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| author | Wanpeng Li <wanpeng.li@hotmail.com> | 2016-04-22 17:07:24 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-04-28 10:39:54 +0200 |
| commit | 594dd290cf5403a9a5818619dfff42d8e8e0518e (patch) | |
| tree | 31fa5c3c77c6c5cc293a91bd85cef310f0b988e6 /kernel/sched/rt.c | |
| parent | fec148c000d0f9ac21679601722811eb60b4cc52 (diff) | |
| download | linux-594dd290cf5403a9a5818619dfff42d8e8e0518e.tar.bz2 | |
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@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1461316044-9520-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/rt.c')
| -rw-r--r-- | kernel/sched/rt.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index c41ea7ac1764..19e13060fcd5 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)); |