Messages in this thread | | | Date | Wed, 22 Jan 2020 13:55:09 +0000 | From | Mel Gorman <> | Subject | Re: [PATCH v2] sched/fair: Optimize select_idle_core |
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On Fri, Dec 06, 2019 at 10:54:22PM +0530, Srikar Dronamraju wrote: > Currently we loop through all threads of a core to evaluate if the core is > idle or not. This is unnecessary. If a thread of a core is not idle, skip > evaluating other threads of a core. Also while clearing the cpumask, bits > of all CPUs of a core can be cleared in one-shot. > > Collecting ticks on a Power 9 SMT 8 system around select_idle_core > while running schbench shows us > > (units are in ticks, hence lesser is better) > Without patch > N Min Max Median Avg Stddev > x 130 151 1083 284 322.72308 144.41494 > > > With patch > N Min Max Median Avg Stddev Improvement > x 164 88 610 201 225.79268 106.78943 30.03% > > > Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> > Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> > Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
I'm a bit surprised to not see this in linux-next or tip. Did this get rejected or did it accidentally get overlooked because the subject is so similar to 60588bfa223f ("sched/fair: Optimize select_idle_cpu") ?
-- Mel Gorman SUSE Labs
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