Is there any way to set processor affinity of a powershell script before execution?

Question

There are lots of examples showing the use of Get-Process myprocess to change the processor affinity, and some examples using Get-WMIObject; but these won't work for my use. I want to set processor affinity of my script as it executes. Is there a way to declare processor affinity when calling powershell.exe, or from within the script itself?

The exe I'm calling is in cygwin; which appears to change the affinity after being started with cmd.exe /c start <command> /affinity 16

Answer 1

This seems to work for me, but I haven't tested it. It seems to update what Task Manager sees, however.

$thisProcess = [System.Diagnostics.Process]::GetCurrentProcess();
$thisProcess.ProcessorAffinity = 0x1;

ProcessorAffinity is a bitmask, so 0x1 is core 1, 0x2 is core 2, 0x4 is core 3, 0x8 is core 4, and so on. If you want to set cores 1-4, it's 0xF, cores 1-9, 0x1FF, etc. I don't think there's any magic value to set it back to "All".

You could also use Get-Process -Id $pid, since $pid is an automatic variable with the current process' PID.