Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 19 Jun 2018 14:16:43 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Quentin Perret <quentin.perret@arm.com>
Cc:     rjw@rjwysocki.net, gregkh@linuxfoundation.org,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        mingo@redhat.com, dietmar.eggemann@arm.com,
        morten.rasmussen@arm.com, chris.redpath@arm.com,
        patrick.bellasi@arm.com, valentin.schneider@arm.com,
        vincent.guittot@linaro.org, thara.gopinath@linaro.org,
        viresh.kumar@linaro.org, tkjos@google.com, joelaf@google.com,
        smuckle@google.com, adharmap@quicinc.com, skannan@quicinc.com,
        pkondeti@codeaurora.org, juri.lelli@redhat.com,
        edubezval@gmail.com, srinivas.pandruvada@linux.intel.com,
        currojerez@riseup.net, javi.merino@kernel.org
Subject: Re: [RFC PATCH v3 04/10] PM / EM: Expose the Energy Model in sysfs
Message-ID: <20180619121643.GR2458@hirez.programming.kicks-ass.net>
References: <20180521142505.6522-1-quentin.perret@arm.com>
 <20180521142505.6522-5-quentin.perret@arm.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20180521142505.6522-5-quentin.perret@arm.com>
User-Agent: Mutt/1.10.0 (2018-05-17)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, May 21, 2018 at 03:24:59PM +0100, Quentin Perret wrote:
> This exposes the Energy Model (read-only) of all frequency domains in
> sysfs for convenience. To do so, a parent kobject is added to the CPU
> subsystem under the umbrella of which a kobject for each frequency
> domain is attached.
> 
> The resulting hierarchy is as follows for a platform with two frequency
> domains for example:
> 
>    /sys/devices/system/cpu/energy_model
>    ├── fd0
>    │   ├── capacity
>    │   ├── cpus
>    │   ├── frequency
>    │   └── power
>    └── fd4
>        ├── capacity
>        ├── cpus
>        ├── frequency
>        └── power
> 

Given that each FD can have multiple {freq,power} tuples and sysfs has a
one value per file policy, how does this work?