Question

I have developed a .net application using .net framework 4.0 where I have used parallel.for() loop for multi threading. I have used the following configuration:

1. Windows 7
2. IIS 7.0
3. Framework v4.0.30319

I have used ParallelOptions() class and the “MaxDegreeOfParallelism” property of this class is set to 5. I have logged the “Thread.CurrentThread.ManagedThreadId” in a log file to check whether 5 threads were created at the runtime. I have tested this application in two different environments. When the application is running at the environment where it has been developed it’s creating 5 thread IDs. But while it’s running at the other environment it’s creating 6 or 7 threads IDs. The application is compiled at the 1st environment only. I have used the published version of the application to test at the 2nd environment.
Can anyone help me by informing why this is happening and how to resolve it?

Answer 1

Parallel.For uses thread pool threads. The MaxDegreeOfParallelism controls the maximum concurrent number of threads being used, not 5 particular threads – the thread pool is at liberty to process work on any of its threads, and Parallel.For makes sure only 5 are running at the same time.