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Date:   Tue, 14 Apr 2020 13:45:03 +0100
From:   Quentin Perret <qperret@google.com>
To:     Vincent Guittot <vincent.guittot@linaro.org>
Cc:     Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Luca Abeni <luca.abeni@santannapisa.it>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Wei Wang <wvw@google.com>,
        Alessio Balsini <balsini@google.com>,
        Pavan Kondeti <pkondeti@codeaurora.org>,
        Patrick Bellasi <patrick.bellasi@matbug.net>,
        Morten Rasmussen <morten.rasmussen@arm.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Qais Yousef <qais.yousef@arm.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] sched/topology: Store root domain CPU capacity sum
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On Wednesday 08 Apr 2020 at 19:03:57 (+0200), Vincent Guittot wrote:
> Or we can do the opposite and only use capacity_orig_of()/rq->cpu_capacity_orig.
> 
> Is there a case where the max cpu capacity changes over time ? So I
> would prefer to use cpu_capacity_orig which is a field of scheduler
> instead of always calling an external arch specific function

Note however that using arch_scale_cpu_capacity() would be more
efficient, especially on non-arm/arm64 systems where it is a
compile-time constant.

It's probably a matter of personal taste, but I find rq->cpu_capacity_orig
superfluous. It wastes space without actually giving you anything no?
Anybody remembers why it was introduced in the first place?

Thanks,
Quentin