Commit-ID: 594dd290cf5403a9a5818619dfff42d8e8e0518e
Gitweb: http://git.kernel.org/tip/594dd290cf5403a9a5818619dfff42d8e8e0518e
Author: Wanpeng Li <wanpeng...@hotmail.com>
AuthorDate: Fri, 22 Apr 2016 17:07:24 +0800
Committer: Ingo Molnar <mi...@kernel.org>
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...@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Link:
http://lkml.kernel.org/r/1461316044-9520-1-git-send-email-wanpeng...@hotmail.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
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));
