Messages in this thread | | | Date | Fri, 2 Nov 2012 16:29:07 +0530 | From | Santosh Shilimkar <> | Subject | Re: [RFC 5/6] sched: pack the idle load balance |
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On Monday 29 October 2012 06:57 PM, Vincent Guittot wrote: > On 24 October 2012 17:21, Santosh Shilimkar <santosh.shilimkar@ti.com> wrote: >> On Sunday 07 October 2012 01:13 PM, Vincent Guittot wrote: >>> >>> Look for an idle CPU close the pack buddy CPU whenever possible. >> >> s/close/close to > > yes > >> >>> The goal is to prevent the wake up of a CPU which doesn't share the power >>> line of the pack CPU >>> >>> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> >>> --- >>> kernel/sched/fair.c | 18 ++++++++++++++++++ >>> 1 file changed, 18 insertions(+) >>> >>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >>> index 6df53b5..f76acdc 100644 >>> --- a/kernel/sched/fair.c >>> +++ b/kernel/sched/fair.c >>> @@ -5158,7 +5158,25 @@ 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; >> >> Do you mean SD_SHARE_POWERLINE here ? > > No, I just don't want to take hyperthread level for ILB > >> >>> + >>> + 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; >>> >> Can you please expand "idle CPU _close_ the pack buddy CPU" ? > > The goal is to packed the tasks on the pack buddy CPU so when the > scheduler needs to start ILB, I try to wake up a CPU that is close to > the buddy and preferably in the same cluster > I see your point now. Thanks for clarification.
Regards santosh
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