lkml.org 
[lkml]   [2015]   [Aug]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/3] timer: Optimize fastpath_timer_check()
Date
In fastpath_timer_check(), the task_cputime() function is always
called to compute the utime and stime values. However, this is not
necessary if there are no per-thread timers to check for. This patch
modifies the code such that we compute the task_cputime values only
when there are per-thread timers set.

Signed-off-by: Jason Low <jason.low2@hp.com>
---
kernel/time/posix-cpu-timers.c | 15 +++++++--------
1 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 892e3da..02596ff 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -1117,16 +1117,15 @@ static inline int task_cputime_expired(const struct task_cputime *sample,
static inline int fastpath_timer_check(struct task_struct *tsk)
{
struct signal_struct *sig;
- cputime_t utime, stime;
-
- task_cputime(tsk, &utime, &stime);

if (!task_cputime_zero(&tsk->cputime_expires)) {
- struct task_cputime task_sample = {
- .utime = utime,
- .stime = stime,
- .sum_exec_runtime = tsk->se.sum_exec_runtime
- };
+ struct task_cputime task_sample;
+ cputime_t utime, stime;
+
+ task_cputime(tsk, &utime, &stime);
+ task_sample.utime = utime;
+ task_sample.stime = stime;
+ task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime;

if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
return 1;
--
1.7.2.5


\
 
 \ /
  Last update: 2015-08-26 05:41    [W:0.224 / U:22.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site