Commit-ID: e0367b12674bf4420870cd0237e3ebafb2ec9593 Gitweb: https://git.kernel.org/tip/e0367b12674bf4420870cd0237e3ebafb2ec9593 Author: Juri Lelli <juri.le...@arm.com> AuthorDate: Mon, 4 Dec 2017 11:23:19 +0100 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Wed, 10 Jan 2018 11:30:32 +0100
sched/deadline: Move CPU frequency selection triggering points Since SCHED_DEADLINE doesn't track utilization signal (but reserves a fraction of CPU bandwidth to tasks admitted to the system), there is no point in evaluating frequency changes during each tick event. Move frequency selection triggering points to where running_bw changes. Co-authored-by: Claudio Scordino <clau...@evidence.eu.com> Signed-off-by: Juri Lelli <juri.le...@arm.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Reviewed-by: Viresh Kumar <viresh.ku...@linaro.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Luca Abeni <luca.ab...@santannapisa.it> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wyso...@intel.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: alessio.bals...@arm.com Cc: bris...@redhat.com Cc: dietmar.eggem...@arm.com Cc: joe...@google.com Cc: juri.le...@redhat.com Cc: mathieu.poir...@linaro.org Cc: morten.rasmus...@arm.com Cc: patrick.bell...@arm.com Cc: r...@rjwysocki.net Cc: rost...@goodmis.org Cc: tk...@android.com Cc: tommaso.cucino...@santannapisa.it Cc: vincent.guit...@linaro.org Link: http://lkml.kernel.org/r/20171204102325.5110-3-juri.le...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/sched/deadline.c | 7 ++++--- kernel/sched/sched.h | 12 ++++++------ 2 files changed, 10 insertions(+), 9 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 4c666db..f584837 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -86,6 +86,8 @@ void add_running_bw(u64 dl_bw, struct dl_rq *dl_rq) dl_rq->running_bw += dl_bw; SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */ SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw); + /* kick cpufreq (see the comment in kernel/sched/sched.h). */ + cpufreq_update_util(rq_of_dl_rq(dl_rq), SCHED_CPUFREQ_DL); } static inline @@ -98,6 +100,8 @@ void sub_running_bw(u64 dl_bw, struct dl_rq *dl_rq) SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */ if (dl_rq->running_bw > old) dl_rq->running_bw = 0; + /* kick cpufreq (see the comment in kernel/sched/sched.h). */ + cpufreq_update_util(rq_of_dl_rq(dl_rq), SCHED_CPUFREQ_DL); } static inline @@ -1134,9 +1138,6 @@ static void update_curr_dl(struct rq *rq) return; } - /* kick cpufreq (see the comment in kernel/sched/sched.h). */ - cpufreq_update_util(rq, SCHED_CPUFREQ_DL); - schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec)); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 136ab50..863964f 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2055,14 +2055,14 @@ DECLARE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); * The way cpufreq is currently arranged requires it to evaluate the CPU * performance state (frequency/voltage) on a regular basis to prevent it from * being stuck in a completely inadequate performance level for too long. - * That is not guaranteed to happen if the updates are only triggered from CFS, - * though, because they may not be coming in if RT or deadline tasks are active - * all the time (or there are RT and DL tasks only). + * That is not guaranteed to happen if the updates are only triggered from CFS + * and DL, though, because they may not be coming in if only RT tasks are + * active all the time (or there are RT tasks only). * - * As a workaround for that issue, this function is called by the RT and DL - * sched classes to trigger extra cpufreq updates to prevent it from stalling, + * As a workaround for that issue, this function is called periodically by the + * RT sched class to trigger extra cpufreq updates to prevent it from stalling, * but that really is a band-aid. Going forward it should be replaced with - * solutions targeted more specifically at RT and DL tasks. + * solutions targeted more specifically at RT tasks. */ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {
