linux-kernel - Re: [PATCH v5 0/2] add SW BOOST support for CPPC

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Date:   Fri, 5 Jun 2020 14:22:25 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>,
        Xiongfeng Wang <wangxiongfeng2@...wei.com>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Souvik Chakravarty <Souvik.Chakravarty@....com>,
        Thanu.Rangarajan@....com, Sudeep Holla <Sudeep.Holla@....com>,
        Hanjun Guo <guohanjun@...wei.com>,
        John Garry <john.garry@...wei.com>,
        Jonathan Cameron <jonathan.cameron@...wei.com>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 0/2] add SW BOOST support for CPPC

On Tue, Jun 2, 2020 at 7:16 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
>
> On 30-05-20, 10:08, Xiongfeng Wang wrote:
> > ACPI spec 6.2 section 8.4.7.1 provide the following two CPC registers.
> >
> > "Highest performance is the absolute maximum performance an individual
> > processor may reach, assuming ideal conditions. This performance level
> > may not be sustainable for long durations, and may only be achievable if
> > other platform components are in a specific state; for example, it may
> > require other processors be in an idle state.
> >
> > Nominal Performance is the maximum sustained performance level of the
> > processor, assuming ideal operating conditions. In absence of an
> > external constraint (power, thermal, etc.) this is the performance level
> > the platform is expected to be able to maintain continuously. All
> > processors are expected to be able to sustain their nominal performance
> > state simultaneously."
> >
> > We can use Highest Performance as the max performance in boost mode and
> > Nomial Performance as the max performance in non-boost mode. If the
> > Highest Performance is greater than the Nominal Performance, we assume
> > SW BOOST is supported.
> >
> > Changelog:
> >
> > v4 -> v5:
> >       add 'cpu_hotplug_lock' before calling '.set_boost'
> > v3 -> v4:
> >       run 'boost_set_msr_each' for each CPU in the policy rather than
> >       each CPU in the system for 'acpi-cpufreq'
> >       add 'Suggested-by'
> >
> > Xiongfeng Wang (2):
> >   cpufreq: change '.set_boost' to act on only one policy
> >   CPPC: add support for SW BOOST
> >
> >  drivers/cpufreq/acpi-cpufreq.c | 14 ++++++-----
> >  drivers/cpufreq/cppc_cpufreq.c | 39 +++++++++++++++++++++++++++--
> >  drivers/cpufreq/cpufreq.c      | 57 +++++++++++++++++++++++-------------------
> >  include/linux/cpufreq.h        |  2 +-
> >  4 files changed, 77 insertions(+), 35 deletions(-)
>
> Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

Both patches have been applied as 5.8-rc material with slightly
modified subjects and the changelog of patch [1/2] has been updated.

Thanks!