From: Shrikanth Hegde <sshegde@linux.ibm.com>
To: mingo@kernel.org, peterz@infradead.org,
vincent.guittot@linaro.org, linux-kernel@vger.kernel.org
Cc: sshegde@linux.ibm.com, kprateek.nayak@amd.com,
juri.lelli@redhat.com, vschneid@redhat.com, tglx@linutronix.de,
dietmar.eggemann@arm.com, anna-maria@linutronix.de,
frederic@kernel.org, wangyang.guo@intel.com
Subject: [PATCH v3 2/3] sched/fair: Change likelyhood of nohz.nr_cpus
Date: Wed, 7 Jan 2026 12:21:24 +0530 [thread overview]
Message-ID: <20260107065125.669668-3-sshegde@linux.ibm.com> (raw)
In-Reply-To: <20260107065125.669668-1-sshegde@linux.ibm.com>
These days most of the system have multi cores. The likelyhood of
at least one or more CPUs in nohz (idle state) is higher.
Give accurate hint to the branch predictor.
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
---
kernel/sched/fair.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 17e4e8ac5fca..c03f963f6216 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -12464,9 +12464,9 @@ static void nohz_balancer_kick(struct rq *rq)
/*
* None are in tickless mode and hence no need for NOHZ idle load
- * balancing:
+ * balancing
*/
- if (likely(!atomic_read(&nohz.nr_cpus)))
+ if (unlikely(!atomic_read(&nohz.nr_cpus)))
return;
if (rq->nr_running >= 2) {
--
2.47.3
next prev parent reply other threads:[~2026-01-07 6:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-07 6:51 [PATCH v3 0/3] sched/fair: Improve nohz fields for large systems Shrikanth Hegde
2026-01-07 6:51 ` [PATCH v3 1/3] sched/fair: Move checking for nohz cpus after time check Shrikanth Hegde
2026-01-08 12:44 ` Peter Zijlstra
2026-01-09 15:14 ` Shrikanth Hegde
2026-01-07 6:51 ` Shrikanth Hegde [this message]
2026-01-07 6:51 ` [PATCH v3 3/3] sched/fair: Remove nohz.nr_cpus and use weight of cpumask instead Shrikanth Hegde
2026-01-09 14:44 ` Valentin Schneider
2026-01-09 15:15 ` Shrikanth Hegde
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