linux-kernel - [tip: sched/core] sched/fair: Change likelyhood of nohz.nr

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Message-ID: <176851345658.510.10023012687723072941.tip-bot2@tip-bot2>
Date: Thu, 15 Jan 2026 21:44:16 -0000
From: "tip-bot2 for Shrikanth Hegde" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Shrikanth Hegde <sshegde@...ux.ibm.com>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>,
 Vincent Guittot <vincent.guittot@...aro.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: sched/core] sched/fair: Change likelyhood of nohz.nr_cpus

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     94e70734b4d034b9df795bd1ad3452ea96e742ca
Gitweb:        https://git.kernel.org/tip/94e70734b4d034b9df795bd1ad3452ea96e742ca
Author:        Shrikanth Hegde <sshegde@...ux.ibm.com>
AuthorDate:    Thu, 15 Jan 2026 13:05:23 +05:30
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Thu, 15 Jan 2026 22:41:27 +01:00

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.

Reviewed-and-tested-by: K Prateek Nayak <kprateek.nayak@....com>
Signed-off-by: Shrikanth Hegde <sshegde@...ux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@...aro.org>
Link: https://patch.msgid.link/20260115073524.376643-3-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 9afe0c6..4ae06ce 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -12459,9 +12459,9 @@ 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) {