Change numa group in running process via PowerShell

Question

I would like to change numa group in running process via PS

all the time is take group 1 :( and cpu work 50%

this - I can do by hand but I don`t know how via PS

my problem is that I have processes that always get assigned to the same group, resulting in 50% of the cpu

Mathias when I add 2 I get this (in the powershell instruction the bitmask controlls number of cpus to in a processor group only - so if the process get's assigned to a group 0, the instruction only changes the number of cpus in this group)

score 2 · Answer 1 · answered Nov 02 '20 at 11:12

2

You need to set the ProcessorAffinity property on the corresponding process:

Get-Process vmmem |ForEach-Object {
  $_.ProcessorAffinity = [IntPtr]::new([long]-1) # -1 corresponds to all 64 bits set
}

answered Nov 02 '20 at 11:12

Mathias R. Jessen

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it work only in one group, we have 72 cores (two processors) – Rafał Developer Nov 02 '20 at 11:15
(36 cores / 72 vcpus) (2 numa nodes) – Rafał Developer Nov 02 '20 at 11:21
@RafałDeveloper so when you set the `ProcessorAffinity` like in my example above, task manager still only shows half of the CPU's checked? Try setting it to `2` instead of `-1` (I can't remember if it affects groups as a whole and I don't have a NUMA die to test) – Mathias R. Jessen Nov 02 '20 at 11:25
all cpus (exactly 35) checked in group 1 and zero cpus in group 0 – Rafał Developer Nov 02 '20 at 11:31
Alright, that means each bit controls a group, so setting it to `3` should allow execution on both groups – Mathias R. Jessen Nov 02 '20 at 11:33
@RafałDeveloper Well, you're in a better position to validate the right pattern than I am, so I would suggest trying different values until you get the right result (sorry I can't be of more help) – Mathias R. Jessen Nov 02 '20 at 11:36
in the powershell instruction the bitmask controlls number of cpus to in a processor group only - so if the process get's assigned to a group 0, the instruction only changes the number of cpus in this group. – Rafał Developer Nov 02 '20 at 11:40

score 2 · Accepted Answer · answered Nov 10 '20 at 17:10

This is not what I call an answer actually (I am not a C++ dev), however, here is a part of the way to probably achieve this :

$MethodDefinition = @'
    [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
    public static extern bool SetThreadGroupAffinity(......);
'@
$Kernel32 = Add-Type -MemberDefinition $MethodDefinition -Name "Kernel32" -PassThru

#Retrieve the Thread handle first
#Call by $Kernel32::SetThreadGroupAffinity(......)

MS docs SetThreadGroupAffinity, MS docs GoupAfffinity Structure

May be this one be useful too MS docs SetThreadAffinityMask

Change numa group in running process via PowerShell

2 Answers2