lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

sched: Introduce task_times() to replace task_{u,s}time() pair

Browse Source 
Functions task_{u,s}time() are called in pair in almost all
cases.  However task_stime() is implemented to call task_utime()
from its inside, so such paired calls run task_utime() twice.

It means we do heavy divisions (div_u64 + do_div) twice to get
utime and stime which can be obtained at same time by one set
of divisions.

This patch introduces a function task_times(*tsk, *utime,
*stime) to retrieve utime and stime at once in better, optimized
way.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Spencer Candland <spencer@bluehost.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
LKML-Reference: <4B0E16AE.906@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Hidetoshi Seto
2009-11-26 14:48:30 +09:00
committed by Ingo Molnar
parent 16bc67edeb
commit d180c5bcce
5 changed files with 44 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
fs/proc/array.c
View File

@@ -535,8 +535,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
if (!whole) {
min_flt = task->min_flt;
maj_flt = task->maj_flt;
utime = task_utime(task);
stime = task_stime(task);
task_times(task, &utime, &stime);
gtime = task_gtime(task);
}