Commit-ID: 23cfa361f3e54a3e184a5e126bbbdd95f984881a
Gitweb: http://git.kernel.org/tip/23cfa361f3e54a3e184a5e126bbbdd95f984881a
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 12 Nov 2014 12:37:37 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 16 Nov 2014 10:04:18 +0100
sched/cputime: Fix cpu_timer_sample_group() double accounting
While looking over the cpu-timer code I found that we appear to add
the delta for the calling task twice, through:
cpu_timer_sample_group()
thread_group_cputimer()
thread_group_cputime()
times->sum_exec_runtime += task_sched_runtime();
*sample = cputime.sum_exec_runtime + task_delta_exec();
Which would make the sample run ahead, making the sleep short.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20141112113737.GI10476@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/kernel_stat.h | 5 -----
kernel/sched/core.c | 13 -------------
kernel/time/posix-cpu-timers.c | 2 +-
3 files changed, 1 insertion(+), 19 deletions(-)
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 8422b4e..b9376cd 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -77,11 +77,6 @@ static inline unsigned int kstat_cpu_irqs_sum(unsigned int cpu)
return kstat_cpu(cpu).irqs_sum;
}
-/*
- * Lock/unlock the current runqueue - to extract task statistics:
- */
-extern unsigned long long task_delta_exec(struct task_struct *);
-
extern void account_user_time(struct task_struct *, cputime_t, cputime_t);
extern void account_system_time(struct task_struct *, int, cputime_t, cputime_t);
extern void account_steal_time(cputime_t);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5f12ca6..797a6c8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2499,19 +2499,6 @@ static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
return ns;
}
-unsigned long long task_delta_exec(struct task_struct *p)
-{
- unsigned long flags;
- struct rq *rq;
- u64 ns = 0;
-
- rq = task_rq_lock(p, &flags);
- ns = do_task_delta_exec(p, rq);
- task_rq_unlock(rq, p, &flags);
-
- return ns;
-}
-
/*
* Return accounted runtime for the task.
* In case the task is currently running, return the runtime plus current's
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 492b986..a16b678 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -553,7 +553,7 @@ static int cpu_timer_sample_group(const clockid_t which_clock,
*sample = cputime_to_expires(cputime.utime);
break;
case CPUCLOCK_SCHED:
- *sample = cputime.sum_exec_runtime + task_delta_exec(p);
+ *sample = cputime.sum_exec_runtime;
break;
}
return 0;
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|