On Fri, 2013-03-22 at 13:25 +0100, 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 | 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 ona 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;}
/me hands you a fresh bucket of curlies, no reason to skimp on them.
But ha! here's your NO_HZ link.. but does the above DTRT and ensure that the ILB is a little core when possible?