Messages in this thread Patch in this message | | | Subject | [sched/rt] Optimization of function pull_rt_task() | From | Kirill Tkhai <> | Date | Sun, 15 Apr 2012 23:45:22 +0400 |
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The condition (src_rq->rt.rt_nr_running) is weak because it doesn't consider the cases when src_rq has only processes bound to it (when single cpu is allowed). It may be running kernel thread like migration/x etc.
So it's better to use more stronger condition which is able to exclude above conditions. The function has_pushable_tasks() complitely does this. A task may be pullable for another cpu rq only if he is pushable for his own queue.
Signed-off-by: Kirill Tkhai <tkhai@yandex.ru> --- kernel/sched/rt.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index c5565c3..61e3086 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1729,7 +1729,7 @@ static int pull_rt_task(struct rq *this_rq) /* * Are there still pullable RT tasks? */ - if (src_rq->rt.rt_nr_running <= 1) + if (!has_pushable_tasks(src_rq)) goto skip; p = pick_next_highest_task_rt(src_rq, this_cpu);
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