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Date: Thu, 19 Jul 2018 14:00:06 +0200
From: Vincent Guittot <vincent.guittot@...aro.org>
To: peterz@...radead.org, mingo@...nel.org,
linux-kernel@...r.kernel.org
Cc: rjw@...ysocki.net, viresh.kumar@...aro.org,
Vincent Guittot <vincent.guittot@...aro.org>
Subject: [PATCH] sched/fair: remove #ifdefs from scale_rt_capacity
Reuse cpu_util_irq() that has been defined for schedutil and set irq util
to 0 when !CONFIG_IRQ_TIME_ACCOUNTING
But the compiler is not able to optimize the sequence (at least with
aarch64 GCC 7.2.1)
free *= (max - irq);
free /= max;
when irq is fixed to 0
Add a new inline function scale_irq_capacity() that will scale utilization
when irq is accounted. Reuse this funciton in schedutil which applies
similar formula.
Suggested-by: Ingo Molnar <mingo@...hat.com>
Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
---
kernel/sched/cpufreq_schedutil.c | 3 +--
kernel/sched/fair.c | 13 +++----------
kernel/sched/sched.h | 20 ++++++++++++++++++--
3 files changed, 22 insertions(+), 14 deletions(-)
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 97dcd44..3fffad3 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -247,8 +247,7 @@ static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
* U' = irq + ------- * U
* max
*/
- util *= (max - irq);
- util /= max;
+ util = scale_irq_capacity(util, irq, max);
util += irq;
/*
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d5f7d52..14c3fdd 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7551,16 +7551,12 @@ static unsigned long scale_rt_capacity(int cpu)
struct rq *rq = cpu_rq(cpu);
unsigned long max = arch_scale_cpu_capacity(NULL, cpu);
unsigned long used, free;
-#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
unsigned long irq;
-#endif
-#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
- irq = READ_ONCE(rq->avg_irq.util_avg);
+ irq = cpu_util_irq(rq);
if (unlikely(irq >= max))
return 1;
-#endif
used = READ_ONCE(rq->avg_rt.util_avg);
used += READ_ONCE(rq->avg_dl.util_avg);
@@ -7569,11 +7565,8 @@ static unsigned long scale_rt_capacity(int cpu)
return 1;
free = max - used;
-#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
- free *= (max - irq);
- free /= max;
-#endif
- return free;
+
+ return scale_irq_capacity(free, irq, max);
}
static void update_cpu_capacity(struct sched_domain *sd, int cpu)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index ebb4b3c..b80c3fd 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2210,17 +2210,33 @@ static inline unsigned long cpu_util_rt(struct rq *rq)
{
return READ_ONCE(rq->avg_rt.util_avg);
}
+#endif
-#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
+#if defined(SMP) \
+ && (defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING))
static inline unsigned long cpu_util_irq(struct rq *rq)
{
return rq->avg_irq.util_avg;
}
+
+static inline
+unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max)
+{
+ util *= (max - irq);
+ util /= max;
+
+ return util;
+
+}
#else
static inline unsigned long cpu_util_irq(struct rq *rq)
{
return 0;
}
-#endif
+static inline
+unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max)
+{
+ return util;
+}
#endif
--
2.7.4
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