To set the affinity of CPUs using C#

Question

I have created a window application in C#.Now I want to set the CPU affinity for this application.I may have 2 processors,4 processors,8 processors or may be more than 8 processors.

I want to set the cpu affinity using input from interface.

How can i achieve this? How can it is possible to set the affinity using Environment.ProcessorCount?

Answer 1

Try this:

Process.GetCurrentProcess().ProcessorAffinity = (System.IntPtr)2;

Here's more about it.

ProcessorAffinity represents each processor as a bit. Bit 0 represents processor one, bit 1 represents processor two, and so on. The following table shows a subset of the possible ProcessorAffinity for a four-processor system.

Property value (in hexadecimal)  Valid processors

0x0001                           1
0x0002                           2
0x0003                           1 or 2
0x0004                           3
0x0005                           1 or 3
0x0007                           1, 2, or 3
0x000F                           1, 2, 3, or 4

Here's a small sample program:

//TODO: manage exceptions
class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine("Total # of processors: {0}", Environment.ProcessorCount);
        Console.WriteLine("Current processor affinity: {0}", Process.GetCurrentProcess().ProcessorAffinity);
        Console.WriteLine("*********************************");
        Console.WriteLine("Insert your selected processors, separated by comma (first CPU index is 1):");
        var input = Console.ReadLine();
        Console.WriteLine("*********************************");
        var usedProcessors = input.Split(',');

        //TODO: validate input
        int newAffinity = 0;
        foreach (var item in usedProcessors)
        {
            newAffinity = newAffinity | int.Parse(item);
            Console.WriteLine("Processor #{0} was selected for affinity.", item);
        }
        Process.GetCurrentProcess().ProcessorAffinity = (System.IntPtr)newAffinity;
        Console.WriteLine("*********************************");
        Console.WriteLine("Current processor affinity is {0}", Process.GetCurrentProcess().ProcessorAffinity);
    }
}