Messages in this thread Patch in this message | | | Date | Mon, 13 Dec 2010 20:28:06 -0500 | From | Steven Rostedt <> | Subject | [PATCH 3/4] sched: Remove unlikely() from rt_policy() in sched.c |
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From: Steven Rostedt <srostedt@redhat.com>
The rt_policy() has an unlikely() that the policy it is checking is of RT priority (SCHED_FIFO or SCHED_RR).
According to the annotate branch profiler it is incorrect most of the time:
correct incorrect % Function File Line ------- --------- - -------- ---- ---- 36667 654674 94 rt_policy sched.c 126
This makes sense because the rt_policy() is used by the sched_set_scheduler() and nice(). Although users may use sys_nice a bit, all RT users use the sched_set_scheduler() to set their RT priority, including kernel threads.
The above numbers were from a normal desktop computer running firefox, evolution, xchat and was part of a distcc compile farm.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- kernel/sched.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c index dc91a4d..269a045 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -123,7 +123,7 @@ static inline int rt_policy(int policy) { - if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR)) + if (policy == SCHED_FIFO || policy == SCHED_RR) return 1; return 0; } -- 1.7.2.3
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