Commit-ID: 63f01241176d7cbc976385aec32f0a209b0bc36a
Gitweb: http://git.kernel.org/tip/63f01241176d7cbc976385aec32f0a209b0bc36a
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Mon, 6 Dec 2010 14:48:10 -0500
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Mon, 13 Dec 2010 19:56:40 -0500
sched: Remove unlikely() from rt_policy() in sched.c
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@xxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
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;
}
--
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