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sched: Remove unlikely() from ttwu_post_activation
The unlikely() used in ttwu_post_activation() tests if the rq->idle_stamp is set. But since this is for a wakeup, and wakeups happen when tasks block on IO, and blocking tasks on IO may put the system into idle, this can actually be a common occurence. Running the annotated branch profiler on an average desktop running firefox, evolution, xchat and distcc, the report shows: correct incorrect % Function File Line ------- --------- - -------- ---- ---- 34884862 146110926 80 ttwu_post_activation sched.c 2309 80% of the time, this unlikely is incorrect. Best not to assume what the result is, and just remove the branch annotation. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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@ -2458,7 +2458,7 @@ static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq,
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if (p->sched_class->task_woken)
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p->sched_class->task_woken(rq, p);
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if (unlikely(rq->idle_stamp)) {
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if (rq->idle_stamp) {
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u64 delta = rq->clock - rq->idle_stamp;
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u64 max = 2*sysctl_sched_migration_cost;
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