Re: [HTCondor-users] Future improvements to NUMA affinity algorithms

[Greg Thain <gthain@xxxxxxxxxxx>]

On 7/30/25 4:51 PM, Jaime Frey via HTCondor-users wrote:
> My suspicion is that this wonât have much effect on the difference in CPU scheduling efficiency between ASSIGN_CPU_AFFINITY and cgroups for enforcing CPU usage limitations.
> HTCondor will still ignore NUMA locality when selecting which cores to assign to a job.
> And ASSIGN_CPU_AFFINITY doesnât allow a job to use additional cores when theyâre idle (if job has more processes/threads than assigned cores).


My hope is that algorithms like this will allow HTCondor and really any 
job manager to work better on NUMA machines without the admin having to 
set ASSIGN_CPU_AFFINITY. The kernel is always going to have a better 
idea about the memory topology of any given system than HTCondor does. 
So, in a perfect world, we leave core-scheduling to the kernel, and my 
reading of this change is that it helps the kernel schedule a bit better 
without devolving to forcing processor affinity to a job.


-greg