lkml.org 
[lkml]   [2015]   [Sep]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:sched/core] sched/fair: Defer calling scaling functions
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) {

\
 
 \ /
  Last update: 2015-09-13 13:21    [W:0.077 / U:2.332 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site