From: Marcelo Tosatti <mtosatti@redhat.com>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] sched/idle: disable tick in idle=poll idle entry
Date: Wed, 29 Oct 2025 15:01:50 -0300 [thread overview]
Message-ID: <aQJWjteaSaaC1dnU@tpad> (raw)
In-Reply-To: <aQJWWIDMMUxqDxnR@tpad>
On Wed, Oct 29, 2025 at 03:00:56PM -0300, Marcelo Tosatti wrote:
>
> 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.
>
> Change tick_nohz_full_kick_cpu to set NEED_RESCHED bit, to handle the
> case where a new timer is added from an interrupt. This breaks out of
> cpu_idle_poll and rearms the timer if necessary.
Frederic,
As a reminder, this is the original patch and discussion:
https://patchew.org/linux/ZIEqlkIASx2F2DRF@tpad/
next prev parent reply other threads:[~2025-10-29 18:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-29 18:00 [PATCH v2] sched/idle: disable tick in idle=poll idle entry Marcelo Tosatti
2025-10-29 18:01 ` Marcelo Tosatti [this message]
2025-10-30 16:06 ` Frederic Weisbecker
2025-11-03 11:30 ` Marcelo Tosatti
2025-12-10 13:32 ` Frederic Weisbecker
2025-11-01 19:30 ` Thomas Gleixner
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