CODEWITHSUNDEEP
c#multithreadingcpu
Masoud
Masoud

Reputation: 1405

Specify a special cpu for a thread in C#

I have 2 threads. I want to tell one of them to run on first cpu and the second one on the second cpu for example in a machine with two cpu. how can I do that?

this is my code

UCI UCIMain = new UCI();
Thread UCIThread = new Thread(new ThreadStart(UCIMain.main));
UCIThread.Priority = ThreadPriority.BelowNormal;
UCIThread.Start();

and for sure the class UCI has a member function named main. I want to set this thread in 1st processor for example

Upvotes: 3

Views: 1033

Answers (3)

Tudor
Tudor

Reputation: 62479

I wouldn't recommend this, but if you really need to: it is possible by tapping into the native Win32 system calls, specifically SetThreadAffinityMask. You will need to do some DllImports:

[DllImport("kernel32.dll")]
static extern IntPtr GetCurrentThread();
[DllImport("kernel32.dll")]
static extern IntPtr SetThreadAffinityMask(IntPtr hThread, IntPtr dwThreadAffinityMask);

And then use the them inside each spawned thread (with a different parameter for the mask, of course):

// set affinity of current thread to the given cpuID
SetThreadAffinityMask(GetCurrentThread(), new IntPtr(1)); // CPU 0

Upvotes: 5

oleksii
oleksii

Reputation: 35935

Don't do this. OS task scheduler is much more clever than manual tweaks. You can technically use thread affinity, but it's not usually a good idea. Instead use thread pool or TPL library.

If one core is super busy and another one is not. Then one thread will be starving for processing power, whereas another core will not be loaded at all.

Upvotes: 2

jere
jere

Reputation: 4304

On .NET, you have ProcessThread.ProcessorAffinity and ProcessThread.IdealProcessor

But since you are talking about a Thread and not Process, I believe there is no directly available way of doing this in .NET.

There is Thread.SetProcessorAffinity() but it's only available for XNA on Xbox.

Upvotes: 2

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