diff options
| author | Morten Rasmussen <morten.rasmussen@arm.com> | 2016-10-14 16:41:09 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-11-16 12:29:06 +0300 |
| commit | bf475ce0a3dd75b5d1df6c6c14ae25168caa15ac (patch) | |
| tree | 78354bde2d2dd058085c28544bda1a7236fcf832 /kernel/sched | |
| parent | 6a0b19c0f39a7a7b7fb77d3867a733136ff059a3 (diff) | |
| download | linux-bf475ce0a3dd75b5d1df6c6c14ae25168caa15ac.tar.xz | |
sched/fair: Add per-CPU min capacity to sched_group_capacity
struct sched_group_capacity currently represents the compute capacity
sum of all CPUs in the sched_group.
Unless it is divided by the group_weight to get the average capacity
per CPU, it hides differences in CPU capacity for mixed capacity systems
(e.g. high RT/IRQ utilization or ARM big.LITTLE).
But even the average may not be sufficient if the group covers CPUs of
different capacities.
Instead, by extending struct sched_group_capacity to indicate min per-CPU
capacity in the group a suitable group for a given task utilization can
more easily be found such that CPUs with reduced capacity can be avoided
for tasks with high utilization (not implemented by this patch).
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: freedom.tan@mediatek.com
Cc: keita.kobayashi.ym@renesas.com
Cc: mgalbraith@suse.de
Cc: sgurrappadi@nvidia.com
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1476452472-24740-4-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/core.c | 3 | ||||
| -rw-r--r-- | kernel/sched/fair.c | 17 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 3 |
3 files changed, 16 insertions, 7 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f3cfa0dd5b34..6bf1fd3514d5 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5708,7 +5708,7 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, printk(KERN_CONT " %*pbl", cpumask_pr_args(sched_group_cpus(group))); if (group->sgc->capacity != SCHED_CAPACITY_SCALE) { - printk(KERN_CONT " (cpu_capacity = %d)", + printk(KERN_CONT " (cpu_capacity = %lu)", group->sgc->capacity); } @@ -6185,6 +6185,7 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu) * die on a /0 trap. */ sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); + sg->sgc->min_capacity = SCHED_CAPACITY_SCALE; /* * Make sure the first group of this domain contains the diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1ad37064c0c2..faf8f18616e6 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6909,13 +6909,14 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu) cpu_rq(cpu)->cpu_capacity = capacity; sdg->sgc->capacity = capacity; + sdg->sgc->min_capacity = capacity; } void update_group_capacity(struct sched_domain *sd, int cpu) { struct sched_domain *child = sd->child; struct sched_group *group, *sdg = sd->groups; - unsigned long capacity; + unsigned long capacity, min_capacity; unsigned long interval; interval = msecs_to_jiffies(sd->balance_interval); @@ -6928,6 +6929,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu) } capacity = 0; + min_capacity = ULONG_MAX; if (child->flags & SD_OVERLAP) { /* @@ -6952,11 +6954,12 @@ void update_group_capacity(struct sched_domain *sd, int cpu) */ if (unlikely(!rq->sd)) { capacity += capacity_of(cpu); - continue; + } else { + sgc = rq->sd->groups->sgc; + capacity += sgc->capacity; } - sgc = rq->sd->groups->sgc; - capacity += sgc->capacity; + min_capacity = min(capacity, min_capacity); } } else { /* @@ -6966,12 +6969,16 @@ void update_group_capacity(struct sched_domain *sd, int cpu) group = child->groups; do { - capacity += group->sgc->capacity; + struct sched_group_capacity *sgc = group->sgc; + + capacity += sgc->capacity; + min_capacity = min(sgc->min_capacity, min_capacity); group = group->next; } while (group != child->groups); } sdg->sgc->capacity = capacity; + sdg->sgc->min_capacity = min_capacity; } /* diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 055f935d4421..345c1ccaba34 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -892,7 +892,8 @@ struct sched_group_capacity { * CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity * for a single CPU. */ - unsigned int capacity; + unsigned long capacity; + unsigned long min_capacity; /* Min per-CPU capacity in group */ unsigned long next_update; int imbalance; /* XXX unrelated to capacity but shared group state */ |