From: Vincent Guittot <vincent.guittot@linaro.org>
To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
linux-kernel@vger.kernel.org, joel@joelfernandes.org,
valentin.schneider@arm.com
Cc: fweisbec@gmail.com, tglx@linutronix.de, qais.yousef@arm.com,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: [PATCH 4/7 v4] sched/fair: merge for each idle cpu loop of ILB
Date: Wed, 24 Feb 2021 14:30:04 +0100 [thread overview]
Message-ID: <20210224133007.28644-5-vincent.guittot@linaro.org> (raw)
In-Reply-To: <20210224133007.28644-1-vincent.guittot@linaro.org>
Remove the specific case for handling this_cpu outside for_each_cpu() loop
when running ILB. Instead we use for_each_cpu_wrap() and start with the
next cpu after this_cpu so we will continue to finish with this_cpu.
update_nohz_stats() is now used for this_cpu too and will prevents
unnecessary update. We don't need a special case for handling the update of
nohz.next_balance for this_cpu anymore because it is now handled by the
loop like others.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
kernel/sched/fair.c | 32 +++++++-------------------------
1 file changed, 7 insertions(+), 25 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f52f4dd3fb9e..0323fda07682 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -10043,22 +10043,9 @@ static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle)
* When the cpu is attached to null domain for ex, it will not be
* updated.
*/
- if (likely(update_next_balance)) {
+ if (likely(update_next_balance))
rq->next_balance = next_balance;
-#ifdef CONFIG_NO_HZ_COMMON
- /*
- * If this CPU has been elected to perform the nohz idle
- * balance. Other idle CPUs have already rebalanced with
- * nohz_idle_balance() and nohz.next_balance has been
- * updated accordingly. This CPU is now running the idle load
- * balance for itself and we need to update the
- * nohz.next_balance accordingly.
- */
- if ((idle == CPU_IDLE) && time_after(nohz.next_balance, rq->next_balance))
- nohz.next_balance = rq->next_balance;
-#endif
- }
}
static inline int on_null_domain(struct rq *rq)
@@ -10385,8 +10372,12 @@ static void _nohz_idle_balance(struct rq *this_rq, unsigned int flags,
*/
smp_mb();
- for_each_cpu(balance_cpu, nohz.idle_cpus_mask) {
- if (balance_cpu == this_cpu || !idle_cpu(balance_cpu))
+ /*
+ * Start with the next CPU after this_cpu so we will end with this_cpu and let a
+ * chance for other idle cpu to pull load.
+ */
+ for_each_cpu_wrap(balance_cpu, nohz.idle_cpus_mask, this_cpu+1) {
+ if (!idle_cpu(balance_cpu))
continue;
/*
@@ -10432,15 +10423,6 @@ static void _nohz_idle_balance(struct rq *this_rq, unsigned int flags,
if (likely(update_next_balance))
nohz.next_balance = next_balance;
- /* Newly idle CPU doesn't need an update */
- if (idle != CPU_NEWLY_IDLE) {
- update_blocked_averages(this_cpu);
- has_blocked_load |= this_rq->has_blocked_load;
- }
-
- if (flags & NOHZ_BALANCE_KICK)
- rebalance_domains(this_rq, CPU_IDLE);
-
WRITE_ONCE(nohz.next_blocked,
now + msecs_to_jiffies(LOAD_AVG_PERIOD));
--
2.17.1
next prev parent reply other threads:[~2021-02-24 14:51 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-24 13:30 [PATCH 0/7 v4] move update blocked load outside newidle_balance Vincent Guittot
2021-02-24 13:30 ` [PATCH 1/7 v4] sched/fair: remove update of blocked load from newidle_balance Vincent Guittot
2021-03-02 9:01 ` [tip: sched/core] sched/fair: Remove " tip-bot2 for Vincent Guittot
2021-03-03 9:49 ` tip-bot2 for Vincent Guittot
2021-03-06 11:42 ` tip-bot2 for Vincent Guittot
2021-02-24 13:30 ` [PATCH 2/7 v4] sched/fair: remove unused return of _nohz_idle_balance Vincent Guittot
2021-03-02 9:01 ` [tip: sched/core] sched/fair: Remove " tip-bot2 for Vincent Guittot
2021-03-03 9:49 ` tip-bot2 for Vincent Guittot
2021-03-06 11:42 ` tip-bot2 for Vincent Guittot
2021-02-24 13:30 ` [PATCH 3/7 v4] sched/fair: remove unused parameter of update_nohz_stats Vincent Guittot
2021-03-02 9:01 ` [tip: sched/core] sched/fair: Remove " tip-bot2 for Vincent Guittot
2021-03-03 9:49 ` tip-bot2 for Vincent Guittot
2021-03-05 13:55 ` [PATCH 3/7 v4] sched/fair: remove " Qais Yousef
2021-03-06 11:42 ` [tip: sched/core] sched/fair: Remove " tip-bot2 for Vincent Guittot
2021-02-24 13:30 ` Vincent Guittot [this message]
2021-03-02 9:01 ` [tip: sched/core] sched/fair: Merge for each idle cpu loop of ILB tip-bot2 for Vincent Guittot
2021-03-03 9:49 ` tip-bot2 for Vincent Guittot
2021-03-06 11:42 ` tip-bot2 for Vincent Guittot
2021-02-24 13:30 ` [PATCH 5/7 v4] sched/fair: reorder newidle_balance pulled_task tests Vincent Guittot
2021-03-02 9:01 ` [tip: sched/core] sched/fair: Reorder " tip-bot2 for Vincent Guittot
2021-03-03 9:49 ` tip-bot2 for Vincent Guittot
2021-03-06 11:42 ` tip-bot2 for Vincent Guittot
2021-02-24 13:30 ` [PATCH 6/7 v4] sched/fair: trigger the update of blocked load on newly idle cpu Vincent Guittot
2021-03-02 9:01 ` [tip: sched/core] sched/fair: Trigger " tip-bot2 for Vincent Guittot
2021-03-03 9:49 ` tip-bot2 for Vincent Guittot
2021-03-05 13:52 ` [PATCH 6/7 v4] sched/fair: trigger " Qais Yousef
2021-03-06 11:42 ` [tip: sched/core] sched/fair: Trigger " tip-bot2 for Vincent Guittot
2021-02-24 13:30 ` [PATCH 7/7 v4] sched/fair: reduce the window for duplicated update Vincent Guittot
2021-03-02 9:01 ` [tip: sched/core] sched/fair: Reduce " tip-bot2 for Vincent Guittot
2021-03-03 9:49 ` tip-bot2 for Vincent Guittot
2021-03-06 11:42 ` tip-bot2 for Vincent Guittot
2021-02-24 15:53 ` [PATCH 0/7 v4] move update blocked load outside newidle_balance Peter Zijlstra
2021-02-24 15:57 ` Vincent Guittot
2021-02-24 17:41 ` Peter Zijlstra
2021-02-24 17:51 ` Vincent Guittot
2021-02-24 18:17 ` Peter Zijlstra
2021-02-24 18:46 ` Valentin Schneider
2021-02-25 8:05 ` Vincent Guittot
2021-02-25 12:14 ` Valentin Schneider
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