SetMaxThreads Method

ThreadPool.SetMaxThreads Method (Int32, Int32)


Sets the number of requests to the thread pool that can be active concurrently. All requests above that number remain queued until thread pool threads become available.

Namespace:   System.Threading
Assembly:  mscorlib (in mscorlib.dll)

[SecurityPermissionAttribute(SecurityAction.Demand, ControlThread = true)]
public static bool SetMaxThreads(
	int workerThreads,
	int completionPortThreads


Type: System.Int32

The maximum number of worker threads in the thread pool.

Type: System.Int32

The maximum number of asynchronous I/O threads in the thread pool.

Return Value

Type: System.Boolean

true if the change is successful; otherwise, false.

You cannot set the number of worker threads or the number of I/O completion threads to a number smaller than the number of processors in the computer.

If the common language runtime is hosted, for example by Internet Information Services (IIS) or SQL Server, the host can limit or prevent changes to the thread pool size.

Use caution when changing the maximum number of threads in the thread pool. While your code might benefit, the changes might have an adverse effect on code libraries you use.

Setting the thread pool size too large can cause performance problems. If too many threads are executing at the same time, the task switching overhead becomes a significant factor.


for the ability to control threads. Permission value: SecurityPermissionFlag.ControlThread

.NET Framework
Available since 2.0
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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