Commit-ID: 282cf499f03ec1754b6c8c945c9674b02631fb0f Gitweb: http://git.kernel.org/tip/282cf499f03ec1754b6c8c945c9674b02631fb0f Author: Alex Shi <alex....@intel.com> AuthorDate: Thu, 20 Jun 2013 10:18:48 +0800 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 27 Jun 2013 10:07:32 +0200
sched: Fix sleep time double accounting in enqueue entity The woken migrated task will __synchronize_entity_decay(se); in migrate_task_rq_fair, then it needs to set `se->avg.last_runnable_update -= (-se->avg.decay_count) << 20' before update_entity_load_avg, in order to avoid sleep time is updated twice for se.avg.load_avg_contrib in both __syncchronize and update_entity_load_avg. However if the sleeping task is woken up from the same cpu, it miss the last_runnable_update before update_entity_load_avg(se, 0, 1), then the sleep time was used twice in both functions. So we need to remove the double sleep time accounting. Paul also contributed some code comments in this commit. Signed-off-by: Alex Shi <alex....@intel.com> Reviewed-by: Paul Turner <p...@google.com> Signed-off-by: Peter Zijlstra <pet...@infradead.org> Link: http://lkml.kernel.org/r/1371694737-29336-5-git-send-email-alex....@intel.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/sched/fair.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e1602a0..9bbc303 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1571,7 +1571,13 @@ static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq, } wakeup = 0; } else { - __synchronize_entity_decay(se); + /* + * Task re-woke on same cpu (or else migrate_task_rq_fair() + * would have made count negative); we must be careful to avoid + * double-accounting blocked time after synchronizing decays. + */ + se->avg.last_runnable_update += __synchronize_entity_decay(se) + << 20; } /* migrated tasks did not contribute to our blocked load */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
