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| author | Dietmar Eggemann <dietmar.eggemann@arm.com> | 2015-09-07 15:57:22 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-09-13 09:53:01 +0200 |
| commit | 6f2b04524f0b38bfbb8413f98d2d6af234508309 (patch) | |
| tree | 9801d81b972f0993fdd2fdbe05e03dca4a27943c /kernel/sched/fair.c | |
| parent | sched/fair: Optimize __update_load_avg() (diff) | |
| download | linux-6f2b04524f0b38bfbb8413f98d2d6af234508309.tar.xz linux-6f2b04524f0b38bfbb8413f98d2d6af234508309.zip | |
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>
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c3c5585292a6..fc835fa23308 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) { |