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@kernel.org,
dietmar.eggemann@arm.com, anna-maria@linutronix.de,
frederic@kernel.org, wangyang.guo@intel.com
Subject: [PATCH v5 2/3] sched/fair: Change likelyhood of nohz.nr_cpus
Date: Thu, 15 Jan 2026 13:05:23 +0530 [thread overview]
Message-ID: <20260115073524.376643-3-sshegde@linux.ibm.com> (raw)
In-Reply-To: <20260115073524.376643-1-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.
Reviewed-and-tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
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 a4910658c5d6..3d843d1396ec 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -12463,9 +12463,9 @@ 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) {
--
2.51.0
next prev parent reply other threads:[~2026-01-15 7:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-15 7:35 [PATCH v5 0/3] sched/fair: Improve nohz fields for large systems Shrikanth Hegde
2026-01-15 7:35 ` [PATCH v5 1/3] sched/fair: Move checking for nohz cpus after time check Shrikanth Hegde
2026-01-15 21:44 ` [tip: sched/core] " tip-bot2 for Shrikanth Hegde
2026-01-15 7:35 ` Shrikanth Hegde [this message]
2026-01-15 21:44 ` [tip: sched/core] sched/fair: Change likelyhood of nohz.nr_cpus tip-bot2 for Shrikanth Hegde
2026-01-15 7:35 ` [PATCH v5 3/3] sched/fair: Remove nohz.nr_cpus and use weight of cpumask instead Shrikanth Hegde
2026-01-15 21:44 ` [tip: sched/core] " tip-bot2 for Shrikanth Hegde
2026-01-15 13:37 ` [PATCH v5 0/3] sched/fair: Improve nohz fields for large systems Vincent Guittot
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