_REENTRANT -pedantic -Wall -Wno-long-long -Winline -Woverloaded-virtual -Wold-style-cast -Wsign-promo -o _spread.so SsrcSpread.o -Wl,-bind_at_load -L/Dev/libssrcspread-1.0.6/ssrc /Dev/libssrcspread-1.0.6/ssrc/.libs/libssrcspread.a -L/usr/local/lib -ltspread-core ld: warning: in ~/Dev/libssrcspread-1.0.6/ssrc/.libs/libssrcspread.a, file was built for unsupported file format which is not the architecture being linked (ppc) ld: warning: in /Developer/SDKs/MacOSX10.4u.sdk/usr/local/lib/libtspread-core.dylib, file was built for unsupported file format which is not the architecture being linked (ppc) ld: warning: in /Dev/libssrcspread-1.0.6/ssrc/.libs/libssrcspread.a, file was built for unsupported file format which is not the architecture being linked (i386) ld: warning: in /Developer/SDKs/MacOSX10.4u.sdk/usr/local/lib/libtspread-core.dylib, file was built for unsupported file format which is not the architecture being linked (i386) I'm also not entirely sure that the 10.4 sdk is the right one for compiling python modules (but switching to 10.6 didn't seem to help).

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  • Float a div in top right corner without overlapping sibling header

    - by Maxime R.
    Having a div and a h1 inside a section, how do i float the div in the top right corner without overlapping the text of the header ? The HTML code is the following: <section> <h1>some long long long long header, a whole line, 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6</h1> <div><button>button</button></div> </section> I tried an absolute position relative to the parent but the text is overlapped, http://jsfiddle.net/FnpS8/2/ Using this CSS code: section { position: relative; } h1 { display: inline; } div { position: absolute; top: 0; right: 0; } I tried floating the div to the right but it doesn't remain in the top right corner, http://jsfiddle.net/P6xCw/2/ Using this CSS code: h1 { display: inline; } div { float: right; } ? I know there is a lot of similar questions but I couldn't find one solving this case.

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  • Google Maps, marker info window won't show up ?

    - by user296516
    Hi guys, I have written this code that loops through an array of lat/long coordinates and places a marker at each of the coordinate. Everything forks fine, exempt the info window won't appear once the marker is clicked. var ExpTowerIcon = new GIcon(); ExpTowerIcon.image = "tower.png"; ExpTowerIcon.iconSize = new GSize(75, 75); ExpTowerIcon.iconAnchor = new GPoint(37, 65); ExpTowerIcon.infoWindowAnchor = new GPoint(37, 20); var marker=new Array(); for ( i=0 ; i < lat.length ; i++ ) { var MarkerPoint = new GLatLng(lat[i],long[i]); marker[i] = new GMarker(MarkerPoint,{icon:ExpTowerIcon}) map.addOverlay( marker[i] ); GEvent.addListener( marker[i] , 'click', function() { marker[i].openInfoWindowHtml('Hello!') ; }); var polyline = new GPolyline([ new GLatLng(lat[i],long[i]) , new GLatLng(lat[i+1],long[i+1]) ], "#ff0000", 5); map.addOverlay(polyline); } Any ideas? Thanks!

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  • android numberformat exception

    - by asifkt
    my application shows this number format exception errror while running. 1 0-22 11:09:06.095: WARN/System.err(290): at java.lang.Long.parseLong(Long.java:330) 10-22 11:09:06.095: WARN/System.err(290): at java.lang.Long.parseLong(Long.java:307) 10-22 11:09:06.105: WARN/System.err(290): at com.htc.socialnetwork.facebook.FacebookUtils.getSyncInterval(FacebookUtils.java:54) 10-22 11:09:06.105: WARN/System.err(290): at com.htc.socialnetwork.facebook.remote.FacebookReceiver.getSyncInterval(FacebookReceiver.java:269) 10-22 11:09:06.105: WARN/System.err(290): at com.htc.socialnetwork.facebook.remote.FacebookReceiver.onReceive(FacebookReceiver.java:196) 10-22 11:09:06.105: WARN/System.err(290): at android.app.ActivityThread.handleReceiver(ActivityThread.java:2751) 10-22 11:09:06.105: WARN/System.err(290): at android.app.ActivityThread.access$3100(ActivityThread.java:126) 10-22 11:09:06.105: WARN/System.err(290): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1982) 10-22 11:09:06.105: WARN/System.err(290): at android.os.Handler.dispatchMessage(Handler.java:99) 10-22 11:09:06.105: WARN/System.err(290): at android.os.Looper.loop(Looper.java:123) 10-22 11:09:06.105: WARN/System.err(290): at android.app.ActivityThread.main(ActivityThread.java:4603) 10-22 11:09:06.105: WARN/System.err(290): at java.lang.reflect.Method.invokeNative(Native Method) 10-22 11:09:06.105: WARN/System.err(290): at java.lang.reflect.Method.invoke(Method.java:521) 10-22 11:09:06.105: WARN/System.err(290): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 10-22 11:09:06.105: WARN/System.err(290): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 10-22 11:09:06.115: WARN/System.err(290): at dalvik.system.NativeStart.main(Native Method) anybody please help me to get the reason for this error

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