From: Christian Loehle <christian.loehle@arm.com>
To: "Joel Fernandes (Google)" <joel@joelfernandes.org>,
linux-kernel@vger.kernel.org,
Anna-Maria Behnsen <anna-maria@linutronix.de>,
Frederic Weisbecker <frederic@kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC 2/3] tick-sched: Keep tick on if hrtimer is due imminently
Date: Mon, 11 Nov 2024 12:37:56 +0000 [thread overview]
Message-ID: <a491e879-364c-4b57-aa69-28608d8af4f0@arm.com> (raw)
In-Reply-To: <20241108174839.1016424-3-joel@joelfernandes.org>
On 11/8/24 17:48, Joel Fernandes (Google) wrote:
> In highres mode, the kernel only considers timer wheel events when
> considering whether to keep the tick on (via get_next_interrupt()).
>
> This seems odd because it consider several other reasons to keep the
> tick on. Further, turning off the tick does not help because once idle
> exit happens due to that imminent hrtimer interrupt, the tick hrtimer
> interrupt is requeued. That means more hrtimer rbtree operations for not
> much benefit.
>
> Ideally we should not have to do anything because the cpuidle governor
> should not try to the stop the tick because it knows about this
> situation, but apparently it still does try to stop the tick.
Any details on this? Which governor?
next prev parent reply other threads:[~2024-11-11 12:38 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-08 17:48 [RFC 0/3] tick-sched cleanups Joel Fernandes (Google)
2024-11-08 17:48 ` [RFC 1/3] tick-sched: Remove last_tick and calculate next tick from now Joel Fernandes (Google)
2024-11-11 23:43 ` Frederic Weisbecker
2024-11-12 13:46 ` Thomas Gleixner
2024-11-12 13:56 ` Frederic Weisbecker
2024-11-12 18:20 ` Joel Fernandes
2024-11-12 18:33 ` Joel Fernandes
2024-11-13 12:40 ` Frederic Weisbecker
2024-11-13 21:40 ` Joel Fernandes
2024-11-08 17:48 ` [RFC 2/3] tick-sched: Keep tick on if hrtimer is due imminently Joel Fernandes (Google)
2024-11-11 12:37 ` Christian Loehle [this message]
2024-11-11 15:56 ` Joel Fernandes
2024-11-11 16:55 ` Christian Loehle
2024-11-11 17:17 ` Joel Fernandes
2024-11-08 17:48 ` [RFC 3/3] tick-sched: Replace jiffie readout with idle_entrytime Joel Fernandes (Google)
2024-11-10 22:55 ` Joel Fernandes
2024-11-12 14:48 ` Thomas Gleixner
2024-11-13 21:46 ` Joel Fernandes
2024-11-11 22:25 ` Frederic Weisbecker
2024-11-13 22:39 ` Joel Fernandes
2024-11-12 14:30 ` Thomas Gleixner
2024-11-13 22:18 ` Joel Fernandes
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