diff options
author | Jason Low <jason.low2@hp.com> | 2015-10-14 15:07:53 -0400 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2015-10-15 05:23:41 -0400 |
commit | 7c177d994eb9637302b79e80d331f48dfbe26368 (patch) | |
tree | c5160894bfb1ea109d73e45e2d3dc066c69cd24b /kernel/time/posix-cpu-timers.c | |
parent | 6035519fcf5aa17084b41790cdc584d881d82c03 (diff) |
posix_cpu_timer: Optimize fastpath_timer_check()
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>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: George Spelvin <linux@horizon.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: hideaki.kimura@hpe.com
Cc: terry.rudd@hpe.com
Cc: scott.norton@hpe.com
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1444849677-29330-2-git-send-email-jason.low2@hp.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time/posix-cpu-timers.c')
-rw-r--r-- | kernel/time/posix-cpu-timers.c | 11 |
1 files changed, 3 insertions, 8 deletions
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 892e3dae0aac..aa4b6f4f3b5e 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c | |||
@@ -1117,17 +1117,12 @@ static inline int task_cputime_expired(const struct task_cputime *sample, | |||
1117 | static inline int fastpath_timer_check(struct task_struct *tsk) | 1117 | static inline int fastpath_timer_check(struct task_struct *tsk) |
1118 | { | 1118 | { |
1119 | struct signal_struct *sig; | 1119 | struct signal_struct *sig; |
1120 | cputime_t utime, stime; | ||
1121 | |||
1122 | task_cputime(tsk, &utime, &stime); | ||
1123 | 1120 | ||
1124 | if (!task_cputime_zero(&tsk->cputime_expires)) { | 1121 | if (!task_cputime_zero(&tsk->cputime_expires)) { |
1125 | struct task_cputime task_sample = { | 1122 | struct task_cputime task_sample; |
1126 | .utime = utime, | ||
1127 | .stime = stime, | ||
1128 | .sum_exec_runtime = tsk->se.sum_exec_runtime | ||
1129 | }; | ||
1130 | 1123 | ||
1124 | task_cputime(tsk, &task_sample.utime, &task_sample.stime); | ||
1125 | task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime; | ||
1131 | if (task_cputime_expired(&task_sample, &tsk->cputime_expires)) | 1126 | if (task_cputime_expired(&task_sample, &tsk->cputime_expires)) |
1132 | return 1; | 1127 | return 1; |
1133 | } | 1128 | } |