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Subject: Re: [PATCH 2/3] PM: EM: Make em_cpu_energy() able to return bigger
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To:     Peter Zijlstra <peterz@infradead.org>
Cc:     linux-kernel@vger.kernel.org, Chris.Redpath@arm.com,
        dietmar.eggemann@arm.com, morten.rasmussen@arm.com,
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        CCj.Yeh@mediatek.com
References: <20210625152603.25960-1-lukasz.luba@arm.com>
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From:   Lukasz Luba <lukasz.luba@arm.com>
Message-ID: <c7603e2f-5830-0731-cc2c-e42d5f6283be@arm.com>
Date:   Wed, 7 Jul 2021 11:23:51 +0100
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On 7/7/21 11:01 AM, Peter Zijlstra wrote:
> On Wed, Jul 07, 2021 at 09:09:08AM +0100, Lukasz Luba wrote:
>> For now we would live with this simple code which improves
>> all recent 64bit platforms and is easy to take it into Android
>> common kernel. The next step would be more scattered across
>> other subsystems, so harder to backport to Android 5.4 and others.
> 
> Ah, you *do* only care about 64bit :-) So one option is to only increase
> precision for 64BIT builds, just like we do for scale_load() and
> friends.
> 

Your suggestion is potentially a good compromise :-)
We could leave the 32bit alone and they would have old code and
precision.

Thank you for the comments. Let me discuss this internally with my team.