threadpool

问题 In this web tutorial on threading in C#, Joseph Albahari writes: "Don't go sleeping in pooled threads!" Why should you not do this? How badly can it affect performance? (It's not that I want to do it; I'm just curious.) 回答1: Thread is a heavy-weight object. Creating a new thread requires lots of resources, such as assigning 1 MB for a managed stack, creating managed thread object, kernel stack, kernel thread object, user thread environment block. This all takes time and memory. Therefore you

问题 I set the max thread to 10. Then I added 22000 task using ThreadPool.QueueUserWorkItem. It is very likely that not all the 22000 task was completed after running the program. Is there a limitation how many task can be queued for avaiable threads? 回答1: The queue has no practical limit however the pool itself will not exceed 64 wait handles, ie total threads active. 回答2: If you need to wait for all of the tasks to process, you need to handle that yourself. The ThreadPool threads are all

问题 I've just started looking at Java's Executors class and the newCachedThreadPool( ) method. According to the API, the resulting thread pool reuses existing Thread objects for new tasks. I'm a bit puzzled how this is implemented because I couldn't find any method in the Thread API that lets you set the behaviour of an existing Thread object. For example, you can create a new Thread from a Runnable object, which makes the Thread call the Runnable 's run( ) method. However, there is no setter

问题 When does InvalidAsynchronousStateException get thrown? I have the following piece of code: control.InvokeRequired ? control.Invoke(expression) : expression(); In some random cases I get InvalidAsynchronousStateException and my application hangs, after doing some reading it seems to be that this exception will be thrown when the thread where the control was created finished. Is this correct? If so, this doesn't seem to be the case, unless something is making my application crash and this

问题 I would like to create a thread pool which will execute the most recently submitted task. Any advice on how to accomplish this? Thank you 回答1: You could probably just implement your own BlockingQueue wrapper that maps offer/poll to a stack. Then use this as the BlockingQueue implementation you pass to a ThreadPoolExecutor . My suggestion would be to wrap one of the existing Deque implementations such as ArrayDeque. This is not synchronized, so you'll need to wrap each of the BlockingQueue

问题 Are there any implementations of a thread pool (in Java) that ensures all tasks for the same logical ID are executed on the same thread? The logic I'm after is if there is already a task being executed on a specific thread for a given logical ID, then new tasks with the same ID are scheduled on the same thread. If there are no threads executing a task for the same ID then any thread can be used. This would allow tasks for unrelated IDs to be executed in parallel, but tasks for the same ID to

问题 Just right now I'm using following code to add queued threads. I don't like it. And my colleagues won't either because they don't know C# very well. All I want is of course to queue a method to be executed in a new thread. private static void doStuff(string parameter) { // does stuff } // call (a) ThreadPool.QueueUserWorkItem(a => doStuff("hello world")); // call (b) ThreadPool.QueueUserWorkItem(delegate { doStuff("hello world"); }); So are there other use variations of ThreadPool

问题 In C# is there any difference between using a delegate to do some work asynchronously (calling BeginInvoke()) and using a ThreadPool thread as shown below public void asynchronousWork(object num) { //asynchronous work to be done Console.WriteLine(num); } public void test() { Action<object> myCustomDelegate = this.asynchronousWork; int x = 7; //Using Delegate myCustomDelegate.BeginInvoke(7, null, null); //Using Threadpool ThreadPool.QueueUserWorkItem(new WaitCallback(asynchronousWork), 7);

问题 I have one query that is I have developed a code below of multiple threads named thread one and thread two, below is the code .. class multip implements Runnable { public void run() { for (int i = 0; i < 20; i++) { try { Thread.sleep(500); System.out.println(Thread.currentThread().getName()); System.out.println("i"); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } } public class MultiThread3 { public static void main(String... a) { multip obj =

问题 I am currently using CompletableFuture supplyAsync() method for submitting some tasks to common thread pool. Here is what code snippet looks like: final List<CompletableFuture<List<Test>>> completableFutures = resolvers.stream() .map(resolver -> supplyAsync(() -> task.doWork())) .collect(toList()); CompletableFuture.allOf(completableFutures.toArray(new CompletableFuture[completableFutures.size()])).join(); final List<Test> tests = new ArrayList<>(); completableFutures.stream() .map