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sched: Remove unlikely() from rt_policy() in sched.c
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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>
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Steven Rostedt authored and Steven Rostedt committed Dec 14, 2010
1 parent 8e54a2c commit 63f0124
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion kernel/sched.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
}
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