linux-kernel - Re: [PATCH 0/6] arm, arm64: frequency- and cpu-invariant accounting support for task scheduler

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Date:   Mon, 12 Jun 2017 14:04:16 +0100
From:   Juri Lelli <juri.lelli@....com>
To:     Dietmar Eggemann <dietmar.eggemann@....com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux@....linux.org.uk, linux-arm-kernel@...ts.infradead.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Russell King <rmk+kernel@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Morten Rasmussen <morten.rasmussen@....com>
Subject: Re: [PATCH 0/6] arm, arm64: frequency- and cpu-invariant accounting
 support for task scheduler

This time hopefully fixing Vincent's email address..

On 12/06/17 14:00, Juri Lelli wrote:
> Hi Dietmar,
> 
> On 08/06/17 08:55, Dietmar Eggemann wrote:
> > For a more accurate (i.e. frequency- and cpu-invariant) load-tracking
> > the task scheduler needs a frequency-scaling and on a heterogeneous
> > system a cpu-scaling correction factor.
> > 
> > This patch-set implements a Frequency Invariance Engine (FIE)
> > (topology_get_freq_scale()) in drivers/base/arch_topology.c to provide
> > a frequency-scaling correction factor.
> > 
> > The Cpu Invariance Engine (CIE) (topology_get_cpu_scale()) providing a
> > cpu-scaling correction factor was already introduced by the "Fix issues
> > and factorize arm/arm64 capacity information code" patch-set [1].
> > 
> > This patch-set also enables the frequency- and cpu-invariant accounting
> > support. Enabling here means to associate (wire) the task scheduler
> > cname arch_scale_freq_capacity and arch_scale_cpu_capacity with the FIE
> > and CIE function names from drivers/base/arch_topology.c. This replaces
> > the task scheduler's default FIE and CIE in kernel/sched/sched.h.
> > 
> > Patch high level description:
> > 
> >  [   01/06] Rework cpufreq policy notifier for frequency-invariant
> >             accounting support
> >  [   02/06] Frequency Invariance Engine (FIE)
> >  [03,04/06] Enable frequency- and cpu-invariant accounting support on
> >             arm
> >  [05,06/06] Enable frequency- and cpu-invariant accounting support on
> >             arm64
> > 
> > The patch-set is based on top of linux-next/master (tag: next-20170607)
> > and it is also available from:
> > 
> >  git://linux-arm.org/linux-de.git upstream/freq_and_cpu_inv
> > 
> > It has been tested on TC2 (arm) and JUNO (arm64) by running a ramp-up
> > rt-app task pinned to a cpu with the ondemand cpufreq governor and
> > checking the load-tracking signals of this task.
> > 
> 
> The whole set looks OK to me, and I tested it as well.
> 
> Feel free to add my
> 
> Reviewed-and-tested-by: Juri Lelli <juri.lelli@....com>
> 
> to it.
> 
> Best,
> 
> - Juri