From: Morten Rasmussen <morten.rasmussen@arm.com>
To: peterz@infradead.org, mingo@redhat.com
Cc: dietmar.eggemann@arm.com, yuyang.du@intel.com,
vincent.guittot@linaro.org, mgalbraith@suse.de,
sgurrappadi@nvidia.com, freedom.tan@mediatek.com,
keita.kobayashi.ym@renesas.com, linux-kernel@vger.kernel.org,
Morten Rasmussen <morten.rasmussen@arm.com>
Subject: [PATCH v3 12/13] sched: Add per-cpu min capacity to sched_group_capacity
Date: Mon, 25 Jul 2016 14:34:29 +0100 [thread overview]
Message-ID: <1469453670-2660-13-git-send-email-morten.rasmussen@arm.com> (raw)
In-Reply-To: <1469453670-2660-1-git-send-email-morten.rasmussen@arm.com>
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).
cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
---
kernel/sched/core.c | 3 ++-
kernel/sched/fair.c | 17 ++++++++++++-----
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 600f1296aa4c..745817970162 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5632,7 +5632,7 @@ 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);
}
@@ -6101,6 +6101,7 @@ 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 e3654409d099..f3019b85b6e3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6731,13 +6731,14 @@ 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);
@@ -6750,6 +6751,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
}
capacity = 0;
+ min_capacity = ULONG_MAX;
if (child->flags & SD_OVERLAP) {
/*
@@ -6774,11 +6776,12 @@ 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 {
/*
@@ -6788,12 +6791,16 @@ 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 444d8f38743f..75368a5eb836 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -869,7 +869,8 @@ 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 */
/*
--
1.9.1
next prev parent reply other threads:[~2016-07-25 13:35 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-25 13:34 [PATCH v3 00/13] sched: Clean-ups and asymmetric cpu capacity support Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 01/13] sched: Fix power to capacity renaming in comment Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 02/13] sched/fair: Consistent use of prev_cpu in wakeup path Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 03/13] sched/fair: Optimize find_idlest_cpu() when there is no choice Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 04/13] sched/core: Remove unnecessary null-pointer check Morten Rasmussen
2016-08-18 10:56 ` [tip:sched/core] sched/core: Remove unnecessary NULL-pointer check tip-bot for Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 05/13] sched: Introduce SD_ASYM_CPUCAPACITY sched_domain topology flag Morten Rasmussen
2016-08-15 10:54 ` Peter Zijlstra
2016-08-15 11:43 ` Morten Rasmussen
2016-08-18 10:56 ` [tip:sched/core] sched/core: Clarify SD_flags comment tip-bot for Peter Zijlstra
2016-08-17 8:42 ` [PATCH v3 05/13] sched: Introduce SD_ASYM_CPUCAPACITY sched_domain topology flag Wanpeng Li
2016-08-17 9:23 ` Morten Rasmussen
2016-08-17 9:26 ` Wanpeng Li
2016-08-18 10:56 ` [tip:sched/core] sched/core: " tip-bot for Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 06/13] sched/core: Pass child domain into sd_init Morten Rasmussen
2016-08-18 10:57 ` [tip:sched/core] sched/core: Pass child domain into sd_init() tip-bot for Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 07/13] sched: Enable SD_BALANCE_WAKE for asymmetric capacity systems Morten Rasmussen
2016-08-18 10:57 ` [tip:sched/core] sched/core: " tip-bot for Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 08/13] sched: Store maximum per-cpu capacity in root domain Morten Rasmussen
2016-08-01 18:53 ` Dietmar Eggemann
2016-08-16 12:24 ` Vincent Guittot
2016-08-18 10:58 ` [tip:sched/core] sched/core: Store maximum per-CPU " tip-bot for Dietmar Eggemann
2016-07-25 13:34 ` [PATCH v3 09/13] sched/fair: Let asymmetric cpu configurations balance at wake-up Morten Rasmussen
2016-08-15 13:39 ` Peter Zijlstra
2016-08-15 15:01 ` Morten Rasmussen
2016-08-15 15:10 ` Peter Zijlstra
2016-08-15 15:30 ` Morten Rasmussen
2016-08-18 10:58 ` [tip:sched/core] sched/fair: Let asymmetric CPU " tip-bot for Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 10/13] sched/fair: Compute task/cpu utilization at wake-up more correctly Morten Rasmussen
2016-08-15 14:23 ` Peter Zijlstra
2016-08-15 15:42 ` Morten Rasmussen
2016-08-18 8:40 ` Morten Rasmussen
2016-08-18 10:24 ` Morten Rasmussen
2016-08-18 11:46 ` Wanpeng Li
2016-08-18 13:45 ` Morten Rasmussen
2016-08-19 1:43 ` Wanpeng Li
2016-08-19 14:03 ` Morten Rasmussen
2016-08-22 1:48 ` Wanpeng Li
2016-08-22 11:29 ` Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 11/13] sched/fair: Consider spare capacity in find_idlest_group() Morten Rasmussen
2016-08-16 13:57 ` Vincent Guittot
2016-08-18 11:16 ` Morten Rasmussen
2016-08-18 12:28 ` Peter Zijlstra
2016-07-25 13:34 ` Morten Rasmussen [this message]
2016-07-25 13:34 ` [PATCH v3 13/13] sched/fair: Avoid pulling tasks from non-overloaded higher capacity groups Morten Rasmussen
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