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authorPeter Zijlstra <peterz@infradead.org>2014-11-12 12:37:37 +0100
committerIngo Molnar <mingo@kernel.org>2014-11-16 10:04:18 +0100
commit23cfa361f3e54a3e184a5e126bbbdd95f984881a (patch)
tree05586994df46de68033653c1180f081ed45ae0be
parent7af683350cb0ddd0e9d3819b4eb7abe9e2d3e709 (diff)
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@infradead.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rik van Riel <riel@redhat.com> Cc: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/20141112113737.GI10476@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--include/linux/kernel_stat.h5
-rw-r--r--kernel/sched/core.c13
-rw-r--r--kernel/time/posix-cpu-timers.c2
3 files changed, 1 insertions, 19 deletions
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 8422b4ed6882..b9376cd5a187 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 5f12ca65c9a7..797a6c84c48d 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 492b986195d5..a16b67859e2a 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;