From: Marcelo Tosatti <mtosatti@redhat.com>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: [PATCH] sched/idle: disable tick in idle=poll idle entry
Date: Wed, 7 Jun 2023 22:10:46 -0300 [thread overview]
Message-ID: <ZIEqlkIASx2F2DRF@tpad> (raw)
Commit a5183862e76fdc25f36b39c2489b816a5c66e2e5
("tick/nohz: Conditionally restart tick on idle exit") allows
a nohz_full CPU to enter idle and return from it with the
scheduler tick disabled (since the tick might be undesired noise).
The idle=poll case still unconditionally restarts the tick when entering
idle.
To reduce the noise for that case as well, stop the tick when entering
idle, for the idle=poll case.
tick_nohz_idle_exit (called if the NEED_RESCHED bit is set)
is responsible for re-enabling the tick when necessary.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 342f58a329f5..fdc240988ea9 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -276,7 +276,7 @@ static void do_idle(void)
* idle as we know that the IPI is going to arrive right away.
*/
if (cpu_idle_force_poll || tick_check_broadcast_expired()) {
- tick_nohz_idle_restart_tick();
+ tick_nohz_idle_stop_tick();
cpu_idle_poll();
} else {
cpuidle_idle_call();
next reply other threads:[~2023-06-08 1:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-08 1:10 Marcelo Tosatti [this message]
2023-06-08 8:34 ` [PATCH] sched/idle: disable tick in idle=poll idle entry Peter Zijlstra
2023-06-09 13:54 ` Marcelo Tosatti
2023-06-08 13:25 ` Frederic Weisbecker
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