linux-kernel - Re: [PATCH 3/3] cpuidle/drivers/mbed: Add new governor for embedded systems

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Date:   Tue, 2 Apr 2019 18:02:02 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Quentin Perret <quentin.perret@....com>
Cc:     rjw@...ysocki.net, tglx@...utronix.de, ulf.hansson@...aro.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] cpuidle/drivers/mbed: Add new governor for embedded
 systems

On 02/04/2019 15:22, Quentin Perret wrote:
> Hi Daniel,
> 
> On Friday 08 Mar 2019 at 22:20:47 (+0100), Daniel Lezcano wrote:
>> Despite the naive idle state selection for this first iteration, the
>> governor provides a performance improvement of 30% for Jankbench
>> throughout for the same amount of energy than the menu governor
> 
> Wow, that sounds really good. Which kernel and board did you use for
> testing ? What's the perf. metric here ? The 99% percentile of frame
> completion time ?

Hi Quentin,

I tried on a hikey960 with an android kernel 4.19.

The used percentile is the 95%, the tests are jankbench list_view and
edit_text, and exoplayer. Values are normalized against the menu governor:

list_view:
 frame duration -35%
 count: +20%
 energy: +1%

edit text:
 frame duration -45%
 count: +27%
 energy: -0.3%

For audio and video playback, there is no frame drop.

audio
 - energy: -2.8%

video
 - energy: -3.8%

These are preliminary results.

  -- Daniel

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