From: Ionela Voinescu <ionela.voinescu@arm.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Will Deacon <will@kernel.org>,
Russell King - ARM Linux <linux@armlinux.org.uk>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Linux PM <linux-pm@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Valentin Schneider <valentin.schneider@arm.com>
Subject: Re: [PATCH v2 1/7] cpufreq: move invariance setter calls in cpufreq core
Date: Mon, 3 Aug 2020 15:16:34 +0100 [thread overview]
Message-ID: <20200803141634.GA30107@arm.com> (raw)
In-Reply-To: <CAJZ5v0gOJXtpF4iy2v+Jbv9y9QZsAtEREMQwWv0u7Zks0Fvp1A@mail.gmail.com>
Hi Rafael,
On Monday 03 Aug 2020 at 15:46:59 (+0200), Rafael J. Wysocki wrote:
> On Mon, Aug 3, 2020 at 3:26 PM Ionela Voinescu <ionela.voinescu@arm.com> wrote:
> >
> > Hi guys,
> >
> > On Thursday 30 Jul 2020 at 09:11:28 (+0530), Viresh Kumar wrote:
> > > On 27-07-20, 15:48, Rafael J. Wysocki wrote:
> > > > On Wed, Jul 22, 2020 at 11:38 AM Ionela Voinescu
> > > > <ionela.voinescu@arm.com> wrote:
> > > > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > > > > index 036f4cc42ede..bac4101546db 100644
> > > > > --- a/drivers/cpufreq/cpufreq.c
> > > > > +++ b/drivers/cpufreq/cpufreq.c
> > > > > @@ -2058,9 +2058,16 @@ EXPORT_SYMBOL(cpufreq_unregister_notifier);
> > > > > unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
> > > > > unsigned int target_freq)
> > > > > {
> > > > > + unsigned int freq;
> > > > > +
> > > > > target_freq = clamp_val(target_freq, policy->min, policy->max);
> > > > > + freq = cpufreq_driver->fast_switch(policy, target_freq);
> > > > > +
> > > > > + if (freq)
> > > > > + arch_set_freq_scale(policy->related_cpus, freq,
> > > > > + policy->cpuinfo.max_freq);
> > > >
> > > > Why can't arch_set_freq_scale() handle freq == 0?
> > >
> >
> > Sorry, I seem to have missed this question the first time around.
> >
> > arch_set_freq_scale() could handle freq == 0, but given that freq == 0
> > is signaling an error here, I do believe this check is well placed, to
> > prevent a useless call to arch_set_freq_scale(). Also [1]:
>
> So let me rephrase:
>
> Doesn't this check add overhead in the empty arch_set_freq_scale() case?
Yes, you are right, I did not consider that. I can add a patch for the
arch_topology driver's arch_set_freq_scale() to handle this and we can
remove it from here.
Thank you for pointing this out,
Ionela.
next prev parent reply other threads:[~2020-08-03 14:16 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-22 9:37 [PATCH v2 0/7] cpufreq: improve frequency invariance support Ionela Voinescu
2020-07-22 9:37 ` [PATCH v2 1/7] cpufreq: move invariance setter calls in cpufreq core Ionela Voinescu
2020-07-27 13:48 ` Rafael J. Wysocki
2020-07-29 9:03 ` Ionela Voinescu
2020-07-30 3:41 ` Viresh Kumar
2020-08-03 13:26 ` Ionela Voinescu
2020-08-03 13:46 ` Rafael J. Wysocki
2020-08-03 14:16 ` Ionela Voinescu [this message]
2020-07-22 9:37 ` [PATCH v2 2/7] cpufreq: set invariance scale factor on transition end Ionela Voinescu
2020-07-27 13:52 ` Rafael J. Wysocki
2020-07-29 9:14 ` Ionela Voinescu
2020-07-30 4:13 ` Viresh Kumar
2020-08-03 13:58 ` Ionela Voinescu
2020-08-04 6:26 ` Viresh Kumar
2020-08-05 10:35 ` Ionela Voinescu
2020-07-22 9:37 ` [PATCH v2 3/7] arch_topology: disable frequency invariance for CONFIG_BL_SWITCHER Ionela Voinescu
2020-07-30 4:24 ` Viresh Kumar
2020-07-30 10:29 ` Dietmar Eggemann
2020-07-31 15:48 ` Sudeep Holla
2020-08-03 14:39 ` Ionela Voinescu
2020-08-04 6:30 ` Viresh Kumar
2020-08-10 9:01 ` Ionela Voinescu
2020-07-22 9:37 ` [PATCH v2 4/7] cpufreq: report whether cpufreq supports Frequency Invariance (FI) Ionela Voinescu
2020-07-27 14:02 ` Rafael J. Wysocki
2020-07-29 14:39 ` Ionela Voinescu
2020-07-30 4:43 ` Viresh Kumar
2020-08-03 15:24 ` Ionela Voinescu
2020-08-04 6:46 ` Viresh Kumar
2020-08-05 10:35 ` Ionela Voinescu
2020-07-22 9:37 ` [PATCH v2 5/7] arch_topology,cpufreq,sched/core: constify arch_* cpumasks Ionela Voinescu
2020-07-30 11:43 ` Catalin Marinas
2020-07-22 9:37 ` [PATCH v2 6/7] arch_topology,arm,arm64: define arch_scale_freq_invariant() Ionela Voinescu
2020-07-30 11:44 ` Catalin Marinas
2020-07-22 9:37 ` [PATCH v2 7/7] cpufreq: make schedutil the default for arm and arm64 Ionela Voinescu
2020-07-30 4:54 ` Viresh Kumar
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