On 10/04/2007 05:10 PM, Christian Borntraeger wrote:
> <patch reverting to 2.6.22 behavior>
Alternative patch:
procfs: Don't read runtime twice when computing task's stime
Current code reads p->se.sum_exec_runtime twice and goes through
multiple type conversions to calculate stime. Read it once and
skip some of the conversions.
Signed-off-by: Chuck Ebbert <[email protected]>
--- linux-2.6.23-rc6-dell.orig/fs/proc/array.c
+++ linux-2.6.23-rc6-dell/fs/proc/array.c
@@ -334,39 +334,38 @@ static cputime_t task_stime(struct task_
return p->stime;
}
#else
-static cputime_t task_utime(struct task_struct *p)
+static clock_t __task_utime(struct task_struct *p, u64 runtime)
{
clock_t utime = cputime_to_clock_t(p->utime),
total = utime + cputime_to_clock_t(p->stime);
- u64 temp;
/*
* Use CFS's precise accounting:
*/
- temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
-
if (total) {
- temp *= utime;
- do_div(temp, total);
+ runtime *= utime;
+ do_div(runtime, total);
}
- utime = (clock_t)temp;
+ return (clock_t)runtime;
+}
- return clock_t_to_cputime(utime);
+static cputime_t task_utime(struct task_struct *p)
+{
+ u64 runtime = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
+
+ return clock_t_to_cputime(__task_utime(p, runtime));
}
static cputime_t task_stime(struct task_struct *p)
{
- clock_t stime;
+ u64 runtime = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
/*
* Use CFS's precise accounting. (we subtract utime from
* the total, to make sure the total observed by userspace
* grows monotonically - apps rely on that):
*/
- stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
- cputime_to_clock_t(task_utime(p));
-
- return clock_t_to_cputime(stime);
+ return clock_t_to_cputime(runtime - __task_utime(p, runtime));
}
#endif
-
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