From 07881166a892fa4908ac4924660a7793f75d6544 Mon Sep 17 00:00:00 2001 From: Juri Lelli Date: Mon, 4 Dec 2017 11:23:25 +0100 Subject: sched/deadline: Make bandwidth enforcement scale-invariant Apply frequency and CPU scale-invariance correction factor to bandwidth enforcement (similar to what we already do to fair utilization tracking). Each delta_exec gets scaled considering current frequency and maximum CPU capacity; which means that the reservation runtime parameter (that need to be specified profiling the task execution at max frequency on biggest capacity core) gets thus scaled accordingly. Signed-off-by: Juri Lelli Signed-off-by: Peter Zijlstra (Intel) Cc: Claudio Scordino Cc: Linus Torvalds Cc: Luca Abeni Cc: Peter Zijlstra Cc: Rafael J . Wysocki Cc: Thomas Gleixner Cc: Viresh Kumar Cc: alessio.balsini@arm.com Cc: bristot@redhat.com Cc: dietmar.eggemann@arm.com Cc: joelaf@google.com Cc: juri.lelli@redhat.com Cc: mathieu.poirier@linaro.org Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: rjw@rjwysocki.net Cc: rostedt@goodmis.org Cc: tkjos@android.com Cc: tommaso.cucinotta@santannapisa.it Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/20171204102325.5110-9-juri.lelli@redhat.com Signed-off-by: Ingo Molnar --- kernel/sched/deadline.c | 26 ++++++++++++++++++++++---- kernel/sched/fair.c | 2 -- kernel/sched/sched.h | 2 ++ 3 files changed, 24 insertions(+), 6 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 54a0dc1424a9..9bb0e0c412ec 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1151,7 +1151,8 @@ static void update_curr_dl(struct rq *rq) { struct task_struct *curr = rq->curr; struct sched_dl_entity *dl_se = &curr->dl; - u64 delta_exec; + u64 delta_exec, scaled_delta_exec; + int cpu = cpu_of(rq); if (!dl_task(curr) || !on_dl_rq(dl_se)) return; @@ -1185,9 +1186,26 @@ static void update_curr_dl(struct rq *rq) if (dl_entity_is_special(dl_se)) return; - if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM)) - delta_exec = grub_reclaim(delta_exec, rq, &curr->dl); - dl_se->runtime -= delta_exec; + /* + * For tasks that participate in GRUB, we implement GRUB-PA: the + * spare reclaimed bandwidth is used to clock down frequency. + * + * For the others, we still need to scale reservation parameters + * according to current frequency and CPU maximum capacity. + */ + if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM)) { + scaled_delta_exec = grub_reclaim(delta_exec, + rq, + &curr->dl); + } else { + unsigned long scale_freq = arch_scale_freq_capacity(cpu); + unsigned long scale_cpu = arch_scale_cpu_capacity(NULL, cpu); + + scaled_delta_exec = cap_scale(delta_exec, scale_freq); + scaled_delta_exec = cap_scale(scaled_delta_exec, scale_cpu); + } + + dl_se->runtime -= scaled_delta_exec; throttle: if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) { diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 14859757bff0..1070803cb423 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3089,8 +3089,6 @@ static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3) return c1 + c2 + c3; } -#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT) - /* * Accumulate the three separate parts of the sum; d1 the remainder * of the last (incomplete) period, d2 the span of full periods and d3 diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index e122c89bdbdd..2e95505e23c6 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -156,6 +156,8 @@ static inline int task_has_dl_policy(struct task_struct *p) return dl_policy(p->policy); } +#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT) + /* * !! For sched_setattr_nocheck() (kernel) only !! * -- cgit v1.2.3-55-g7522