Messages in this thread Patch in this message | | | Date | Sun, 29 Nov 2009 13:01:48 +0100 | From | Tim Blechmann <> | Subject | [PATCH] sched: Optimize branch hint in context_switch() |
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Branch hint profiling on my nehalem machine showed 88% incorrect branch hints:
42017484 326957902 88 context_switch sched.c 3043 42038493 326953687 88 context_switch sched.c 3050
Signed-off-by: Tim Blechmann <tim@klingt.org> --- kernel/sched.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c index 2a78b38..c78dcfe 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3040,14 +3040,14 @@ context_switch(struct rq *rq, struct task_struct *prev, */ arch_start_context_switch(prev); - if (likely(!mm)) { + if (unlikely(!mm)) { next->active_mm = oldmm; atomic_inc(&oldmm->mm_count); enter_lazy_tlb(oldmm, next); } else switch_mm(oldmm, mm, next); - if (likely(!prev->mm)) { + if (unlikely(!prev->mm)) { prev->active_mm = NULL; rq->prev_mm = oldmm; } [unhandled content-type:application/pgp-signature]
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