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  • Perl Threads with binmode

    - by jAndy
    Hi Folks, this call my $th = threads->create(\&print, "Hello thread World!\n"); $th->join(); works fine. But as soon as I add binmode(STDOUT, ":encoding(ISO-8859-1)"); to my script file, I get an error like "segmentation fault", "access denied". What is wrong to define an encoding type when trying to call a perl thread? Kind Regards --Andy

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  • How to learn about Threads, Especially in Java.

    - by Javed Ahamed
    I have always been kind of confused by threads, and my class right now makes heavy use of them. We are using java.util.concurrent but I don't even really get the basics. UpDownLatch, Futures, Executors; these words just fly over my head. Can you guys suggest any resources to help learn what I need from the ground up? Thanks a lot in advance!

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  • Queuing methods to be run on an object by different threads in Python

    - by Ben
    Let's say I have an object who's class definition looks like: class Command: foo = 5 def run(self, bar): time.sleep(1) self.foo = bar return self.foo If this class is instantiated once, but different threads are hitting its run method (via an HTTP request, handled separately) passing in different args, what is the best method to queue them? Can this be done in the class definition itself?

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  • Using events in threads between processes - C

    - by Jamie Keeling
    Hello all! I have an application consisting of two windows, one communicates to the other and sends it a struct constaining two integers (In this case two rolls of a dice). I will be using events for the following circumstances: Process a sends data to process b, process b displays data Process a closes, in turn closing process b Process b closes a, in turn closing process a I have noticed that if the second process is constantly waiting for the first process to send data then the program will be just sat waiting, which is where the idea of implementing threads on each process occurred and I have started to implement this already. The problem i'm having is that I don't exactly have a lot of experience with threads and events so I'm not sure of the best way to actually implement what I want to do. Following is a small snippet of what I have so far in the producer application; Create thread: case IDM_FILE_ROLLDICE: { hDiceRoll = CreateThread( NULL, // lpThreadAttributes (default) 0, // dwStackSize (default) ThreadFunc(hMainWindow), // lpStartAddress NULL, // lpParameter 0, // dwCreationFlags &hDiceID // lpThreadId (returned by function) ); } break; The data being sent to the other process: DWORD WINAPI ThreadFunc(LPVOID passedHandle) { HANDLE hMainHandle = *((HANDLE*)passedHandle); WCHAR buffer[256]; LPCTSTR pBuf; LPVOID lpMsgBuf; LPVOID lpDisplayBuf; struct diceData storage; HANDLE hMapFile; DWORD dw; //Roll dice and store results in variable storage = RollDice(); hMapFile = CreateFileMapping( (HANDLE)0xFFFFFFFF, // use paging file NULL, // default security PAGE_READWRITE, // read/write access 0, // maximum object size (high-order DWORD) BUF_SIZE, // maximum object size (low-order DWORD) szName); // name of mapping object if (hMapFile == NULL) { dw = GetLastError(); MessageBox(hMainHandle,L"Could not create file mapping object",L"Error",MB_OK); return 1; } pBuf = (LPTSTR) MapViewOfFile(hMapFile, // handle to map object FILE_MAP_ALL_ACCESS, // read/write permission 0, 0, BUF_SIZE); if (pBuf == NULL) { MessageBox(hMainHandle,L"Could not map view of file",L"Error",MB_OK); CloseHandle(hMapFile); return 1; } CopyMemory((PVOID)pBuf, &storage, (_tcslen(szMsg) * sizeof(TCHAR))); //_getch(); MessageBox(hMainHandle,L"Completed!",L"Success",MB_OK); UnmapViewOfFile(pBuf); return 0; } I'm trying to find out how I would integrate an event with the threaded code to signify to the other process that something has happened, I've seen an MSDN article on using events but it's just confused me if anything, I'm coming up on empty whilst searching on the internet too. Thanks for any help Edit: I can only use the Create/Set/Open methods for events, sorry for not mentioning it earlier.

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  • BSoD when creating threads

    - by Behrooz
    I am trying to create +5 threads synchronously so there shouldn't be any concurrency error. Code: System.Threading.Thread t = new System.Threading.Thread(proc); t.Start();//==t.BlueScreen(); t.Join(); Is darkness a feature ? I am doing something wrong? OS:Microsoft windows vista(unfortunately) x64 Language:C# 3.0|4.0 .Net version:3.5|4

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  • Understanding java's native threads and the jvm

    - by Moev4
    I understand that the jvm is itself an application that turns the bytecode of the java executable into native machine code, but when using native threads I have some questions that I just cannot seem to answer. Does every thread create their own instance of the jvm to handle their particular execution? If not then does the jvm have to have some way to schedule which thread it will handle next, if so wouldn't this render the multi-threaded nature of java useless since only one thread can be ran at a time?

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  • C threads question

    - by Nadeem
    Write program that has two threads one is reading numbers from the user and the other is printing them such that the first thread reads a new number only after it has been printed by the second thread. Declare one global varaible to use for reading and printing.

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  • Critical Threads Optimization

    - by Rafael Vanoni
    Background One of the more common issues we've been seeing in the field is the growing difficulty in optimizing performance of multi-threaded applications. A good portion of this difficulty is due to the increasing complexity of modern processors that present various degrees of sharing relationships between hardware components. Take any current CMT processor and you'll find any number of CPUs sharing execution pipelines, floating point units, caches, etc. Consequently, applying the traditional recipe of one software thread for each CPU will have varying degrees of success, according to the layout of the underlying hardware. On top of this increasing complexity we've also seen processors with features that aim at dynamically resourcing software threads according to their utilization. Intel's Turbo Boost allows processors to increase their operating frequency if there is enough thermal headroom available and the processor isn't fully utilized. More recently, the SPARC T4 processor introduced dynamic threading, allowing each core to dynamically allocate more resources to its active CPUs. Both cases are in essence recognizing that current processors will be running a wide mix of workloads, some will be designed for throughput, others for low latency. The hardware is providing mechanisms to dynamically resource threads according to their runtime behavior. We're very aware of these challenges in Solaris, and have been working to provide the best out of box performance while providing mechanisms to further optimize applications when necessary. The Critical Threads Optimzation was introduced in Solaris 10 8/11 and Solaris 11 as one such mechanism that allows customers to both address issues caused by contention over shared hardware resources and explicitly take advantage of features such as T4's dynamic threading. What it is The basic idea is to allow performance critical threads to execute with more exclusive access to hardware resources. For example, when deploying an application that implements a producer/consumer model, it'll likely be advantageous to give the producer more exclusive access to the hardware instead of having it competing for resources with all the consumers. In the case of a T4 based system, we may want to have a producer running by itself on a single core and create one consumer for each of the remaining CPUs. With the Critical Threads Optimization we're extending the semantics of scheduling priorities (which thread should run first) to include priority over shared resources (which thread should have more "space"). Now the scheduler will not only run higher priority threads first: it will also provide them with more exclusive access to hardware resources if they are available. How does it work ? Using the previous example in Solaris 11, all you'd have to do would be to place the producer in the Fixed Priority (FX) scheduling class at priority 60, or in the Real Time (RT) class at any priority and Solaris will try to give it more "hardware space". On both Solaris 10 8/11 and Solaris 11 this can be achieved through the existing priocntl(1,2) and priocntlset(2) interfaces. If your application already assigns these priorities to performance critical threads, there's no additional step you need to take. One important aspect of this optimization is that it requires some level of idleness in the system, either as a result of sizing the application before hand or through periods of transient idleness during runtime. If the system is fully committed, the scheduler will put all the available CPUs to work.Best practices If you're an application developer, we encourage you to look into assigning the right priorities for the different threads in your application. Solaris provides different scheduling classes (Time Share, Interactive, Fair Share, Fixed Priority and Real Time) that offer different policies and behaviors. It is not always simple to figure out which set of threads are critical to the performance of a workload, and it may not always be feasible to take advantage of this optimization, but we believe that this can be correctly (and safely) done during development. Overall, the out of box performance in Solaris should meet your workload's requirements. If you are looking into that extra bit of performance, then the Critical Threads Optimization may be what you're looking for.

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  • Using device variable by multiple threads on CUDA

    - by ashagi
    I am playing around with cuda. At the moment I have a problem. I am testing a large array for particular responses, and when I get the response, I have to copy the data onto another array. For example, my test array of 5 elements looks like this: [ ][ ][v1][ ][ ][v2] Result must look like this: [v1][v2] The problem is how do I calculate the address of the second array to store the result? All elements of the first array are checked in parallel. I am thinking to declare a device variable int addr = 0. Every time I find a response, I will increment the addr. But I am not sure about that because it means that addr may be accessed by multiple threads at the same time. Will that cause problems? Or will the thread wait until another thread finishes using that variable?

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  • C# Abort()ing threads on exit for a Form

    - by Gio Borje
    So far I have this code run when the X button is clicked, but I'm not sure if this is the correct way to terminate threads on a form on exit. Type t = this.GetType(); foreach (PropertyInfo pi in t.GetProperties()) { if (pi.GetType() == typeof(Thread)) { MethodInfo mi = pi.GetType().GetMethod("Abort"); mi.Invoke(null, new object[] {}); } } I keep getting this error: "An attempt has been made to free an RCW that is in use. The RCW is in use on the active thread or another thread. Attempting to free an in-use RCW can cause corruption or data loss."

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  • Have threads run indefinitely in a java application

    - by TP
    I am trying to program a game in which I have a Table class and each person sitting at the table is a separate thread. The game involves the people passing tokens around and then stopping when the party chime sounds. how do i program the run() method so that once I start the person threads, they do not die and are alive until the end of the game One solution that I tried was having a while (true) {} loop in the run() method but that increases my CPU utilization to around 60-70 percent. Is there a better method?

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  • Java threads problem

    - by MyNameIs
    Hi! I have a problem with java threads: public class MyClass{ public void Core(){ runTools(); //here I would like to call runTools() method } public void runTools(){ final String run_tool ="cmd.exe /C sources.exe"; Runnable doRun = new Runnable() { public void run() { try { Process tool_proc = Runtime.getRuntime().exec(run_tool); } catch (IOException e) { e.printStackTrace(); } } }; Thread th = new Thread(doRun); th.start(); } } If I do this, then I don't know why, but the thread doesn't work. Please give me some ideas to create a thread. I have already been seen lots of examples, but I should some code such as my example here. Thanks!

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  • two android threads and not synchronized data

    - by Sponge
    i have a (perhaps stupid) question: im using 2 threads, one is writing floats and one is reading this floats permanently. my question is, what could happen worse when i dont synchronize them? it would be no problem if some of the values would not be correct because they switch just a little every write operation. im running the application this way at the moment and dont have any problems so i want to know what could happen worse? a read/write conflict would cause a number like 12345 which is written to 54321 and red at the same time appear for example as 54345 ? or could happen something worse? (i dont want to use synchronization to keep the code as fast as possible)

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  • Problem with basic program using Boost Threads in c++

    - by Eternal Learner
    I have a simple program which creates and executes as thread using boost threads in c++. #include<boost/thread/thread.hpp> #include<iostream> void hello() { std::cout<<"Hello, i am a thread"<<std::endl; } int main() { boost::thread th1(&hello); th1.join(); } The compiler throws an error against the th1.join() line. It says " Multiple markers at this line - undefined reference to `boost::thread::join()' - undefined reference to `boost::thread::~thread()' "

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  • Best approach to synchronising properties across threads

    - by user290796
    Hi, I'm looking for some advice on the best approach to synchronising access to properties of an object in C++. The application has an internal cache of objects which have 10 properties. These objects are to be requested in sets which can then have their properties modified and be re-saved. They can be accessed by 2-4 threads at any given time but access is not intense so my options are: Lock the property accessors for each object using a critical section. This means lots of critical sections - one for each object. Return copies of the objects when requested and have an update function which locks a single critical section to update the object properties when appropriate. I think option 2 seems the most efficient but I just want to see if I'm missing a hidden 3rd option which would be more appropriate. Thanks, J

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  • Long running operations (threads) in a web (asp.net) environment

    - by rrejc
    I have an asp.net (mvc) web site. As the part of the functions I will have to support some long running operations, for example: Initiated from user: User can upload (xml) file to the server. On the server I need to extract file, do some manipulation (insert into the db) etc... This can take from one minute to ten minutes (or even more - depends on file size). Of course I don't want to block the request when the import is running , but I want to redirect user to some progress page where he will have a chance to watch the status, errors or even cancel the import. This operation will not be frequently used, but it may happen that two users at the same time will try to import the data. It would be nice to run the imports in parallel. At the beginning I was thinking to create a new thread in the iis (controller action) and run the import in a new thread. But I am not sure if this is a good idea (to create working threads on a web server). Should I use windows services or any other approach? Initiated from system: - I will have to periodically update lucene index with the new data. - I will have to send mass emails (in the future). Should I implement this as a job in the site and run the job via Quartz.net or should I also create a windows service or something? What are the best practices when it comes to running site "jobs"? Thanks!

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  • Threads in Java

    - by owca
    I've created simple program to test Threads in Java. I'd like it to print me numbers infinitely, like 123123123123123. Dunno why, but currently it stops after one cycle finishing 213 only. Anyone knows why ? public class Main { int number; public Main(int number){ } public static void main(String[] args) { new Infinite(2).start(); new Infinite(1).start(); new Infinite(3).start(); } } class Infinite extends Thread { static int which=1; static int order=1; int id; int number; Object console = new Object(); public Infinite(int number){ id = which; which++; this.number = number; } @Override public void run(){ while(1==1){ synchronized(console){ if(order == id){ System.out.print(number); order++; if(order >= which){ order = 1; } try{ console.notifyAll(); console.wait(); } catch(Exception e) {} } else { try{ console.notifyAll(); console.wait(); } catch(Exception e) {} } } try{Thread.sleep(0);} catch(Exception e) {} } } }

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  • make a thread which recieves values from other threads

    - by farteaga88
    This program in Java creates a list of 15 numbers and creates 3 threads to search for the maximum in a given interval. I want to create another thread that takes those 3 numbers and get the maximum. but i don't know how to get those values in the other thread. public class apple implements Runnable{ String name; int time, number, first, last, maximum; int[] array = {12, 32, 54 ,64, 656, 756, 765 ,43, 34, 54,5 ,45 ,6 , 5, 65}; public apple(String s, int f, int l){ name = s; first = f; last = l; maximum = array[0]; } public void run(){ try{ for(int i = first; i < last; i++ ) { if(maximum < array[i]) { maximum = array[i]; } } System.out.println("Thread"+ name + "maximum = " + maximum); }catch(Exception e){} } public static void main(String[] args){ Thread t1 = new Thread(new apple("1 ", 0, 5)); Thread t2 = new Thread(new apple("2 ", 5, 10 )); Thread t3 = new Thread(new apple("3 ", 10, 15)); try{ t1.start(); t2.start(); t3.start(); }catch(Exception e){} } }

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  • In threads, WaitForMultipleObjects never returns if set to INFINITE

    - by AKN
    Let say I have three thread handles HandleList[0] = hThread1; HandleList[1] = hThread2; HandleList[2] = hThread3; /*All the above are of type HANDLE*/ Before closing the application, I want the thread to get its task done. So I want to make app wait till thread completes. So I do, WaitForMultipleObjects(3, HandleList, TRUE, INFINITE ); By this I'm able to make the thread, complete its task. But control never move to next line after the call to WaitForMultileObjects irrespective of all thread completing its task. If I use, some seconds instead of INFINITE, it comes to next line after that many secs, irrspective of whether thread completes its task or not. WaitForMultipleObjects(3, HandleList, TRUE, 10000 ); My problem here is, I'm can't go for seconds, as I may not be sure whether the threads will complete its task with the given time. To list my problem in simple words, I want all my thread to finish the task, before I close my app. How can I achieve it using WaitForMultipleObjects API?

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  • Using Threads to Handle Sockets

    - by user340468
    I am working on a java program that is essentially a chat room. This is an assignment for class so no code please, I am just having some issues determining the most feasible way to handle what I need to do. I have a server program already setup for a single client using threads to get the data input stream and a thread to handle sending on the data output stream. What I need to do now is create a new thread for each incoming request. My thought is to create a linked list to contain either the client sockets, or possibly the thread. Where I am stumbling is figuring out how to handle sending the messages out to all the clients. If I have a thread for each incoming message how can I then turn around and send that out to each client socket. I'm thinking that if I had a linkedlist of the clientsockets I could then traverse the list and send it out to each one, but then I would have to create a dataoutputstream each time. Could I create a linkedlist of dataoutputstreams? Sorry if it sounds like I'm rambling but I don't want to just start coding this, it could get messy without a good plan. Thanks!

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  • J2ME/Java: Referencing StringBuffer through Threads

    - by Jemuel Dalino
    This question might be long, but I want to provide much information. Overview: I'm creating a Stock Quotes Ticker app for Blackberry. But I'm having problems with my StringBuffer that contains an individual Stock information. Process: My app connects to our server via SocketConnection. The server sends out a formatted set of strings that contains the latest Stock trade. So whenever a new trade happens, the server will send out an individual Stock Quote of that trade. Through an InputStream I am able to read that information and place each character in a StringBuffer that is referenced by Threads. By parsing based on char3 I am able to determine a set of stock quote/information. char1 - to separate data char3 - means end of a stock quote/information sample stock quote format sent out by our server: stock_quote_name(char 1)some_data(char1)some_data(char1)(char3) My app then parses that stock quote to compare certain data and formats it how it will look like when displayed in the screen. When trades happen gradually(slow) the app works perfectly. However.. Problem: When trades happen too quickly and almost at the same time, My app is not able to handle the information sent efficiently. The StringBuffer has its contents combined with the next trade. Meaning Two stock information in one StringBuffer. field should be: Stock_quote_name some_data some_data sample of what's happening: Stock_quote_name some_data some_dataStock_quote_name some_data some_data here's my code for this part: while (-1 != (data = is.read())) { sb.append((char)data); while(3 != (data = is.read())) { sb.append((char)data); } UiApplication.getUiApplication().invokeLater(new Runnable() { public void run() { try { synchronized(UiApplication.getEventLock()) { SetStringBuffer(sb); DisplayStringBuffer(); RefreshStringBuffer(); } } catch (Exception e) { System.out.println("Error in setting stringbuffer: " + e.toString()); } } }); } public synchronized void DisplayStringBuffer() { try { //parse sb - string buffer ...... } catch(Exception ex) { System.out.println("error in DisplayStringBuffer(): " + ex.toString()); } } public synchronized void SetStringBuffer(StringBuffer dataBuffer) { this.sb =dataBuffer; System.out.println(sb); } public synchronized void RefreshStringBuffer() { this.sb.delete(0, this.sb.length()); } From what I can see, when trades happen very fast, The StringBuffer is not refreshed immediately and still has the contents of the previous trade, when i try to put new data. My Question is: Do you guys have any suggestion on how i can put data into the StringBuffer, without the next information being appended to the first content

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  • C# threads - Posting messages between threads

    - by Harsha
    Hi All, I am working on a project which involves reusing as well as migrating some of the existing MFC code to C#. The current code in MFC, creates some threads and uses ::PostthreadeMessage() and ON_THREAD_MESSAGE(msg,func) for inter thread asynchronous communication through messages. ::PostthreadeMessage() - sends a message to a particular thread id. ON_THREAD_MESSAGE(msg,func) - calls the function(func) when a message(msg) is received. Since i am not much aware of the threading interfaces in C#, i tried to search for similar API's in C#, but was not able to find any. It would be great, if somebody can help me in finding the appropriate functions for this purpose in C# Thanks, Harsha

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