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Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant load-tracking support

From Sudeep Holla <sudeep.holla@arm.com>
Newsgroups linux.kernel
Subject Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant load-tracking support
Date 2017-07-13 14:50 +0200
Message-ID <u2LJ7-5H5-7@gated-at.bofh.it> (permalink)
References (3 earlier) <u0WSm-26b-5@gated-at.bofh.it> <u1FFM-4PO-9@gated-at.bofh.it> <u1WwW-74G-17@gated-at.bofh.it> <u24Xw-3TD-27@gated-at.bofh.it> <u2h8m-39O-23@gated-at.bofh.it>
Organization ARM

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On 12/07/17 05:09, Viresh Kumar wrote:
> On 11-07-17, 16:06, Dietmar Eggemann wrote:
>> But in the meantime we're convinced that cpufreq_driver_fast_switch() is
>> not the right place to call arch_set_freq_scale() since for (future)
>> arm/arm64 fast-switch driver, the return value of
>> cpufreq_driver->fast_switch() does not give us the information that the
>> frequency value did actually change.
> 
> Yeah, I saw your discussion with Peter on #linux-rt IRC and TBH I wasn't aware
> that we are going to do fast switching that way. Just trying to get
> understanding of that idea a bit..
> 
> So we will do fast switching from scheduler's point of view, i.e. we wouldn't
> schedule a kthread to change the frequency. But the real hardware still can't do
> that without sleeping, like if we have I2C somewhere in between. AFAIU, we will
> still have some kind of *software* bottom half to do that work, isn't it? And it
> wouldn't be that we have pushed some instructions to the hardware, which it can
> do a bit later.
> 

No the platforms we are considering are only where a standard firmware
interface is provided and the firmware deals with all those I2C/PMIC crap.

> For example, the regulator may be accessed via I2C and we need to program that
> before changing the clock. So, it will be done by some software code only.
> 

Software but just not Linux OSPM but some firmware(remote processors
presumably, can't imagine on the same processor though)

-- 
Regards,
Sudeep

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[PATCH v2 00/10] arm, arm64: frequency- and cpu-invariant accounting support for task scheduler Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-06 12:00 +0200
  [PATCH v2 08/10] arm64: wire frequency-invariant accounting support up to the task scheduler Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-06 12:00 +0200
    Re: [PATCH v2 08/10] arm64: wire frequency-invariant accounting  support up to the task scheduler Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-06 12:50 +0200
  [PATCH v2 03/10] drivers base/arch_topology: frequency-invariant load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-06 12:00 +0200
    Re: [PATCH v2 03/10] drivers base/arch_topology: frequency-invariant  load-tracking support Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-06 12:50 +0200
      Re: [PATCH v2 03/10] drivers base/arch_topology: frequency-invariant  load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-07 19:00 +0200
  [PATCH v2 05/10] arm: wire frequency-invariant accounting support up to the task scheduler Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-06 12:00 +0200
    Re: [PATCH v2 05/10] arm: wire frequency-invariant accounting  support up to the task scheduler Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-06 12:50 +0200
  [PATCH v2 02/10] cpufreq: provide data for frequency-invariant load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-06 12:00 +0200
    Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-06 12:50 +0200
      Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant load-tracking support "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-07-07 00:50 +0200
      Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-07 18:10 +0200
        Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support "Rafael J. Wysocki" <rafael@kernel.org> - 2017-07-07 18:20 +0200
          Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-07 19:10 +0200
            Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant load-tracking support "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-07-08 14:20 +0200
              Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-10 09:00 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant load-tracking support "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-07-10 15:00 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-11 08:50 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-11 17:30 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Sudeep Holla <sudeep.holla@arm.com> - 2017-07-13 14:50 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-13 15:10 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Sudeep Holla <sudeep.holla@arm.com> - 2017-07-13 16:10 +0200
              Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Peter Zijlstra <peterz@infradead.org> - 2017-07-10 11:40 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-10 11:50 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-10 12:40 +0200
              Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-10 14:10 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-11 08:10 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-11 17:10 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant load-tracking support "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-07-11 17:10 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-11 17:20 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-12 06:10 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Peter Zijlstra <peterz@infradead.org> - 2017-07-12 10:40 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-12 11:30 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Peter Zijlstra <peterz@infradead.org> - 2017-07-12 13:20 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant load-tracking support "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-07-13 01:30 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Peter Zijlstra <peterz@infradead.org> - 2017-07-13 10:00 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-13 10:50 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Peter Zijlstra <peterz@infradead.org> - 2017-07-13 13:20 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Sudeep Holla <sudeep.holla@arm.com> - 2017-07-13 16:10 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Peter Zijlstra <peterz@infradead.org> - 2017-07-13 16:50 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Sudeep Holla <sudeep.holla@arm.com> - 2017-07-13 17:10 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Sudeep Holla <sudeep.holla@arm.com> - 2017-07-13 15:00 +0200
                Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Sudeep Holla <sudeep.holla@arm.com> - 2017-07-13 14:50 +0200
        Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant  load-tracking support Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-10 08:50 +0200
  [PATCH v2 04/10] arm: wire cpufreq input data for frequency-invariant accounting up to the arch Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-06 12:00 +0200
    Re: [PATCH v2 04/10] arm: wire cpufreq input data for  frequency-invariant accounting up to the arch Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-06 12:50 +0200
      Re: [PATCH v2 04/10] arm: wire cpufreq input data for  frequency-invariant accounting up to the arch Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-10 17:20 +0200
        Re: [PATCH v2 04/10] arm: wire cpufreq input data for  frequency-invariant accounting up to the arch Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-11 08:40 +0200
  [PATCH v2 09/10] arm64: wire cpu-invariant accounting support up to the task scheduler Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-06 12:00 +0200
    Re: [PATCH v2 09/10] arm64: wire cpu-invariant accounting support up  to the task scheduler Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-06 12:50 +0200
  [PATCH v2 06/10] arm: wire cpu-invariant accounting support up to the task scheduler Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-06 12:00 +0200
    Re: [PATCH v2 06/10] arm: wire cpu-invariant accounting support up  to the task scheduler Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-06 12:50 +0200
  [PATCH v2 01/10] drivers base/arch_topology: free cpumask cpus_to_visit Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-06 12:00 +0200
    Re: [PATCH v2 01/10] drivers base/arch_topology: free cpumask  cpus_to_visit Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-06 12:30 +0200
      Re: [PATCH v2 01/10] drivers base/arch_topology: free cpumask  cpus_to_visit Juri Lelli <juri.lelli@arm.com> - 2017-07-06 13:00 +0200
        Re: [PATCH v2 01/10] drivers base/arch_topology: free cpumask  cpus_to_visit Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-06 13:20 +0200
          Re: [PATCH v2 01/10] drivers base/arch_topology: free cpumask  cpus_to_visit Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-07 18:00 +0200
  [PATCH v2 10/10] drivers base/arch_topology: inline cpu- and frequency-invariant accounting Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-06 12:00 +0200
    Re: [PATCH v2 10/10] drivers base/arch_topology: inline cpu- and  frequency-invariant accounting Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-06 13:00 +0200
      Re: [PATCH v2 10/10] drivers base/arch_topology: inline cpu- and  frequency-invariant accounting Dietmar Eggemann <dietmar.eggemann@arm.com> - 2017-07-10 17:20 +0200

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