Messages in this thread |  | | Date | Mon, 13 Jun 2022 09:54:37 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH v4] sched/fair: Introduce SIS_UTIL to search idle CPU based on sum of util_avg |
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On Mon, Jun 13, 2022 at 04:06:36PM +0800, Chen Yu wrote: > On Mon, Jun 13, 2022 at 03:40:52PM +0800, Yicong Yang wrote: > > On 2022/6/13 0:34, Chen Yu wrote: > > > > [cut...] > > > #define NUMA_IMBALANCE_MIN 2 > > > diff --git a/kernel/sched/features.h b/kernel/sched/features.h > > > index 1cf435bbcd9c..3334a1b93fc6 100644 > > > --- a/kernel/sched/features.h > > > +++ b/kernel/sched/features.h > > > @@ -61,6 +61,7 @@ SCHED_FEAT(TTWU_QUEUE, true) > > > * When doing wakeups, attempt to limit superfluous scans of the LLC domain. > > > */ > > > SCHED_FEAT(SIS_PROP, true) > > > +SCHED_FEAT(SIS_UTIL, true) > > > > > > > confused here that shouldn't we have SCHED_FEAT(SIS_PROP, false)? With SIS_UTIL enabled, SIS_PROP will have no > > effect since nr is overridden by SIS_UTIL. > Yes, no matter what SIS_PROP is set, the result of SIS_UTIL would be used to decide > the scan depth. We don't change the default value of SIS_PROP here, as this patch > tends to only touch one feature at one time. And the options could be tuned by user via > sysfs manually. Besides, the target is to replace SIS_PROP with another search policy, > Peter mentioned that "And ideally we're remove SIS_PROP after a few releases if this > works out", so I assume that changing the default value of SIS_PROP does not matter > in current patch. >
I had expected it to be disabled given that SIS_PROP does work to calculcate nr, then discards it, and uses SIS_UTIL. If SIS_UTIL shows a regression and reports a bug, the first step would be to disable SIS_UTIL and enable SIS_PROP via sched_feat.
-- Mel Gorman SUSE Labs
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