linux-kernel - Re: [PATCH RESEND v2 0/3] condition EAS enablement on FI support

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Date:   Wed, 18 Nov 2020 15:01:41 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Ionela Voinescu <ionela.voinescu@....com>
Cc:     mingo@...hat.com, vincent.guittot@...aro.org,
        catalin.marinas@....com, will@...nel.org, rjw@...ysocki.net,
        viresh.kumar@...aro.org, dietmar.eggemann@....com,
        qperret@...gle.com, valentin.schneider@....com,
        linux-pm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH RESEND v2 0/3] condition EAS enablement on FI support

On Wed, Nov 18, 2020 at 11:42:34AM +0000, Ionela Voinescu wrote:
> Hi guys,
> 
> On Tuesday 27 Oct 2020 at 18:07:10 (+0000), Ionela Voinescu wrote:
> > Given the maturity gained by cpufreq-based Frequency Invariance (FI)
> > support following the patches at [1], this series conditions Energy
> > Aware Scheduling (EAS) enablement on a frequency invariant system.
> > 
> > Currently, EAS can be enabled on a system without FI support, leading
> > to incorrect (energy-wise) task placements. As no warning is emitted,
> > it could take some debugging effort to track the behavior back to the
> > lack of FI support; this series changes that by disabling EAS
> > (and advertising it) when FI support is missing.
> > 
> > The series is structured as follows:
> >  - 1/3 - create function that can rebuild the scheduling and EAS'
> >    performance domains if EAS' initial conditions change
> >  - 2/3 - arm64: rebuild scheduling and performance domains in the
> >          case of late, counter-driven FI initialisation.
> >  - 3/3 - condition EAS enablement on FI support
> > 
> > RESEND v2: rebase and retest on v5.10-rc1
> > 
> 
> This still applies nicely on v5.10-rc4.
> 
> Peter, given that 1/3 and 2/3 are acked, do you think there's anything
> else that needs to be done for this?

I'll take it, thanks!