From: "Rafael J. Wysocki" <email@example.com> To: Ionela Voinescu <firstname.lastname@example.org> Cc: Linux ARM <email@example.com>, Rob Herring <firstname.lastname@example.org>, Daniel Lezcano <email@example.com>, "firstname.lastname@example.org" <email@example.com>, Viresh Kumar <firstname.lastname@example.org>, Linux PM <email@example.com>, "Rafael J. Wysocki" <firstname.lastname@example.org>, Linux Kernel Mailing List <email@example.com>, Sudeep Holla <firstname.lastname@example.org>, Nicola Mazzucato <email@example.com>, Viresh Kumar <firstname.lastname@example.org>, Chris Redpath <email@example.com>, Morten Rasmussen <firstname.lastname@example.org>, Lukasz Luba <email@example.com> Subject: Re: [PATCH v2 2/2] [RFC] CPUFreq: Add support for cpu-perf-dependencies Date: Tue, 13 Oct 2020 13:53:37 +0200 [thread overview] Message-ID: <CAJZ5v0hMtPARYezJEZqeUZBsyaSggQvtvvfEvONhz6Z=Y32bhQ@mail.gmail.com> (raw) In-Reply-To: <20201012220132.GA1715@arm.com> On Tue, Oct 13, 2020 at 12:01 AM Ionela Voinescu <firstname.lastname@example.org> wrote: > > Hey Lukasz, > > I think after all this discussion (in our own way of describing things) > we agree on how the current cpufreq based FIE implementation is affected > in systems that use hardware coordination. > > What we don't agree on is the location where that implementation (that > uses the new mask and aggregation) should be. > > On Monday 12 Oct 2020 at 19:19:29 (+0100), Lukasz Luba wrote: > [..] > > The previous FIE implementation where arch_set_freq_scale() > > was called from the drivers, was better suited for this issue. > > Driver could just use internal dependency cpumask or even > > do the aggregation to figure out the max freq for cluster > > if there is a need, before calling arch_set_freq_scale(). > > > > It is not perfect solution for software FIE, but one of possible > > when there is no hw counters. > > > [..] > > > Difference between new FIE and old FIE (from v5.8) is that the new one > > purely relies on schedutil max freq value (which will now be missing), > > while the old FIE was called by the driver and thus it was an option to > > fix only the affected cpufreq driver . > > > > My final argument is that now you have 2 drivers that would need this > support, next you'll have 3 (the new mediatek driver), and in the future > there will be more. So why limit and duplicate this functionality in the > drivers? Why not make it generic for all drivers to use if the system > is using hardware coordination? > > Additionally, I don't think drivers should not even need to know about > these dependency/clock domains. They should act at the level of the > policy, which in this case will be at the level of each CPU. The policies come from the driver, though. The driver decides how many CPUs will be there in a policy and how to handle them at the initialization time. The core has no idea whether or not there is HW coordination in the system, the driver is expected to know that and take that into account. Accordingly, it looks like there should be an option for drivers to arrange things in the most convenient way (from their perspective) and that option has gone away now. _______________________________________________ linux-arm-kernel mailing list email@example.com http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-10-13 11:55 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 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 [this message] 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='CAJZ5v0hMtPARYezJEZqeUZBsyaSggQvtvvfEvONhz6Z=Y32bhQ@mail.gmail.com' \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --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).