Messages in this thread Patch in this message | | | Date | Sun, 13 Sep 2015 04:06:17 -0700 | From | tip-bot for Dietmar Eggemann <> | Subject | [tip:sched/core] sched/fair: Defer calling scaling functions |
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Commit-ID: 6f2b04524f0b38bfbb8413f98d2d6af234508309 Gitweb: http://git.kernel.org/tip/6f2b04524f0b38bfbb8413f98d2d6af234508309 Author: Dietmar Eggemann <dietmar.eggemann@arm.com> AuthorDate: Mon, 7 Sep 2015 14:57:22 +0100 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Sun, 13 Sep 2015 09:53:01 +0200
sched/fair: Defer calling scaling functions
Do not call the scaling functions in case time goes backwards or the last update of the sched_avg structure has happened less than 1024ns ago.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <Juri.Lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: daniel.lezcano@linaro.org <daniel.lezcano@linaro.org> Cc: mturquette@baylibre.com <mturquette@baylibre.com> Cc: pang.xunlei@zte.com.cn <pang.xunlei@zte.com.cn> Cc: rjw@rjwysocki.net <rjw@rjwysocki.net> Cc: sgurrappadi@nvidia.com <sgurrappadi@nvidia.com> Cc: vincent.guittot@linaro.org <vincent.guittot@linaro.org> Cc: yuyang.du@intel.com <yuyang.du@intel.com> Link: http://lkml.kernel.org/r/55EDA2E9.8040900@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/sched/fair.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c3c5585..fc835fa 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2552,8 +2552,7 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa, u64 delta, scaled_delta, periods; u32 contrib; unsigned int delta_w, scaled_delta_w, decayed = 0; - unsigned long scale_freq = arch_scale_freq_capacity(NULL, cpu); - unsigned long scale_cpu = arch_scale_cpu_capacity(NULL, cpu); + unsigned long scale_freq, scale_cpu; delta = now - sa->last_update_time; /* @@ -2574,6 +2573,9 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa, return 0; sa->last_update_time = now; + scale_freq = arch_scale_freq_capacity(NULL, cpu); + scale_cpu = arch_scale_cpu_capacity(NULL, cpu); + /* delta_w is the amount already accumulated against our next period */ delta_w = sa->period_contrib; if (delta + delta_w >= 1024) {
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