linux-kernel - [PATCH v3 2/3] sched/fair: Change likelyhood of nohz.nr

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Message-ID: <20260107065125.669668-3-sshegde@linux.ibm.com>
Date: Wed,  7 Jan 2026 12:21:24 +0530
From: Shrikanth Hegde <sshegde@...ux.ibm.com>
To: mingo@...nel.org, peterz@...radead.org, vincent.guittot@...aro.org,
        linux-kernel@...r.kernel.org
Cc: sshegde@...ux.ibm.com, kprateek.nayak@....com, juri.lelli@...hat.com,
        vschneid@...hat.com, tglx@...utronix.de, dietmar.eggemann@....com,
        anna-maria@...utronix.de, frederic@...nel.org, wangyang.guo@...el.com
Subject: [PATCH v3 2/3] sched/fair: Change likelyhood of nohz.nr_cpus

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@...ux.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