Messages in this thread Patch in this message | | | From | Namhyung Kim <> | Subject | [RFC/PATCH] sched: Honor sync wake up in select_idle_sibling | Date | Fri, 10 Aug 2012 16:25:12 +0900 |
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From: Namhyung Kim <namhyung.kim@lge.com>
When sync wakeup happens and there's the waker task running alone, select the target cpu as if it's already idle.
Cc: Mike Galbraith <efault@gmx.de> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- kernel/sched/fair.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index d0cc03b3e70b..64b68bc82b52 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2632,7 +2632,7 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) /* * Try and locate an idle CPU in the sched_domain. */ -static int select_idle_sibling(struct task_struct *p, int target) +static int select_idle_sibling(struct task_struct *p, int target, int sync) { int cpu = smp_processor_id(); int prev_cpu = task_cpu(p); @@ -2646,6 +2646,13 @@ static int select_idle_sibling(struct task_struct *p, int target) return cpu; /* + * If the task is going to be woken-up on this cpu and there's only + * the sync-waker running, then it is the right target. + */ + if (target == cpu && sync && this_rq()->nr_running == 1) + return cpu; + + /* * If the task is going to be woken-up on the cpu where it previously * ran and if it is currently idle, then it the right target. */ @@ -2748,7 +2755,7 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) if (cpu == prev_cpu || wake_affine(affine_sd, p, sync)) prev_cpu = cpu; - new_cpu = select_idle_sibling(p, prev_cpu); + new_cpu = select_idle_sibling(p, prev_cpu, sync); goto unlock; } -- 1.7.11.2
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