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 [thread overview]
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.
next prev parent reply other threads:[~2020-08-31 7:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-21 14:00 [RFC PATCH v3 0/2] Add Krait Cache Scaling support 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
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