linux-kernel - Re: [PATCH V6 1/3] cpuidle: play_idle: Make play

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Message-ID: <d185fdf8-8398-c8f5-b49a-47e5bb00607c@linaro.org>
Date:   Wed, 6 Nov 2019 19:27:47 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     rjw@...ysocki.net
Cc:     mathieu.poirier@...aro.org, mingo@...hat.com, peterz@...radead.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        ulf.hansson@...aro.org
Subject: Re: [PATCH V6 1/3] cpuidle: play_idle: Make play_idle more flexible


Hi Rafael,


On 30/10/2019 08:51, Daniel Lezcano wrote:
> The play_idle function has two users, the intel powerclamp and the
> idle_injection.
> 
> The idle injection cooling device uses the function via the
> idle_injection powercap's APIs. Unfortunately, play_idle is currently
> limited by the idle state depth: by default the deepest idle state is
> selected. On the ARM[64] platforms, most of the time it is the cluster
> idle state, the exit latency and the residency can be very high. That
> reduces the scope of the idle injection usage because the impact on
> the performances can be very significant.
> 
> If the idle injection cycles can be done with a shallow state like a
> retention state, the cooling effect would eventually give similar
> results than the cpufreq cooling device.
> 
> In order to prepare the function to receive an idle state parameter,
> let's replace the 'use_deepest_state' boolean field with 'use_state'
> and use this value to enter the specific idle state.
> 
> The current code keeps the default behavior which is go to the deepest
> idle state.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
> Acked-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>

Is it possible to merge this series so I can make some progress on
upstreaming the idle cooling device which depends on these three patches?

Thanks

  -- Daniel






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