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sched: make use of precise accounting for /proc task stats 

make use of CFS's precise accounting to drive /proc/<pid>/stat statistics.

this code was co-authored by:

 Balbir Singh <balbir@linux.vnet.ibm.com>
 Dmitry Adamushko <dmitry.adamushko@gmail.com>
 Ingo Molnar <mingo@elte.hu>

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
This commit is contained in:
Ingo Molnar 2007-07-09 18:51:59 +02:00
parent 1b9f19c212
commit b27f03d4bd
1 changed files with 47 additions and 10 deletions
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57
fs/proc/array.c
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@ -310,6 +310,41 @@ int proc_pid_status(struct task_struct *task, char * buffer)
return buffer - orig;
}
static clock_t task_utime(struct task_struct *p)
{
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);
}
utime = (clock_t)temp;
return utime;
}
static clock_t task_stime(struct task_struct *p)
{
clock_t stime = cputime_to_clock_t(p->stime);
/*
* 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) - task_utime(p);
return stime;
}
static int do_task_stat(struct task_struct *task, char * buffer, int whole)
{
unsigned long vsize, eip, esp, wchan = ~0UL;
@ -324,7 +359,8 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
unsigned long long start_time;
unsigned long cmin_flt = 0, cmaj_flt = 0;
unsigned long min_flt = 0, maj_flt = 0;
cputime_t cutime, cstime, utime, stime;
cputime_t cutime, cstime;
clock_t utime, stime;
unsigned long rsslim = 0;
char tcomm[sizeof(task->comm)];
unsigned long flags;
@ -342,7 +378,8 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
sigemptyset(&sigign);
sigemptyset(&sigcatch);
cutime = cstime = utime = stime = cputime_zero;
cutime = cstime = cputime_zero;
utime = stime = 0;
rcu_read_lock();
if (lock_task_sighand(task, &flags)) {
@ -368,15 +405,15 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
do {
min_flt += t->min_flt;
maj_flt += t->maj_flt;
utime = cputime_add(utime, t->utime);
stime = cputime_add(stime, t->stime);
utime += task_utime(t);
stime += task_stime(t);
t = next_thread(t);
} while (t != task);
min_flt += sig->min_flt;
maj_flt += sig->maj_flt;
utime = cputime_add(utime, sig->utime);
stime = cputime_add(stime, sig->stime);
utime += cputime_to_clock_t(sig->utime);
stime += cputime_to_clock_t(sig->stime);
}
sid = signal_session(sig);
@ -392,8 +429,8 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
if (!whole) {
min_flt = task->min_flt;
maj_flt = task->maj_flt;
utime = task->utime;
stime = task->stime;
utime = task_utime(task);
stime = task_stime(task);
}
/* scale priority and nice values from timeslices to -20..20 */
@ -424,8 +461,8 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
cmin_flt,
maj_flt,
cmaj_flt,
cputime_to_clock_t(utime),
cputime_to_clock_t(stime),
utime,
stime,
cputime_to_clock_t(cutime),
cputime_to_clock_t(cstime),
priority,