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authorIngo Molnar <mingo@elte.hu>2007-07-09 18:51:59 +0200
committerIngo Molnar <mingo@elte.hu>2007-07-09 18:51:59 +0200
commitb27f03d4bdc145a09fb7b0c0e004b29f1ee555fa (patch)
tree37b918b7dcc548671db53d4f3c2fdc673939e086
parent1b9f19c2125dd1021b9327111dc40b14b557ee12 (diff)
downloadlinux-2.6.34-ux500-b27f03d4bdc145a09fb7b0c0e004b29f1ee555fa.tar.gz
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>
-rw-r--r--fs/proc/array.c57
1 files changed, 47 insertions, 10 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 3df644313f9..98e78e2f18d 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -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,