From 23cfa361f3e54a3e184a5e126bbbdd95f984881a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 12 Nov 2014 12:37:37 +0100 Subject: 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) Cc: KOSAKI Motohiro Cc: Oleg Nesterov Cc: Stanislaw Gruszka Cc: Christoph Lameter Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Rik van Riel Cc: Tejun Heo Link: http://lkml.kernel.org/r/20141112113737.GI10476@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 13 ------------- kernel/time/posix-cpu-timers.c | 2 +- 2 files changed, 1 insertion(+), 14 deletions(-) (limited to 'kernel') 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; -- cgit v1.2.3