From mboxrd@z Thu Jan 1 00:00:00 1970 From: vincent.guittot@linaro.org (Vincent Guittot) Date: Fri, 22 Mar 2013 13:25:54 +0100 Subject: [RFC PATCH v3 5/6] sched: pack the idle load balance In-Reply-To: <1363955155-18382-1-git-send-email-vincent.guittot@linaro.org> References: <1363955155-18382-1-git-send-email-vincent.guittot@linaro.org> Message-ID: <1363955155-18382-6-git-send-email-vincent.guittot@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Reviewed-by: Morten Rasmussen --- kernel/sched/fair.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index b636199..52a7736 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5455,7 +5455,25 @@ 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; + + 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; -- 1.7.9.5