Re: [PATCH v2 02/11] sched: remove a wake_affine condition

On Fri, May 23, 2014 at 05:52:56PM +0200, Vincent Guittot wrote:

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 9587ed1..30240ab 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4238,7 +4238,6 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) { s64 this_load, load; int idx, this_cpu, prev_cpu;

• unsigned long tl_per_task; struct task_group *tg; unsigned long weight; int balanced;

@@ -4296,32 +4295,22 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) balanced = this_eff_load <= prev_eff_load; } else balanced = true;

• schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts);

• if (!balanced)

• return 0;
  

  /*
  • If the currently running task will sleep within
  • a reasonable amount of time then attract this newly
  • woken task:
  */
• if (sync) return 1;

• schedstat_inc(sd, ttwu_move_affine);
• schedstat_inc(p, se.statistics.nr_wakeups_affine);

• return 1;

}

So I'm not usually one for schedstat nitpicking, but should we fix it in the sync case? That is, for sync we return 1 but do no inc nr_wakeups_affine, even though its going to be an affine wakeup.