linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: Viresh Kumar <viresh.kumar@linaro.org>
To: Nicola Mazzucato <nicola.mazzucato@arm.com>
Cc: devicetree@vger.kernel.org, linux-pm@vger.kernel.org,
	vireshk@kernel.org, daniel.lezcano@linaro.org, rjw@rjwysocki.net,
	linux-kernel@vger.kernel.org, robh+dt@kernel.org,
	sudeep.holla@arm.com, chris.redpath@arm.com,
	Ionela Voinescu <ionela.voinescu@arm.com>,
	morten.rasmussen@arm.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 2/2] [RFC] CPUFreq: Add support for cpu-perf-dependencies
Date: Fri, 9 Oct 2020 16:47:11 +0530	[thread overview]
Message-ID: <20201009111711.5sl7m24engcwiqii@vireshk-i7> (raw)
In-Reply-To: <42e3c8e9-cadc-d013-1e1f-fa06af4a45ff@arm.com>

On 09-10-20, 12:10, Nicola Mazzucato wrote:
> I thought about it and looked for other platforms' DT to see if can reuse
> existing opp information. Unfortunately I don't think it is optimal. The reason
> being that, because cpus have the same opp table it does not necessarily mean
> that they share a clock wire. It just tells us that they have the same
> capabilities (literally just tells us they have the same V/f op points).

No.

> Unless I am missing something?

Yes.

Here are the different scenarios which can happen.
- Two CPUs have separate OPP tables, even if they are exact copy of
  each other, these CPUs don't share a clock line, but just v/f points
  as you said.

- Two CPUs use the same OPP table, i.e. both point to it, but
  "opp-shared" property is missing. This is same as above case. They
  just share the v/f points and this is the preferred way instead of
  duplicate OPP tables.

- Case two with "opp-shared" property present in the OPP table. The
  CPUs share clock-lines.

And this is exactly how we find out today if CPUs share a policy or
not.

-- 
viresh

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-10-09 11:18 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-24  9:53 [PATCH v2 0/2] CPUFreq: Add support for cpu performance dependencies Nicola Mazzucato
2020-09-24  9:53 ` [PATCH v2 1/2] dt-bindings: arm: Add devicetree binding for cpu-performance-dependencies Nicola Mazzucato
2020-10-08 13:42   ` Ionela Voinescu
2020-09-24  9:53 ` [PATCH v2 2/2] [RFC] CPUFreq: Add support for cpu-perf-dependencies Nicola Mazzucato
2020-10-06  7:19   ` Viresh Kumar
2020-10-07 12:58     ` Nicola Mazzucato
2020-10-08 11:02       ` Viresh Kumar
2020-10-08 15:03         ` Ionela Voinescu
2020-10-08 15:57           ` Rafael J. Wysocki
2020-10-08 17:08             ` Ionela Voinescu
2020-10-12 16:06             ` Sudeep Holla
2020-10-08 16:00           ` Nicola Mazzucato
2020-10-09  5:39             ` Viresh Kumar
2020-10-09 11:10               ` Nicola Mazzucato
2020-10-09 11:17                 ` Viresh Kumar [this message]
2020-10-09 14:01                 ` Rob Herring
2020-10-09 15:28                   ` Nicola Mazzucato
2020-10-12  4:19                     ` Viresh Kumar
2020-10-12 10:22                   ` Lukasz Luba
2020-10-12 10:50                     ` Rafael J. Wysocki
2020-10-12 11:05                       ` Lukasz Luba
2020-10-12 10:59                     ` Ionela Voinescu
2020-10-12 13:48                       ` Lukasz Luba
2020-10-12 16:30                         ` Ionela Voinescu
2020-10-12 18:19                           ` Lukasz Luba
2020-10-12 22:01                             ` Ionela Voinescu
2020-10-13 11:53                               ` Rafael J. Wysocki
2020-10-13 12:39                                 ` Ionela Voinescu
2020-10-15 15:56                                   ` Rafael J. Wysocki
2020-10-15 18:38                                     ` Ionela Voinescu
2020-10-12 13:59                     ` Rob Herring
2020-10-12 16:02                     ` Sudeep Holla
2020-10-12 15:54                   ` Sudeep Holla
2020-10-12 15:49               ` Sudeep Holla
2020-10-12 16:52                 ` Ionela Voinescu
2020-10-12 17:18                   ` Lukasz Luba
2020-10-14  4:25                     ` Viresh Kumar
2020-10-14  9:11                       ` Lukasz Luba
2020-10-19  8:50                       ` Nicola Mazzucato
2020-10-19  9:46                         ` Viresh Kumar
2020-10-19 13:36                           ` Nicola Mazzucato
2020-10-20 10:48                             ` Viresh Kumar
2020-10-13 13:53               ` Lukasz Luba
2020-10-14  4:20                 ` Viresh Kumar

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201009111711.5sl7m24engcwiqii@vireshk-i7 \
    --to=viresh.kumar@linaro.org \
    --cc=chris.redpath@arm.com \
    --cc=daniel.lezcano@linaro.org \
    --cc=devicetree@vger.kernel.org \
    --cc=ionela.voinescu@arm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=morten.rasmussen@arm.com \
    --cc=nicola.mazzucato@arm.com \
    --cc=rjw@rjwysocki.net \
    --cc=robh+dt@kernel.org \
    --cc=sudeep.holla@arm.com \
    --cc=vireshk@kernel.org \
    --subject='Re: [PATCH v2 2/2] [RFC] CPUFreq: Add support for cpu-perf-dependencies' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).