lkml.org 
[lkml]   [2015]   [Jun]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v3 4/4] [RFC] sched: cfs: cpu frequency scaling policy
Date
From: Michael Turquette <mturquette@baylibre.com>

Implements a very simple policy to scale cpu frequency as a function of
cfs utilization. This policy is a placeholder until something better
comes along. Its purpose is to illustrate how to use the
cpufreq_sched_set_capacity api and allow interested parties to hack on
this stuff.

Signed-off-by: Michael Turquette <mturquette@baylibre.com>
---
Changes in v3:
Split out into separate patch
Capacity calculation moved from cpufreq governor to cfs
Removed use of static key. Replaced with Kconfig option

kernel/sched/fair.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 46855d0..5ccc384 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4217,6 +4217,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
{
struct cfs_rq *cfs_rq;
struct sched_entity *se = &p->se;
+ unsigned long utilization, capacity;

for_each_sched_entity(se) {
if (se->on_rq)
@@ -4252,6 +4253,19 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
update_rq_runnable_avg(rq, rq->nr_running);
add_nr_running(rq, 1);
}
+
+#ifdef CONFIG_CPU_FREQ_GOV_SCHED
+ /* add 25% margin to current utilization */
+ utilization = rq->cfs.utilization_load_avg;
+ capacity = utilization + (utilization >> 2);
+
+ /* handle rounding errors */
+ capacity = (capacity > SCHED_LOAD_SCALE) ? SCHED_LOAD_SCALE :
+ capacity;
+
+ cpufreq_sched_set_cap(cpu_of(rq), capacity);
+#endif
+
hrtick_update(rq);
}

@@ -4267,6 +4281,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
struct cfs_rq *cfs_rq;
struct sched_entity *se = &p->se;
int task_sleep = flags & DEQUEUE_SLEEP;
+ unsigned long utilization, capacity;

for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
@@ -4313,6 +4328,19 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
sub_nr_running(rq, 1);
update_rq_runnable_avg(rq, 1);
}
+
+#ifdef CONFIG_CPU_FREQ_GOV_SCHED
+ /* add 25% margin to current utilization */
+ utilization = rq->cfs.utilization_load_avg;
+ capacity = utilization + (utilization >> 2);
+
+ /* handle rounding errors */
+ capacity = (capacity > SCHED_LOAD_SCALE) ? SCHED_LOAD_SCALE :
+ capacity;
+
+ cpufreq_sched_set_cap(cpu_of(rq), capacity);
+#endif
+
hrtick_update(rq);
}

@@ -7806,6 +7834,7 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
{
struct cfs_rq *cfs_rq;
struct sched_entity *se = &curr->se;
+ unsigned long utilization, capacity;

for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
@@ -7816,6 +7845,18 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
task_tick_numa(rq, curr);

update_rq_runnable_avg(rq, 1);
+
+#ifdef CONFIG_CPU_FREQ_GOV_SCHED
+ /* add 25% margin to current utilization */
+ utilization = rq->cfs.utilization_load_avg;
+ capacity = utilization + (utilization >> 2);
+
+ /* handle rounding errors */
+ capacity = (capacity > SCHED_LOAD_SCALE) ? SCHED_LOAD_SCALE :
+ capacity;
+
+ cpufreq_sched_set_cap(cpu_of(rq), capacity);
+#endif
}

/*
--
1.9.1


\
 
 \ /
  Last update: 2015-06-27 02:21    [W:0.065 / U:0.528 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site