Re: [PATCH v4 6/7] sched/fair: skip busy cores in SIS search

From: Abel Wu
Date: Wed Jun 22 2022 - 00:04:19 EST



On 6/22/22 2:14 AM, Chen Yu Wrote:
Hi Abel,
On Sun, Jun 19, 2022 at 08:04:50PM +0800, Abel Wu wrote:
Try to improve efficiency of SIS domain search by filtering out busy
cores, and as a result the more overloaded the system is, the less
cpus will be scanned.

The filter is supposed to contain unoccupied cpus of the LLC. And we
propagate these cpus to the filter one at a time at core granule.
This can help spreading load to different cores given that the search
depth is limited. The chosen cpu to be propagated is guaranteed to be
unoccupied at that time.

When idle cpu exists, the last one is preferred in order not to
conflict with periodic load balancing during which the first idle
cpu (if any) is chosen to be fed with tasks.

Maybe the content in cover letter could be copied into this git log for
future reference?

Definitely. Will fix this in next version.
Thanks.