Search Results

Search found 1638 results on 66 pages for 'multithreading'.

Page 59/66 | < Previous Page | 55 56 57 58 59 60 61 62 63 64 65 66  | Next Page >

• Perform tasks with delay, without delaying web response (ASP.NET)

  - by Tomas Lycken

  I'm working on a feature that needs to send two text messages with a 30 second delay, and it is crucial that both text messages are sent. Currently, this feature is built with ajax requests, that are sent with a 30 second javascript delay, but since this requires the user to have his browser open and left on the same page for at least 30 seconds, it is not a method I like. Instead, I have tried to solve this with threading. This is what I've done: Public Shared Sub Larma() Dim thread As New System.Threading.Thread(AddressOf Larma_Thread) thread.Start() End Sub Private Shared Sub Larma_Thread() StartaLarm() Thread.Sleep(1000 * 30) StoppaLarm() End Sub A web handler calls Larma(), and StartaLarm() and StoppaLarm() are the methods that send the first and second text messages respectively. However, I only get the first text message delivered - the second is never sent. Am I doing something wrong here? I have no deep understanding of how threading works in ASP.NET, so please let me know how to accomplish this.

  Read the article

• Thread toggling

  - by sid

  Hi all, In Ubuntu, I am running 2 'C' applications, When I press key up/down the applications are alternatively getting the events. What might be the problem/solution? Ex: I have 'A application' and 'B application', I launch 'A application' and press the key up/down its working fine. If I simultaneously launch 'B application' and focus is on 'B application' then pressing key up/down will toggle between 'A application' & 'B application' so 2 times I have to press the key to move on 'B application'(focus is on 'B application'). 'A application' and 'B application' are threads. Thanks in advance-opensid

  Read the article

• c# run process without freezing my App's GUI

  - by Data-Base

  Hello, I want to start a process (calling another program), currently the external program takes time (it is normal)! but it freezes my GUI I saw allot of examples and I'm learning, it is hard to figure it out, trying to read and learn threading, but it is not that easy (at least for me) and good simple tutorial or code sample? cheers

  Read the article

• How to insert into data base using multi threading programming [closed]

  - by user1196650

  I am having a method and that method needs to do the following thing: It has to insert records into a database. No insert is done for the same table again. All inserts are into different tables. I need a multi threading logic which inserts the details into db using different threads. I am using oracle db and driver configuration and remaining stuff are perfect. Please help me with an efficient answer. Can anyone could provide me with a skeleton logic of the program.

  Read the article

• linux process scheduling delayed for long time

  - by Medicine

  I have done strace on my multi-threaded c++ application running on linux after couple hours of running, none of the threads got run, for about 12 seconds. I have seen that the unfinished select system call which is called with a timeout was unfinished before the thread was suspended, reported after it resumed that, it took 11.x seconds for the operation to finish. This is clear indication that the process got starved for a long time. All threads in the process are created with default scheduling policy(SCHED_OTHER) of linux and default priority. There are another 5 similar apps running on the same box which are also heavy I/O bound like this app due to heavy data received on the socket. But most of the time, this app is getting scheduled delay. The other apps are created with same sched policy and priority as this i.e. the defaults. why is only this process gets blocked almost all of the time? Could it be because this process is more I/O intensive as in more busy due to may be higher rates of data? So, the linux dynamic priority adjusting in play here which pushed this process down?

  Read the article

• The cross-thread usage of "HttpContext.Current" property and related things

  - by smwikipedia

  I read from < Essential ASP.NET with Examples in C# the following statement: Another useful property to know about is the static Current property of the HttpContext class. This property always points to the current instance of the HttpContext class for the request being serviced. This can be convenient if you are writing helper classes that will be used from pages or other pipeline classes and may need to access the context for whatever reason. By using the static Current property to retrieve the context, you can avoid passing a reference to it to helper classes. For example, the class shown in Listing 4-1 uses the Current property of the context to access the QueryString and print something to the current response buffer. Note that for this static property to be correctly initialized, the caller must be executing on the original request thread, so if you have spawned additional threads to perform work during a request, you must take care to provide access to the context class yourself. I am wondering about the root cause of the bold part, and one thing leads to another, here is my thoughts: We know that a process can have multiple threads. Each of these threads have their own stacks, respectively. These threads also have access to a shared memory area, the heap. The stack then, as I understand it, is kind of where all the context for that thread is stored. For a thread to access something in the heap it must use a pointer, and the pointer is stored on its stack. So when we make some cross-thread calls, we must make sure that all the necessary context info is passed from the caller thread's stack to the callee thread's stack. But I am not quite sure if I made any mistake. Any comments will be deeply appreciated. Thanks. ADD Here the stack is limited to user stack.

  Read the article

• Timer C#. Start, stop, and get the amount of time between the calls

  - by user1886060

  I'm writing UDP chat with reliable data transfer. I need to start a timer when a packet is sent, and stop it as soon it receives an answer from the server(ACK- acknowledgment). Here is my code: private void sendButton_Click(object sender, EventArgs e) { Packet snd = new Packet(ack, textBox1.Text.Trim()); textBox1.Text = string.Empty; Smsg = snd.GetDataStream();//convert message into array of bytes to send. while (true) { try { // Here I need to Start a timer! clientSock.SendTo(Smsg, servEP); clientSock.ReceiveFrom(Rmsg, ref servEP); //Here I need to stop a timer and get elapsed amount of time. Packet rcv = new Packet(Rmsg); if (Rmsg != null && rcv.ACK01 != ack) continue; if (Rmsg != null && rcv.ACK01 == ack) { this.displayMessageDelegate("ack is received :"+ack); ChangeAck(ack); break; } Thank you.

  Read the article

• Java synchronizing static list ?

  - by JavaUser

  Hi, In a Java class , i am having a static list so this list is shared across all the objects of this class.The business logic in this class will run periodically which is invoked by some method with out passing instance parameters.Now I want to invoke this run method based on the list(I will add some vales into this list based on JMS) ,this list may empty sometimes and after finishing the run , i am emptying this list.Now my question is , whether I need to synchronize this list or not? Also let me know is there any other way to pass value in one object instance(Thread1) to other object instance (Thread2) other than having Static variable(static list)? Thx

  Read the article

• Running 2 threads simultaneously

  - by lamsaitat

  In the case of an IM client. I have made 2 separate threads to handle sending packets (by std io) and receiving packets. The question is how to make these 2 threads run simultaneously so that I can keep prompting for input while at the same time be ready to receive packets at any time? I have already tried setting a timer but the data is always lost receiving.

  Read the article

• Not Able to call The method Asynchronously Unit Test.

  - by user43838

  Hi everyone, I am trying to call a method that passes an object called parameters. Thread t1 = new Thread(delegate() { target.DoWork(parameters); }); t1.Start(); My test is failing all the time and i am not able step through the method.. Can someone please put me in the right direction Thanks

  Read the article

• Java concurrency - Should block or yield?

  - by teto

  Hi, I have multiple threads each one with its own private concurrent queue and all they do is run an infinite loop retrieving messages from it. It could happen that one of the queues doesn't receive messages for a period of time (maybe a couple seconds), and also they could come in big bursts and fast processing is necessary. I would like to know what would be the most appropriate to do in the first case: use a blocking queue and block the thread until I have more input or do a Thread.yield()? I want to have as much CPU resources available as possible at a given time, as the number of concurrent threads may increase with time, but also I don't want the message processing to fall behind, as there is no guarantee of when the thread will be reescheduled for execution when doing a yield(). I know that hardware, operating system and other factors play an important role here, but setting that aside and looking at it from a Java (JVM?) point of view, what would be the most optimal?

  Read the article

• ThreadQueue problems in "Accelerated C# 2008"

  - by Singlet

  Example for threading queue book "Accelerated C# 2008" (CrudeThreadPool class) not work correctly. If I insert long job in WorkFunction() on 2-processor machine executing for next task don't run before first is over. How to solve this problem? I want to load the processor to 100 percent public class CrudeThreadPool { static readonly int MAX_WORK_THREADS = 4; static readonly int WAIT_TIMEOUT = 2000; public delegate void WorkDelegate(); public CrudeThreadPool() { stop = 0; workLock = new Object(); workQueue = new Queue(); threads = new Thread[ MAX_WORK_THREADS ]; for( int i = 0; i < MAX_WORK_THREADS; ++i ) { threads[i] = new Thread( new ThreadStart(this.ThreadFunc) ); threads[i].Start(); } } private void ThreadFunc() { lock( workLock ) { int shouldStop = 0; do { shouldStop = Interlocked.Exchange( ref stop, stop ); if( shouldStop == 0 ) { WorkDelegate workItem = null; if( Monitor.Wait(workLock, WAIT_TIMEOUT) ) { // Process the item on the front of the queue lock( workQueue ) { workItem =(WorkDelegate) workQueue.Dequeue(); } workItem(); } } } while( shouldStop == 0 ); } } public void SubmitWorkItem( WorkDelegate item ) { lock( workLock ) { lock( workQueue ) { workQueue.Enqueue( item ); } Monitor.Pulse( workLock ); } } public void Shutdown() { Interlocked.Exchange( ref stop, 1 ); } private Queue workQueue; private Object workLock; private Thread[] threads; private int stop; } public class EntryPoint { static void WorkFunction() { Console.WriteLine( "WorkFunction() called on Thread {0}",Thread.CurrentThread.GetHashCode() ); //some long job double s = 0; for (int i = 0; i < 100000000; i++) s += Math.Sin(i); } static void Main() { CrudeThreadPool pool = new CrudeThreadPool(); for( int i = 0; i < 10; ++i ) { pool.SubmitWorkItem( new CrudeThreadPool.WorkDelegate( EntryPoint.WorkFunction) ); } pool.Shutdown(); } }

  Read the article

• How do I make child thread exit when main thread exit?

  - by httpinterpret

  void forloop2() { int i = 0; while(TRUE) { printf("forloop2\n"); } } int main() { GThread *Thread1; GtkWidget *window; g_thread_init(NULL); gdk_threads_init(); gdk_threads_enter (); Thread1 = g_thread_create((GThreadFunc)forloop2, NULL, TRUE, NULL); gtk_init(NULL, NULL); window = gtk_window_new(GTK_WINDOW_TOPLEVEL); gtk_widget_show_all (window); gtk_main(); g_thread_join(Thread1); gdk_threads_leave (); } When I close the window, how to make Thread1 also exit?

  Read the article

• Execute PHP file in background

  - by Spyric

  I have some php code, that execute for a very long time. I need to realise next scheme: User enter on some page(page 1) This page starts execution of my large PHP script in background .(Every change is writting to database) We sent every N seconds query to database to get current status of execution. I don't want to use exec command because 1000 users makes 1000 php processes. It's not way for me...

  Read the article

• OpenGL multiple threads, variable handling [closed]

  - by toeplitz

  I have written an OpenGL program which runs in the following way: Main: - Initialize SDL - Create thread which has the OpenGL context: - Renderloop - Set camera (view) matrix with glUniform. - glDrawElements() .... etc. - Swapbuffers(); - Main SDL loop handling input events and such. - Update camera matrix of type glm::mat4. This is how I pass my camera object to the class that handles opengl. Camera *cam = new Camera(); gl.setCam(cam); where void setCam(Camera *camera) { this->camera = camera; } For rendering in the opengl context thread, this happens: glm::mat4 modelView = camera->view * model; glUniformMatrix4fv(shader->bindUniform("modelView"), 1, GL_FALSE, glm::value_ptr(modelView)); In the main program where my SDL and other things are handles I then recompute the view matrix. This his working fine without me using any mutex locks. Is this correct? On the other hand, I add objects to my scene by an "upload queue" and in this case I have to mutex lock my upload queue vector (vector class type) when adding items to it or else the program crashes. In summary: I recompute my matrix in a different thread and then use it in the opengl thread without any mutex lock. Why is this working? Edit: I think my question is similar to what was asked here: Should I lock a variable in one thread if I only need it's value in other threads, and why does it work if I don't?, only in my case it is even more simple with only one matrix being changed.

  Read the article

• [java] run 2 threads simultaneously

  - by lamsaitat

  hi all, in the case of an IM client. i have made 2 separate threads to handle sending packets (by std io) and receiving packets. the question is how to make these 2 threads run simultaneously so that i can keep prompting for input while at the same time be ready to receive packets at any time? i have already tried setting a timer but the data is always lost receiving.

  Read the article

• Please suggest good book/website to for Threads and Concurrency?

  - by learner

  I have gone through Head First Java and some other sites but I couldn't find complete stuff related to Threads and additional concurrency packages at one place. Please suggest a book/website which covers complete Threads with more details like Synchronize and locking of objects More detailed about volatile Visibility issues in Threads java.util.concurrent package java.util.concurrent.atomic package

  Read the article

• makecontext segfault?

  - by cdietschrun

  I am working on a homework assignment that will be due in the next semester. It requires us to implement our own context switching/thread library using the ucontext API. The professor provides code that does it, but before a thread returns, he manually does some work and calls an ISR that finds another thread to use and swapcontexts to it or if none are left, exits. The point of the assignment is to use the uc_link field of the context so that when it hits a return it takes care of the work. I've created a function (type void/void args) that just does the work the functions did before (clean up and then calls ISR). The professor said he wanted this. So all that's left is to do a makecontext somewhere along the way on the context in the uc_link field so that it runs my thread, right? Well, when I do makecontext on seemingly any combination of ucontext_t's and function, I get a segfault and gdb provides no help.. I can skip the makecontext and my program exist 'normally' when it hits a return in the threads I created because (presumably) the uc_link field is not properly setup (which is what I'm trying to do). I also can't find anything on why makecontext would segfault. Can anyone help? stack2.ss_sp = (void *)(malloc(STACKSIZE)); if(stack2.ss_sp == NULL){ printf("thread failed to get stack space\n"); exit(8); } stack2.ss_size = STACKSIZE; stack2.ss_flags = 0; if(getcontext(&main_context) == -1){ perror("getcontext in t_init, rtn_env"); exit(5); } //main_context.uc_stack = t_state[i].mystk; main_context.uc_stack = stack2; main_context.uc_link = 0; makecontext(&main_context, (void (*)(void))thread_rtn, 0); I've also tried just thread_rtn, &thread_rtn and other things. thread_rtn is declared as void thread_rtn(void). later, in each thread. run_env is of type ucontext_t: ... t_state[i].run_env.uc_link = &main_context;

  Read the article

• Real World Examples of read-write in concurrent software

  - by Richard Fabian

  I'm looking for real world examples of needing read and write access to the same value in concurrent systems. In my opinion, many semaphores or locks are present because there's no known alternative (to the implementer,) but do you know of any patterns where mutexes seem to be a requirement? In a way I'm asking for candidates for the standard set of HARD problems for concurrent software in the real world.

  Read the article

• How to tell if there is an available thread in a thread pool in java

  - by Gormcito

  I am trying to proccess a queue of tasks from a database table as fast as possible while also limiting the number of threads to process the tasks. I am using a fixed sized thread pool with Executors.newFixedThreadPool(N); I want to know if there is a way of knowing if the thread pool is full, by that I mean are there currently 50 threads running, if so then I'll wait for a thread to be available before starting a new one instead of sleeping the main thread. Code of what I would like to do: ExecutorService executor = Executors.newFixedThreadPool(N); ResultSet results; while( true ) { results = getWaitingTasksStmt.executeQuery(); while( results.next() && executor.notFull() ) { executor.submit( new thread( new runnableInheritedClass(results) ) ); } }

  Read the article

• Have main thread wait for a boost thread complete a task (but not finish).

  - by JAKE6459

  I have found plenty on making one thread wait for another to finish executing before continuing, but that is not what I wanted to do. I am not very familiar with using any multi-threading apis but right now I'm trying to learn boost. My situation is that I am using my main thread (the starting one from int main()) to create an instance of a class that is in charge of interacting with the main GUI. A class function is then called that creates a boost thread which in turn creates the GUI and runs the message pump. The thing I want to do is when my main thread calls the classes member function to create the GUI, I don't want that function to return until I tell it to from the newly created thread. This way my main thread can't continue and call more functions from the GUI class that interact with the GUI thread until that thread has completed GUI creation and entered the message loop. I think I may be able to figure it out if it was multiple boost thread objects interacting with each other, but when it is the main thread (non-boost object) interacting with a boost thread object, I get lost. Eventually I want a loop in my main thread to call a class function (among other tasks) to check if the user as entered any new input into the GUI (buy any changes detected by the message loop being updated into a struct and changing a bool to tell the main thread in the class function a change has occurred). Any suggestions for any of this would be greatly appreciated. This is the member function called by the main thread. int ANNGUI::CreateGUI() { GUIMain = new Main(); GUIThread = new boost::thread(boost::bind(&Main::MainThreadFunc, GUIMain)); return 0; }; This is the boost thread starting function. void Main::MainThreadFunc() { ANNVariables = new GUIVariables; WndProc = new WindowProcedure; ANNWindowsClass = new WindowsClass(ANNVariables, WndProc); ANNWindow = new MainWindow(ANNVariables); GUIMessagePump = new MessagePump; ANNWindow-ShowWindows(); while(true) { GUIMessagePump-ProcessMessage(); } }; BTW, everything compiles fine and when I run it, it works I just put a sleep() in the main thread so I can play with the GUI a little.

  Read the article

• Thread-safe get (accessor method)

  - by sonofdelphi

  I'm currently using the following code for thread-safe access of a variable. int gnVariable; void getVariableValue(int *pnValue) { acquireLock(); //Acquires the protection mechanism *pnValue = gnVariable; releaseLock(); //Releasing the protection mechanism } I would like to change my API signature to a more user-friendly int getVariableValue(void); How should I rewrite the function - such that the users of the API don't have to bother about the locking/unlocking details?

  Read the article

• Queues And Wait Handles in C#

  - by Michael Covelli

  I've had the following code in my application for some years and have never seen an issue from it. while ((PendingOrders.Count > 0) || (WaitHandle.WaitAny(CommandEventArr) != 1)) { lock (PendingOrders) { if (PendingOrders.Count > 0) { fbo = PendingOrders.Dequeue(); } else { fbo = null; } } // Do Some Work if fbo is != null } Where CommandEventArr is made up of the NewOrderEvent (an auto reset event) and the ExitEvent (a manual reset event). But I just realized today that its not thread safe at all. If this thread gets interrupted right after the first (PendingOrder.Count 0) check has returned false. And then the other thread both enqueues an order and sets the NewOrderEvent before I get a chance to wait on it, the body of the while loop will never run. What's the usual pattern used with a Queue and an AutoResetEvent to fix this and do what I'm trying to do with the code above?

  Read the article

• Help with java threads or executors: Executing several MySQL selects, inserts and updates simmultane

  - by Martin

  Hi. I'm writing an application to analyse a MySQL database, and I need to execute several DMLs simmultaneously; for example: // In ResultSet rsA: Select * from A; rsA.beforeFirst(); while (rsA.next()) { id = rsA.getInt("id"); // Retrieve data from table B: Select * from B where B.Id=" + id; // Crunch some numbers using the data from B // Close resultset B } I'm declaring an array of data objects, each with its own Connection to the database, which in turn calls several methods for the data analysis. The problem is all threads use the same connection, thus all tasks throw exceptios: "Lock wait timeout exceeded; try restarting transaction" I believe there is a way to write the code in such a way that any given object has its own connection and executes the required tasks independent from any other object. For example: DataObject dataObject[0] = new DataObject(id[0]); DataObject dataObject[1] = new DataObject(id[1]); DataObject dataObject[2] = new DataObject(id[2]); ... DataObject dataObject[N] = new DataObject(id[N]); // The 'DataObject' class has its own connection to the database, // so each instance of the object should use its own connection. // It also has a "run" method, which contains all the tasks required. Executor ex = Executors.newFixedThreadPool(10); for(i=0;i<=N;i++) { ex.execute(dataObject[i]); } // Here where the problem is: Each instance creates a new connection, // but every DML from any of the objects is cluttered in just one connection // (in MySQL command line, "SHOW PROCESSLIST;" throws every connection, and all but // one are idle). Can you point me in the right direction? Thanks

  Read the article

• C# 4.0 how to pass variables to threads?

  - by Aviatrix

  How would i pass some parameters to a new thread that runs a function from another class ? What i'm trying to do is to pass an array or multiple variables to a function that sits in another class and its called by a new thread. i have tried to do it like this Functions functions = new Functions(); string[] data; Thread th = new Thread(new ParameterizedThreadStart(functions.Post())); th.Start(data); but it shows error "No overload for method 'Post' takes 0 arguments" Any ideas ?

  Read the article

< Previous Page | 55 56 57 58 59 60 61 62 63 64 65 66  | Next Page >