Commit-ID: 594dd290cf5403a9a5818619dfff42d8e8e0518e Gitweb: http://git.kernel.org/tip/594dd290cf5403a9a5818619dfff42d8e8e0518e Author: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> AuthorDate: Fri, 22 Apr 2016 17:07:24 +0800 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Thu, 28 Apr 2016 10:39:54 +0200 sched/cpufreq: Optimize cpufreq update kicker to avoid update multiple times Sometimes delta_exec is 0 due to update_curr() is called multiple times, this is captured by: u64 delta_exec = rq_clock_task(rq) - curr->se.exec_start; This patch optimizes the cpufreq update kicker by bailing out when nothing changed, it will benefit the upcoming schedutil, since otherwise it will (over)react to the special util/max combination. Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1461316044-9520-1-git-send-email-wanpeng.li@xxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- kernel/sched/deadline.c | 8 ++++---- kernel/sched/rt.c | 8 ++++---- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index affd97e..8f9b5af 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -717,10 +717,6 @@ static void update_curr_dl(struct rq *rq) if (!dl_task(curr) || !on_dl_rq(dl_se)) return; - /* Kick cpufreq (see the comment in linux/cpufreq.h). */ - if (cpu_of(rq) == smp_processor_id()) - cpufreq_trigger_update(rq_clock(rq)); - /* * Consumed budget is computed considering the time as * observed by schedulable tasks (excluding time spent @@ -736,6 +732,10 @@ static void update_curr_dl(struct rq *rq) return; } + /* kick cpufreq (see the comment in linux/cpufreq.h). */ + if (cpu_of(rq) == smp_processor_id()) + cpufreq_trigger_update(rq_clock(rq)); + schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec)); diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index c41ea7a..19e1306 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -953,14 +953,14 @@ static void update_curr_rt(struct rq *rq) if (curr->sched_class != &rt_sched_class) return; - /* Kick cpufreq (see the comment in linux/cpufreq.h). */ - if (cpu_of(rq) == smp_processor_id()) - cpufreq_trigger_update(rq_clock(rq)); - delta_exec = rq_clock_task(rq) - curr->se.exec_start; if (unlikely((s64)delta_exec <= 0)) return; + /* Kick cpufreq (see the comment in linux/cpufreq.h). */ + if (cpu_of(rq) == smp_processor_id()) + cpufreq_trigger_update(rq_clock(rq)); + schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec)); -- 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
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