Messages in this thread | | | Date | Mon, 13 Jun 2022 17:08:26 +0800 | From | Chen Yu <> | 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 09:54:37AM +0100, Mel Gorman wrote: > 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, I see, disable SIS_PROP would reduce duplicated nr calculation. > 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. OK, I'll change it in next version.
thanks, Chenyu > > -- > Mel Gorman > SUSE Labs
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