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From: Yun Levi <ppbuk5246@gmail.com>
Date: Thu, 16 May 2024 17:12:33 +0100
Message-ID: <CAM7-yPRjjCS7VDz5-X4Z5gBCymoCMxGc+okL7+2WZiHM7D0C_w@mail.gmail.com>
Subject: Re: [PATCH v4] time/tick-sched: idle load balancing when nohz_full
 cpu becomes idle.
To: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>, Joel Fernandes <joel@joelfernandes.org>, 
	Vineeth Pillai <vineeth@bitbyteword.org>, Vincent Guittot <vincent.guittot@linaro.org>, 
	Dietmar Eggemann <dietmar.eggemann@arm.com>, anna-maria@linutronix.de, mingo@kernel.org, 
	tglx@linutronix.de, Markus.Elfring@web.de, linux-kernel@vger.kernel.org
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> > Yes, but stronger, as long as the CPU is part of a load-balance domain,
> > it must not disable the tick while running anything.
> >
> > that is, NOHZ_FULL must not become active unless it's running on a
> > single CPU partition.
>
> I like the idea but I'm afraid to introduce regressions while doing so,
> with people currently using nohz_full without proper partionning...

But I wonder when nohz_full cpu enters *idle".

If the cpuidle governor selects an idle state which wants "stop_tick",
If nohz_full cpu is still in sched domain, should it disable tick or not?