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 v4 2/3] sched/fair: Change likelyhood of nohz.nr_cpus
Date: Mon, 12 Jan 2026 10:34:41 +0530 [thread overview]
Message-ID: <20260112050442.138446-3-sshegde@linux.ibm.com> (raw)
In-Reply-To: <20260112050442.138446-1-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:[~2026-01-12 5:05 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-12 5:04 [PATCH v4 0/3] sched/fair: Improve nohz fields for large systems Shrikanth Hegde
2026-01-12 5:04 ` [PATCH v4 1/3] sched/fair: Move checking for nohz cpus after time check Shrikanth Hegde
2026-01-13 9:07 ` Vincent Guittot
2026-01-13 9:23 ` Shrikanth Hegde
2026-01-13 10:21 ` Vincent Guittot
2026-01-13 11:18 ` Shrikanth Hegde
2026-01-13 13:20 ` Vincent Guittot
2026-01-12 5:04 ` Shrikanth Hegde [this message]
2026-01-12 5:04 ` [PATCH v4 3/3] sched/fair: Remove nohz.nr_cpus and use weight of cpumask instead Shrikanth Hegde
2026-01-12 11:49 ` Valentin Schneider
2026-01-13 9:23 ` Vincent Guittot
2026-01-13 9:30 ` Shrikanth Hegde
2026-01-13 6:45 ` [PATCH v4 0/3] sched/fair: Improve nohz fields for large systems K Prateek Nayak
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260112050442.138446-3-sshegde@linux.ibm.com \
--to=sshegde@linux.ibm.com \
--cc=anna-maria@linutronix.de \
--cc=dietmar.eggemann@arm.com \
--cc=frederic@kernel.org \
--cc=juri.lelli@redhat.com \
--cc=kprateek.nayak@amd.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@kernel.org \
--cc=vincent.guittot@linaro.org \
--cc=vschneid@redhat.com \
--cc=wangyang.guo@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®