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Subject: Re: [PATCH 1/3] sched/fair: Prepare variables for increased precision
 of EAS estimated energy
To:     Vincent Guittot <vincent.guittot@linaro.org>
Cc:     linux-kernel <linux-kernel@vger.kernel.org>,
        Chris Redpath <Chris.Redpath@arm.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Morten Rasmussen <morten.rasmussen@arm.com>,
        Quentin Perret <qperret@google.com>,
        "open list:THERMAL" <linux-pm@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>, segall@google.com,
        Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        CCj.Yeh@mediatek.com
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From:   Lukasz Luba <lukasz.luba@arm.com>
Message-ID: <58cb7ad3-ffff-8940-4c8e-2c46dcc86d54@arm.com>
Date:   Wed, 7 Jul 2021 11:41:16 +0100
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On 7/7/21 11:32 AM, Vincent Guittot wrote:
> On Wed, 7 Jul 2021 at 12:29, Lukasz Luba <lukasz.luba@arm.com> wrote:
>>
>>
>>
>> On 7/7/21 11:11 AM, Vincent Guittot wrote:
>>> On Wed, 7 Jul 2021 at 12:06, Lukasz Luba <lukasz.luba@arm.com> wrote:
>>>>
>>
>> [snip]
>>
>>>> No. It's in 0.1uW scale, so 800Watts. Which is 16 CPUs * 64Watts
>>>
>>> Oh! you want 0.1uW precision .... This doesn't seem realistic at all.
>>> I'm not even sure that the power model can even reach an accuracy of
>>> 1mW
>>>
>>
>> True, the EM is registering platform with 1mW precision, but 1uW
> 
> Do you mean 1uW or 0.1uW ?

In this patch set I've proposed 0.1uW, but I'm open to drop one
order of magnitude. The 1uW still be good.