LKML Archive on lore.kernel.org
 help / color / Atom feed
From: <ansuelsmth@gmail.com>
To: "'Sibi Sankar'" <sibis@codeaurora.org>,
	"'Viresh Kumar'" <viresh.kumar@linaro.org>
Cc: <vincent.guittot@linaro.org>, <saravanak@google.com>,
	"'Sudeep Holla'" <sudeep.holla@arm.com>,
	"'Rafael J. Wysocki'" <rjw@rjwysocki.net>,
	"'Rob Herring'" <robh+dt@kernel.org>, <linux-pm@vger.kernel.org>,
	<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: R: [RFC PATCH v3 0/2] Add Krait Cache Scaling support
Date: Mon, 31 Aug 2020 09:41:08 +0200
Message-ID: <039d01d67f6a$188700d0$49950270$@gmail.com> (raw)
In-Reply-To: <b339e01f9d1e955137120daa06d26228@codeaurora.org>



> -----Messaggio originale-----
> Da: sibis=codeaurora.org@mg.codeaurora.org
> <sibis=codeaurora.org@mg.codeaurora.org> Per conto di Sibi Sankar
> Inviato: lunedì 31 agosto 2020 07:46
> A: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: Ansuel Smith <ansuelsmth@gmail.com>; vincent.guittot@linaro.org;
> saravanak@google.com; Sudeep Holla <sudeep.holla@arm.com>; Rafael J.
> Wysocki <rjw@rjwysocki.net>; Rob Herring <robh+dt@kernel.org>; linux-
> pm@vger.kernel.org; devicetree@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Oggetto: Re: [RFC PATCH v3 0/2] Add Krait Cache Scaling support
> 
> On 2020-08-24 16:10, Viresh Kumar wrote:
> > +Vincent/Saravana/Sibi
> >
> > On 21-08-20, 16:00, Ansuel Smith wrote:
> >> This adds Krait Cache scaling support using the cpufreq notifier.
> >> I have some doubt about where this should be actually placed (clk or
> >> cpufreq)?
> >> Also the original idea was to create a dedicated cpufreq driver (like
> >> it's done in
> >> the codeaurora qcom repo) by copying the cpufreq-dt driver and adding
> >> the cache
> >> scaling logic but i still don't know what is better. Have a very
> >> similar driver or
> >> add a dedicated driver only for the cache using the cpufreq notifier
> >> and do the
> >> scale on every freq transition.
> >> Thanks to everyone who will review or answer these questions.
> >
> > Saravana was doing something with devfreq to solve such issues if I
> > wasn't mistaken.
> >
> > Sibi ?
> 
> IIRC the final plan was to create a devfreq device
> and devfreq-cpufreq based governor to scale them, this
> way one can switch to a different governor if required.

So in this case I should convert this patch to a devfreq driver- 
Isn't overkill to use a governor for such a task?
(3 range based on the cpufreq?)

> (I don't see if ^^ applies well for l2 though). In the
> interim until such a solution is acked on the list we
> just scale the resources directly from the cpufreq

In this case for this SoC we can't really scale the L2 freq
with the cpu since we observed a bug and we need to switch
back to the idle freq sometimes. Also this SoC use the generic
cpufreq-dt driver and doesn't have a dedicated driver. So we
must use a notifier.

> driver. On SDM845/SC7180 SoCs, L3 is modeled as a
> interconnect provider and is directly scaled from the
> cpufreq-hw driver.
> 
> --
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> a Linux Foundation Collaborative Project.


  reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-21 14:00 Ansuel Smith
2020-08-21 14:00 ` [RFC PATCH v3 1/2] cpufreq: qcom: " Ansuel Smith
2020-08-21 14:00 ` [RFC PATCH v3 2/2] dt-bindings: cpufreq: Document Krait CPU Cache scaling Ansuel Smith
2020-08-24 17:28   ` Rob Herring
2020-08-24 10:40 ` [RFC PATCH v3 0/2] Add Krait Cache Scaling support Viresh Kumar
2020-08-31  5:45   ` Sibi Sankar
2020-08-31  7:41     ` ansuelsmth [this message]
2020-09-03  6:53       ` R: " Viresh Kumar
2020-09-03  7:13         ` Sibi Sankar
2020-09-03 11:00           ` R: " ansuelsmth

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='039d01d67f6a$188700d0$49950270$@gmail.com' \
    --to=ansuelsmth@gmail.com \
    --cc=devicetree@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=rjw@rjwysocki.net \
    --cc=robh+dt@kernel.org \
    --cc=saravanak@google.com \
    --cc=sibis@codeaurora.org \
    --cc=sudeep.holla@arm.com \
    --cc=vincent.guittot@linaro.org \
    --cc=viresh.kumar@linaro.org \
    /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

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git