Messages in this thread | | | Date | Fri, 24 Jan 2020 19:02:13 +0530 | From | Srikar Dronamraju <> | Subject | Re: [PATCH v2] sched/fair: Optimize select_idle_core |
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Hey Peter, Ingo,
* Srikar Dronamraju <srikar@linux.vnet.ibm.com> [2019-12-06 22:54:22]:
> 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> > --- > Changelog v1->v2: > Updated patch description with measurements made from a debug patch. > > kernel/sched/fair.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-)
Do you have any comments or improvements to be done for this patch?
-- Thanks and Regards Srikar Dronamraju
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