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From: Peter Zijlstra <peterz@infradead.org>
To: leo.yan@linaro.org
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Linux PM <linux-pm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Frederic Weisbecker <frederic@kernel.org>
Subject: Re: [PATCH v5] cpuidle: menu: Handle stopped tick more aggressively
Date: Mon, 20 Aug 2018 13:04:10 +0200	[thread overview]
Message-ID: <20180820110410.GY2494@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180814154441.GA13920@leoy-ThinkPad-X240s>

On Tue, Aug 14, 2018 at 11:44:41PM +0800, leo.yan@linaro.org wrote:
> I agree this patch can resolve the issue you mentioned in the commit
> log, but this patch will be fragile for below case, so it will select
> state1 but not state2, how about you think for this case?
> 
> Idle_state0::
> target_residency   TICK_USEC   Prediction
>     |                 |       /
>     V                 V      /
> -----------------------------------------------------> Time length
>                                 ^                 ^
>                                 |                 |
>                             Idle_state1:       Idle_state2:
>                             target_residency   target_residency

If someone can demonstate this is an actual problem; then we need to fix
it I suppose. But it would be very good to have a real world
need/reproducer for it first.

  parent reply	other threads:[~2018-08-20 11:04 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-10  7:34 [PATCH] cpuidle: menu: Handle stopped tick more aggressively Rafael J. Wysocki
2018-08-10  7:57 ` [PATCH v2] " Rafael J. Wysocki
2018-08-10  9:20   ` leo.yan
2018-08-10 11:04     ` Rafael J. Wysocki
2018-08-10 12:31       ` leo.yan
2018-08-12 10:07         ` Rafael J. Wysocki
2018-08-12 13:44           ` leo.yan
2018-08-13  7:58             ` Rafael J. Wysocki
2018-08-10 11:15   ` [PATCH v3] " Rafael J. Wysocki
2018-08-12 14:55     ` leo.yan
2018-08-13  8:11       ` Rafael J. Wysocki
2018-08-20 10:15       ` Peter Zijlstra
2018-08-13 11:26     ` [PATCH v4] " Rafael J. Wysocki
2018-08-14 10:34       ` [PATCH v5] " Rafael J. Wysocki
2018-08-14 15:44         ` leo.yan
2018-08-14 17:26           ` Rafael J. Wysocki
2018-08-20 11:04           ` Peter Zijlstra [this message]
2018-08-20 11:02         ` Peter Zijlstra
2018-08-11 16:32 ` [PATCH] " kbuild test robot
2018-08-12 22:13 ` Dan Carpenter

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