Messages in this thread Patch in this message | | | From | Vincent Guittot <> | Subject | [PATCH] sched/fair: remove #ifdefs from scale_rt_capacity | Date | Thu, 19 Jul 2018 14:00:06 +0200 |
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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@redhat.com> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.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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