Active Thread Number in Thread Pool

Question

When I write the below code, why do I get avaliable Thread number like 1022, 1020. I have to get 25 thread max as I am using thread pool.

I guess the ouput thread n

Answer 1

I set both to 10001, using ThreadPool.SetMaxThread. After that whenever, I run your program it shows max thread 10001, its persisted. I didn't restarted my core i 5 system.

After that I set both it to 10000000 , and it is showing following thread max count

worker:32767 ioCompletion:32767

So on my Windows 7 Intel Core i5 , this is the maximum capacity.

Answer 2

int available;
int maxLimit;
System.Threading.ThreadPool.GetAvailableThreads(out available, out maxLimit);

Answer 3

Use ThreadPool.GetMaxThreads to get what you want.

This article helps explain everything you need to know about ThreadPool.

Answer 4

I have to get 25 thread max as I am using thread pool.

The maximum number of threads in the thread-pool per core has changed a lot over time. It's no longer 25 per core, which I suspect is what you were expecting.

For example, running this on my quad-core hyperthreaded laptop with .NET 4, I get a maximum of 32767 worker threads and 1000 IO completion port threads:

using System;
using System.Threading;

class Test
{
    static void Main()
    {
        int worker; 
        int ioCompletion;
        ThreadPool.GetMaxThreads(out worker, out ioCompletion);
        Console.WriteLine("{0} / {1}", worker, ioCompletion);
    }    
}

Under .NET 3.5 I get 2000 worker threads and still 1000 IO completion port threads.

That isn't the number of threads actually in the thread pool though - it's the maximum number that the thread pool allows itself to create over time.