委托和初次调用的延迟

Question

There is delay in the BeginInvoke and actual invoke of the method.

In my code I call method using delegate.BeginInvoke in the for loop and after for loop there is code to wait for all thread to complete.

for(count=0;count<4; Count;count++)
{
    MethodDelegatedglt;
    dglt = new MethodDelegate(this.ProcessResponse);

    asyncResult = dglt.BeginInvoke(Param1, null, null);
    wHandle.Add(asyncResult.AsyncWaitHandle);
}

logMessage( GUIDSessionXML + " Waiting on all threads to complete.", LogLevel.Debug);

As you can see in above code delegate is define on line 1 and on line 2 it is assigned. On line 3 asynchronous call is made and added in waithandle array.

Below I am waiting for the all wait handle to complete

if (!System.Threading.WaitHandle.WaitAll(wHandle, connectionTimeOut, false) )
{
   ...      
}

from the log I came to know that method is not called as soon as we call BeginInvoke , there is delay.

2014-06-20 15:19:42.6104 => Waiting on all threads to complete.
2014-06-20 15:19:44.4044 => Start of ProcessResponse.

as you can see above methods is called after nearly 2 sec.

What could be the reason behind this and how it can be fixed, any help on this would be appreciated.

Answer 1

Thread pool can be lazy when creating new threads. A new thread creation can be delayed for up to 500ms (for more details, check Joe Duffy's "CLR thread pool injection, stuttering problems" ).

To account for this behavior, increase the number of pre-allocated threads with ThreadPool.SetMinThreads .

Most likely, you should re-evaluate the design of your application and consider using some modern technologies of parallel programming: Task Parallel Library (TPL) (including Dataflow ), async/await , Reactive Extensions (Rx) .