Monthly Archives

Articles indexed in March 2010

Page 1339/2613 | < Previous Page | 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346  | Next Page >

  • Performance of std::pow - cache misses???

    - by Eamon Nerbonne
    I've been trying to optimize a numeric program of mine, and have run into something of a mystery. I'm looping over code that performs thousands of floating point operations, and just 1 call to pow nevertheless, that call takes 5% of the time... That's not necessarily a critical issue, but it is odd, so I'd like to understand what's happening. When I profiled for cache misses, VS.NET 2010RC's profiler reports that virtually all cache misses are occurring in std::pow... so... what's up with that? Is there a faster alternative? I tried powf, but that's only slightly faster; it's still responsible for an abnormal number of cache misses. Why would a basic function like pow cause cache-misses?

    Read the article

  • C# serialPort speed

    - by MarekK
    Hi I am developing some monitoring tool for some kind of protocol based on serial communication. Serial BaudRate=187,5kb I use System.IO.Ports.SerialPort class. This protocol has 4 kinds of frames. They have 1Byte,3Bytes,6Bytes, 10-255Bytes. I can work with them but I receive them too late to respond. For the beginning I receive first packed after ex. 96ms (too late), and it contains about 1000B. This means 20-50 frames (too much, too late). Later its work more stable, 3-10Bytes but it is still too late because it contains 1-2 frames. Of Course 1 frame is OK, but 2 is too late. Can you point me how can I deal with it more reliable? I know it is possible. Revision1: I tried straight way: private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e) { if (!serialPort1.IsOpen) return; this.BeginInvoke(new EventHandler(this.DataReceived)); } And Backgroud worker: And ... new Tread(Read) and... always the same. Too late, too slow. Do I have to go back to WinApi and import some kernel32.dll functions? Revision 2: this is the part of code use in the Treading way: int c = serialPort1.BytesToRead; byte[] b = new byte[c]; serialPort1.Read(b, 0, c); I guess it is some problem with stream use inside SerialPort class. Or some synchronization problem. Revision 3: I do not use both at once!! I just tried different ways. Regards MarekK

    Read the article

  • CPU/Mem/Disk utilization (average) after process has completed

    - by BassKozz
    Ubuntu Server 9.10 So there is the time command which will show you the time it took for a specific process/command to run after the command has completed. For example: :~$ time ls real 0m0.020s user 0m0.000s sys 0m0.000s I'd like to also collect the average CPU usage, Memory, and Disk (i/o) utilization after the process has completed using time (or another command if necessary). How can I accomplish this? Mainly I am using this to benchmark MySQL import performance using different innodb_buffer_pool_size settings.

    Read the article

  • Painless deployment of a Django app (port from Drupal). Do I have to switch to a VPS?

    - by Monden
    I'm about to complete porting my Drupal based community site to Django. My Drupal site is hosted at a shared hosting (Dreamhost) for last 4 years, and stability & performance has been satisfactory. The site gets around 5k unique visitors with 70-80k page views a day. This will be my first deployment of a Django application and I'm not comfortable with managing my own VPS. I use Ubuntu as a dev. server, but I don't have experience with it at the production env. I have an unrelated internal CRM app (Django) that I host with Webfaction. However security and performance isn't an issue as it's only accessed by 5 people. Unfortunately, I don't have much time to learn and maintain a VPS at this moment. I would like to know if I can host a site with this much traffic at Webfaction's shared environment? How would performance differ in comparison to Linode or Slicehost? Google AppEngine isn't an option at the moment as I'll be using my current Postgresql database.

    Read the article

  • CF64 on Server 2008x64 breaks pretty much everything else, how to fix?

    - by agarren
    I just installed CF64 on a WinServer2008x64 machine. Previously a whole array of classic ASP and ASP.Net apps were functioning, after the CF install they're not. I'm getting an http 500 on everything not coldfusion. I believe it's a mapping issue. CF seems to have dropped a wildcard handler mapping into the IIS config Module IsapiModule Notification ExecuteRequestHandler Handler AboMapperCustom-89420 Error Code 0x800700c1 The upside (if you can call it that) is that the CF install took and seems to be functioning. It appears to have dropped in

    Read the article

  • refresh screen rate ubuntu

    - by user24224
    Hello all I am having problems with the refresh rate if the screen . In the the refresh mode of the monitor in the monitor options have only one option 60Hz. I have LG 24 + ATI Radon 3870. And already installed the ati driver via ubuntu download centre. Any idea how i solve that one ? Thanks.

    Read the article

  • I cannot sync my inbox with my WM device?

    - by Miller
    I cannot sync my Outlook 2007 Inbox with my Windows Mobile device. The Inbox didn't show in sync setting in Windows Mobile Device Center. WMDC did show Calendar, Contacts, RSS Feeds and everything except Inbox. Using my mobile to receive emails ends with no error messages, but no email appears in the inbox of my mobile. What is wrong with Windows Mobile Device Center?

    Read the article

  • GetUserDefaultLocaleName() API is crashing

    - by Santhosha
    I have one application which reads user default locale in Windows Vista and above. When i tried calling the API for getting User default Locale API is crashing. Below is the code, It will be helpfull if any points the reason #include <iostream> #include <WinNls.h> #include <Windows.h> int main() { LPWSTR lpLocaleName=NULL; cout << "Calling GetUserDefaultLocaleName"; int ret = GetUserDefaultLocaleName(lpLocaleName, LOCALE_NAME_MAX_LENGTH); cout << lpLocaleName<<endl; }

    Read the article

  • First site going live real soon. Last minute questions

    - by user156814
    I am really close to finishing up on a project that I've been working on. I have done websites before, but never on my own and never a site that involved user generated data. I have been reading up on things that should be considered before you go live and I have some questions. 1) Staging... (Deploying updates without affecting users). I'm not really sure what this would entail, since I'm sure that any type of update would affect users in some way. Does this mean some type of temporary downtime for every update? can somebody please explain this and a solution to this as well. 2) Limits... I'm using the Kohana framework and I'm using the Auth module for logging users in. I was wondering if this already has some type of limit (on login attempts) built in, and if not, what would be the best way to implement this. (save attempts in database, cookie, etc.). If this is not whats meant by limits, can somebody elaborate. 3) Caching... Like I said, this is my first site built around user content. Considering that, should I cache it? 4) Back Ups... How often should I backup my (MySQL) database, and how should I back it up (MySQL export?). The site is currently up, yet not finished, if anybody wants to look at it and see if something pops out to you that should be looked at/fixed. Clashing Thoughts. If there is anything else I overlooked, thats not already in the list linked to above, please let me know. Thanks.

    Read the article

  • STL Vectors, pointers and classes

    - by anubis9
    Hey! Let's say i have 2 classes: class Class1 { public: std::vector<CustomClass3*> mVec; public: Class1(); ~Class1() { //iterate over all the members of the vector and delete the objects } }; class InitializerClass2 { private: Class1 * mPtrToClass1; public: InitializerClass2(); void Initialize() { mPtrToClass1->mVec.push_back(new CustomClass3(bla bla parameters)); } }; Will this work? Or the memory allocated in the InitializerClass2::Initialize() method might get corrupted after the method terminates? Thanks!

    Read the article

  • Mercurial Queues: combining patches

    - by Eamon Nerbonne
    I've been playing with Mercurial and mercurial queues, and now have a fairly reasonable working version. However, before I submit a patch, I'd like to take that spagetti-history and merge it into discrete, logical steps, rather than the semi-overlapping repeated do-undo-redo-slightly-differently mess it is now, if only to reduce the number of patches. How do I do that?

    Read the article

  • Programmatically talking to a Serial Port in OS X or Linux

    - by deadprogrammer
    I have a Prolite LED sign that I like to set up to show scrolling search queries from a apache logs and other fun statistics. The problem is, my G5 does not have a serial port, so I have to use a usb to serial dongle. It shows up as /dev/cu.usbserial and /dev/tty.usbserial . When i do this everything seems to be hunky-dory: stty -f /dev/cu.usbserial speed 9600 baud; lflags: -icanon -isig -iexten -echo iflags: -icrnl -ixon -ixany -imaxbel -brkint oflags: -opost -onlcr -oxtabs cflags: cs8 -parenb Everything also works when I use the serial port tool to talk to it. If I run this piece of code while the above mentioned serial port tool, everthing also works. But as soon as I disconnect the tool the connection gets lost. #!/usr/bin/python import serial ser = serial.Serial('/dev/cu.usbserial', 9600, timeout=10) ser.write("<ID01><PA> \r\n") read_chars = ser.read(20) print read_chars ser.close() So the question is, what magicks do I need to perform to start talking to the serial port without the serial port tool? Is that a permissions problem? Also, what's the difference between /dev/cu.usbserial and /dev/tty.usbserial?

    Read the article

  • C# check if a COM (Serial) port is already open

    - by TK
    Is there an easy way of programmatically checking if a serial COM port is already open/being used? Normally I would use: try { // open port } catch (Exception ex) { // handle the exception } However, I would like to programatically check so I can attempt to use another COM port or some such.

    Read the article

  • How should I Test a Genetic Algorithm

    - by James Brooks
    I have made a quite few genetic algorithms; they work (they find a reasonable solution quickly). But I have now discovered TDD. Is there a way to write a genetic algorithm (which relies heavily on random numbers) in a TDD way? To pose the question more generally, How do you test a non-deterministic method/function. Here is what I have thought of: Use a specific seed. Which wont help if I make a mistake in the code in the first place but will help finding bugs when refactoring. Use a known list of numbers. Similar to the above but I could follow the code through by hand (which would be very tedious). Use a constant number. At least I know what to expect. It would be good to ensure that a dice always reads 6 when RandomFloat(0,1) always returns 1. Try to move as much of the non-deterministic code out of the GA as possible. which seems silly as that is the core of it's purpose. Links to very good books on testing would be appreciated too.

    Read the article

  • How do I read text from a serial port?

    - by user2164
    I am trying to read data off of a Windows serial port through Java. I have the javax.comm libraries and am able to get some data but not correct data. When I read the port into a byte array and convert it to text I get a series of characters but no real text string. I have tried to specify the byte array as being both "UTF-8" and "US-ASCII". Does anyone know how to get real text out of this? Here is my code: while (inputStream.available() > 0) { int numBytes = inputStream.read(readBuffer); System.out.println("Reading from " + portId.getName() + ": "); System.out.println("Read " + numBytes + " bytes"); } System.out.println(new String(readBuffer)); System.out.println(new String(readBuffer, "UTF-8")); System.out.println(new String(readBuffer, "US-ASCII")); the output of the first three lines will not let me copy and paste (I assume because they are not normal characters). Here is the output of the Hex: 78786000e67e9e60061e8606781e66e0869e98e086f89898861878809e1e9880 I am reading from a Hollux GPS device which does output in string format. I know this for sure because I did it through C#. The settings that I am using for communication which I know are right from the work in the C# app are: Baud Rate: 9600 Databits: 8 Stop bit: 1 parity: none

    Read the article

  • How do I get Java to use the serial port in Linux?

    - by Phillip Gibb
    We make use of a java application that manages a pinpad via the serial port. This works perfectly on windows with the Sun Comm.jar, the supplied dll and the properties file. Now we are attempting to use this solution on Linux (actually it does run on various other flavours of linux out in the field) - with Ubuntu server mode. After much attempts - blood, sweat and almost tears we have this scenario: Java version 1.4.2_17 Linux - Ubuntu Comm libs - Comm3 supplied by sun with the default driver specified An external comm test shows the comm ports: /dev/ttyS0 and /dev/ttyS1 But the java application says unable to open port /dev/ttyS1 (using the RXRT files produces invalid port errors) Has anyone been able to use java 1.4.2 on linux for serial port communication and found a solution that I could apply in my scenario? greatly appreciated Phill

    Read the article

  • Is there any alternative to obfuscation to make it harder to get any string in javascript?

    - by MarceloRamires
    I use DropBox and I've had some trouble reaching to my files from other computers: I not always want to login to anything when I'm in a public computer, but I like being able to reach my stuff from wherever I am. So I've made a simple little application that when put in the public folder, ran and given the right UID, creates (still in your public folder) an HTML of all the content in the folder (including subfolders) as a tree of links. But I didn't risk loading it anywhere, since there are slightly private things in there (yes, I know that the folder's name is "PUBLIC"). So I've came up with the idea to make it a simple login page, given the right password, the rest of the page should load. brilliant!, but how? If I did this by redirecting to other HTML on the same folder, I'd still put the html link in the web history and the "url's accessed" history of the administrator. So I should generate itin the same page. I've done it. And currently the page is a textbox and a button, and only if you type in the right password (asked by the generator) the rest of the page loads. The fault is that everything (password, URL's) is easily reachable through the sourcecode. Now, assuming I only want to avoid silly people to get it all too easily, not make a bulletproof all-content-holding NSA certified website, I though about some ways to make these informations a bit harder to get. As you may have already figured, I use a streamwritter to write a .HTM file (head, loop through links, bottom), then it's extremely configurable, and I can come up with a pretty messy-but-working c# code, though my javascript knowledge is not that good. Public links in DropBox look like this: http://dl.dropbox.com/u/3045472/img.png Summarizing: How do I hide stuff (MAINLY the password, of course) in my source-code so that no bumb-a-joe that can read, use a computer and press CTRL+U can reach to my stuff too easily ? PS.: It's not that personal, if someone REALLY wants it, it could never be 100% protected, and if it was that important, I wouldnt put it in the public folder, also, if the dude really wants to get it that hard, he should deserve it. PS2.: "Use the ultra-3000'tron obfuscator!!11" is not a real answer, since my javascript is GENERATED by my c# program. PS3.: I don't want other solutions as "use a serverside application and host it somewhere to redirect and bla bla" or "compress the links in a .RAR file and put a password in it" since I'm doing this ALSO to learn, and I want the thrill of it =)

    Read the article

< Previous Page | 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346  | Next Page >