From: Vincent Guittot <vincent.guittot@linaro.org>
To: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org
Cc: valentin.schneider@arm.com, Morten.Rasmussen@arm.com,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: [RESEND PATCH 3/3] sched/fair: fix unnecessary increase of balance interval
Date: Tue, 2 Oct 2018 09:26:39 +0200 [thread overview]
Message-ID: <1538465199-20176-4-git-send-email-vincent.guittot@linaro.org> (raw)
In-Reply-To: <1538465199-20176-1-git-send-email-vincent.guittot@linaro.org>
In case of active balance, we increase the balance interval to cover
pinned tasks cases not covered by all_pinned logic. Neverthless, the active
migration triggered by asym packing should be treated as the normal
unbalanced case and reset the interval to default value otherwise active
migration for asym_packing can be easily delayed for hundreds of ms
because of this all_pinned detection mecanism.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
kernel/sched/fair.c | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 00f2171..4b6a226 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8456,22 +8456,32 @@ static struct rq *find_busiest_queue(struct lb_env *env,
*/
#define MAX_PINNED_INTERVAL 512
-static int need_active_balance(struct lb_env *env)
+static inline bool
+asym_active_balance(enum cpu_idle_type idle, unsigned int flags, int dst, int src)
{
- struct sched_domain *sd = env->sd;
-
- if (env->idle != CPU_NOT_IDLE) {
+ if (idle != CPU_NOT_IDLE) {
/*
* ASYM_PACKING needs to force migrate tasks from busy but
* lower priority CPUs in order to pack all tasks in the
* highest priority CPUs.
*/
- if ((sd->flags & SD_ASYM_PACKING) &&
- sched_asym_prefer(env->dst_cpu, env->src_cpu))
- return 1;
+ if ((flags & SD_ASYM_PACKING) &&
+ sched_asym_prefer(dst, src))
+ return true;
}
+ return false;
+}
+
+static int need_active_balance(struct lb_env *env)
+{
+ struct sched_domain *sd = env->sd;
+
+
+ if (asym_active_balance(env->idle, sd->flags, env->dst_cpu, env->src_cpu))
+ return 1;
+
/*
* The dst_cpu is idle and the src_cpu CPU has only 1 CFS task.
* It's worth migrating the task if the src_cpu's capacity is reduced
@@ -8749,7 +8759,8 @@ static int load_balance(int this_cpu, struct rq *this_rq,
} else
sd->nr_balance_failed = 0;
- if (likely(!active_balance)) {
+ if (likely(!active_balance) ||
+ asym_active_balance(env.idle, sd->flags, env.dst_cpu, env.src_cpu)) {
/* We were unbalanced, so reset the balancing interval */
sd->balance_interval = sd->min_interval;
} else {
--
2.7.4
prev parent reply other threads:[~2018-10-02 7:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-02 7:26 [RESEND PATCH 0/3] sched/fair: some fixes for asym_packing Vincent Guittot
2018-10-02 7:26 ` [RESEND PATCH 1/3] sched/fair: fix rounding issue for asym packing Vincent Guittot
2018-10-02 7:26 ` [RESEND PATCH 2/3] sched/fair: trigger asym_packing during idle load balance Vincent Guittot
2018-10-02 7:26 ` Vincent Guittot [this message]
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