Messages in this thread | | | Date | Fri, 26 Apr 2013 14:49:32 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 04/14] sched: pack the idle load balance |
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On Thu, Apr 25, 2013 at 07:23:20PM +0200, Vincent Guittot wrote: > Look for an idle CPU close to the pack buddy CPU whenever possible. > The goal is to prevent the wake up of a CPU which doesn't share the power > domain of the pack buddy CPU. > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > Reviewed-by: Morten Rasmussen <morten.rasmussen@arm.com> > --- > kernel/sched/fair.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 6adc57c..a985c98 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5469,7 +5469,26 @@ static struct { > > static inline int find_new_ilb(int call_cpu) > { > + struct sched_domain *sd; > int ilb = cpumask_first(nohz.idle_cpus_mask); > + int buddy = per_cpu(sd_pack_buddy, call_cpu); > + > + /* > + * If we have a pack buddy CPU, we try to run load balance on a CPU > + * that is close to the buddy. > + */ > + if (buddy != -1) { > + for_each_domain(buddy, sd) { > + if (sd->flags & SD_SHARE_CPUPOWER) > + continue; > + > + ilb = cpumask_first_and(sched_domain_span(sd), > + nohz.idle_cpus_mask); > + > + if (ilb < nr_cpu_ids) > + break; > + } > + } > > if (ilb < nr_cpu_ids && idle_cpu(ilb)) > return ilb;
Ha! and here you hope people won't put multiple big-little clusters in a single machine? :-)
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