From: Ionela Voinescu <ionela.voinescu@arm.com>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com,
maz@kernel.org, suzuki.poulose@arm.com, sudeep.holla@arm.com,
lukasz.luba@arm.com, rjw@rjwysocki.net, peterz@infradead.org,
mingo@redhat.com, vincent.guittot@linaro.org,
viresh.kumar@linaro.org, linux-arm-kernel@lists.infradead.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pm@vger.kernel.org
Subject: Re: [PATCH v3 5/7] cpufreq: add function to get the hardware max frequency
Date: Thu, 13 Feb 2020 12:59:18 +0000 [thread overview]
Message-ID: <20200213125918.GA2397@arm.com> (raw)
In-Reply-To: <b63a4a47-99e5-9c71-73be-740aedde4714@arm.com>
On Thursday 13 Feb 2020 at 11:59:56 (+0000), Valentin Schneider wrote:
> On 2/11/20 6:45 PM, Ionela Voinescu wrote:
> > +/**
> > + * cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU
> > + * @cpu: CPU number
> > + *
> > + * The default return value is the max_freq field of cpuinfo.
> > + */
> > +__weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu)
> > +{
> > + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
> > + unsigned int ret_freq = 0;
> > +
> > + if (policy) {
> > + ret_freq = policy->cpuinfo.max_freq;
> > + cpufreq_cpu_put(policy);
>
> What about intel_pstate / turbo stuff? IIRC one of Giovanni's issues was that
> turbo freq is not always reported as the max freq. Dunno if we can do
> anything about it; at the very least maybe document the caveat?
>
Okay, I can add details in the description in regards to potential
reasons to overwrite this function. But basically this is one of the
reasons for making this a weak function. The best information we can
generically get for maximum hardware frequency is cpuinfo.max_freq.
But if platforms have the possibility to obtain this differently from
either hardware or firmware they can overwrite this.
Thanks,
Ionela.
> > + }
> > +
> > + return ret_freq;
> > +}
> > +EXPORT_SYMBOL(cpufreq_get_hw_max_freq);
> > +
> > static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
> > {
> > if (unlikely(policy_is_inactive(policy)))
>
next prev parent reply other threads:[~2020-02-13 12:59 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 18:45 [PATCH v3 0/7] arm64: ARMv8.4 Activity Monitors support Ionela Voinescu
2020-02-11 18:45 ` [PATCH v3 1/7] arm64: add support for the AMU extension v1 Ionela Voinescu
2020-02-12 11:30 ` Suzuki Kuruppassery Poulose
2020-02-12 14:54 ` Valentin Schneider
2020-02-12 16:10 ` Ionela Voinescu
2020-02-12 16:20 ` Suzuki Kuruppassery Poulose
2020-02-12 18:20 ` Ionela Voinescu
2020-02-12 19:24 ` Suzuki K Poulose
2020-02-12 20:19 ` Ionela Voinescu
2020-02-12 16:24 ` Vladimir Murzin
2020-02-12 18:27 ` Ionela Voinescu
2020-02-11 18:45 ` [PATCH v3 2/7] arm64: trap to EL1 accesses to AMU counters from EL0 Ionela Voinescu
2020-02-12 11:44 ` Suzuki Kuruppassery Poulose
2020-02-12 15:36 ` Valentin Schneider
2020-02-11 18:45 ` [PATCH v3 3/7] arm64/kvm: disable access to AMU registers from kvm guests Ionela Voinescu
2020-02-12 15:36 ` Valentin Schneider
2020-02-12 16:33 ` Suzuki Kuruppassery Poulose
2020-02-11 18:45 ` [PATCH v3 4/7] Documentation: arm64: document support for the AMU extension Ionela Voinescu
2020-02-12 15:36 ` Valentin Schneider
2020-02-11 18:45 ` [PATCH v3 5/7] cpufreq: add function to get the hardware max frequency Ionela Voinescu
2020-02-12 4:14 ` Viresh Kumar
2020-02-13 11:59 ` Valentin Schneider
2020-02-13 12:59 ` Ionela Voinescu [this message]
2020-02-13 15:22 ` Valentin Schneider
2020-02-11 18:45 ` [PATCH v3 6/7] arm64: use activity monitors for frequency invariance Ionela Voinescu
2020-02-12 18:59 ` Lukasz Luba
2020-02-13 9:47 ` Ionela Voinescu
2020-02-17 16:59 ` Valentin Schneider
2020-02-23 18:49 ` Ionela Voinescu
2020-02-11 18:45 ` [PATCH v3 7/7] clocksource/drivers/arm_arch_timer: validate arch_timer_rate Ionela Voinescu
2020-02-12 9:30 ` Valentin Schneider
2020-02-12 10:32 ` Ionela Voinescu
2020-02-12 10:01 ` Lukasz Luba
2020-02-12 10:12 ` Marc Zyngier
2020-02-12 10:54 ` Ionela Voinescu
2020-02-12 10:55 ` Lukasz Luba
2020-02-12 11:10 ` Marc Zyngier
2020-02-12 11:43 ` Lukasz Luba
2020-02-12 11:12 ` Valentin Schneider
2020-02-14 0:35 ` Thomas Gleixner
2020-02-14 15:45 ` Ionela Voinescu
2020-02-14 15:57 ` Ionela Voinescu
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