> -----Messaggio originale----- > Da: sibis=codeaurora.org@xxxxxxxxxxxxxxxxx > <sibis=codeaurora.org@xxxxxxxxxxxxxxxxx> Per conto di Sibi Sankar > Inviato: giovedì 3 settembre 2020 09:13 > A: Viresh Kumar <viresh.kumar@xxxxxxxxxx> > Cc: ansuelsmth@xxxxxxxxx; vincent.guittot@xxxxxxxxxx; > saravanak@xxxxxxxxxx; 'Sudeep Holla' <sudeep.holla@xxxxxxx>; 'Rafael J. > Wysocki' <rjw@xxxxxxxxxxxxx>; 'Rob Herring' <robh+dt@xxxxxxxxxx>; linux- > pm@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Oggetto: Re: R: [RFC PATCH v3 0/2] Add Krait Cache Scaling support > > On 2020-09-03 12:23, Viresh Kumar wrote: > > On 31-08-20, 09:41, ansuelsmth@xxxxxxxxx wrote: > >> On 31-08-20, Sibi wrote: > >> > 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- > > > > I think this should happen nevertheless. You are doing DVFS for a > > device which isn't a CPU and devfreq looks to be the right place of > > doing so. > > > >> Isn't overkill to use a governor for such a task? > >> (3 range based on the cpufreq?) > > > > I am not sure about the governor part here, maybe it won't be required > > ? > > Yeah I don't see it being needed in ^^ > case as well. I just mentioned them as > an advantage in case you wanted to switch > to a different governor in the future. > > https://lore.kernel.org/lkml/d0bc8877-6d41-f54e-1c4c- > 2fadbb9dcd0b@xxxxxxxxxxx/ > > A devfreq governor tracking cpufreq was > generally accepted but using a cpufreq > notifier to achieve that was discouraged. > I read the patch discussion and it looks like at the very end they lost interest in pushing it. That would very fit what I need here so I'm asking how should I proceed? Keep the cpufreq notifier? Introduce a dedicated governor? Ask them to resume the pushing or try to include the changes to the passive governor by myself? > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > a Linux Foundation Collaborative Project.
