From: Viresh Kumar <viresh.kumar@linaro.org>
To: Ionela Voinescu <ionela.voinescu@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
linux-pm@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Rafael Wysocki <rjw@rjwysocki.net>,
linux-kernel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sudeep Holla <sudeep.holla@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V3 1/2] topology: Allow multiple entities to provide sched_freq_tick() callback
Date: Wed, 17 Feb 2021 09:55:58 +0530 [thread overview]
Message-ID: <20210217042558.o4anjdkayzgqny55@vireshk-i7> (raw)
In-Reply-To: <20210217002422.GA17422@arm.com>
On 17-02-21, 00:24, Ionela Voinescu wrote:
> I think it could be merged in patch 1/2 as it's part of enabling the use
> of multiple sources of information for FIE. Up to you!
Sure.
> > static void amu_fie_setup(const struct cpumask *cpus)
> > {
> > - bool invariant;
> > int cpu;
> >
> > /* We are already set since the last insmod of cpufreq driver */
> > @@ -257,25 +256,10 @@ static void amu_fie_setup(const struct cpumask *cpus)
> >
> > cpumask_or(amu_fie_cpus, amu_fie_cpus, cpus);
> >
> > - invariant = topology_scale_freq_invariant();
> > -
> > - /* We aren't fully invariant yet */
> > - if (!invariant && !cpumask_equal(amu_fie_cpus, cpu_present_mask))
> > - return;
> > -
>
> You still need these checks, otherwise you could end up with only part
> of the CPUs setting a scale factor, when only part of the CPUs support
> AMUs and there is no cpufreq support for FIE.
Both supports_scale_freq_counters() and topology_scale_freq_invariant() take
care of this now and they will keep reporting the system as invariant until the
time all the CPUs have counters (in absence of cpufreq).
The topology_set_scale_freq_source() API is supposed to be called multiple
times, probably once for each policy and so I don't see a need of these checks
anymore.
> Small(ish) optimisation at the beginning of this function:
>
> if (cpumask_empty(&scale_freq_counters_mask))
> scale_freq_invariant = topology_scale_freq_invariant();
>
> This will save you a call to rebuild_sched_domains_energy(), which is
> quite expensive, when cpufreq supports FIE and we also have counters.
Good Point.
> After comments addressed,
>
> Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com>
Thanks.
> Tested-by: Ionela Voinescu <ionela.voinescu@arm.com>
Just out of curiosity, what exactly did you test and what was the setup ? :)
--
viresh
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next prev parent reply other threads:[~2021-02-17 4:28 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-28 10:48 [PATCH V3 0/2] cpufreq: cppc: Add support for frequency invariance Viresh Kumar
2021-01-28 10:48 ` [PATCH V3 1/2] topology: Allow multiple entities to provide sched_freq_tick() callback Viresh Kumar
2021-02-03 11:45 ` Ionela Voinescu
2021-02-05 9:14 ` Viresh Kumar
2021-02-17 0:24 ` Ionela Voinescu
2021-02-17 4:25 ` Viresh Kumar [this message]
2021-02-17 11:30 ` Ionela Voinescu
2021-02-17 11:40 ` Viresh Kumar
2021-02-17 11:57 ` Ionela Voinescu
2021-02-18 7:23 ` Viresh Kumar
2021-02-18 9:33 ` Viresh Kumar
2021-02-18 16:36 ` Ionela Voinescu
2021-02-19 4:58 ` Viresh Kumar
2021-02-19 9:44 ` Ionela Voinescu
2021-02-19 9:48 ` Viresh Kumar
2021-01-28 10:48 ` [PATCH V3 2/2] cpufreq: cppc: Add support for frequency invariance Viresh Kumar
2021-02-18 16:35 ` Ionela Voinescu
2021-02-22 11:00 ` Ionela Voinescu
2021-02-22 11:04 ` Viresh Kumar
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