From: Lukasz Luba <lukasz.luba@arm.com>
To: Florian Fainelli <f.fainelli@gmail.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org
Cc: viresh.kumar@linaro.org, rjw@rjwysocki.net,
cristian.marussi@arm.com, sudeep.holla@arm.com
Subject: Re: [PATCH 0/4] CPUFreq statistics retrieved by drivers
Date: Wed, 5 Aug 2020 12:04:42 +0100 [thread overview]
Message-ID: <119ce268-18dc-7a4c-b0b2-3a66ff9ff4b0@arm.com> (raw)
In-Reply-To: <a3354ae8-f40f-83f2-d6eb-7f588af75e97@gmail.com>
On 8/4/20 6:27 PM, Florian Fainelli wrote:
>
>
> On 7/29/2020 8:12 AM, Lukasz Luba wrote:
>> Hi all,
>>
>> The existing CPUFreq framework does not tracks the statistics when the
>> 'fast switch' is used or when firmware changes the frequency independently
>> due to e.g. thermal reasons. However, the firmware might track the frequency
>> changes and expose this to the kernel.
>
> Or the firmware might have changed the CPU frequency in response to a
> request from the secure world for instance.
Possible
>
>>
>> This patch set aims to introduce CPUfreq statistics gathered by firmware
>> and retrieved by CPUFreq driver. It would require a new API functions
>> in the CPUFreq, which allows to poke drivers to get these stats.
>
> From a debugging perspective, it would be helpful if the firmware
> maintained statistics were exposed as a super-set of the Linux cpufreq
> statistics and aggregated into them such that you could view the normal
> world vs. secure world residency of a given frequency point. This would
> help because a lot of times, Linux requests freq X, but the secure world
> requires freq Y (with X >= Y) and people do not really understand why
> the resulting power usage is higher for instance.
>
> What are your thoughts on this?
>
I know that Viresh is going to develop patches and improve these
cpufreq stats framework. Maybe he also had this 'aggregation' in mind.
I will leave it him.
Thank you for your feedback.
Regards,
Lukasz
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next prev parent reply other threads:[~2020-08-05 11:06 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-29 15:12 [PATCH 0/4] CPUFreq statistics retrieved by drivers Lukasz Luba
2020-07-29 15:12 ` [PATCH 1/4] cpufreq: Add support for statistics read from drivers Lukasz Luba
2020-07-29 15:12 ` [PATCH 2/4] scmi: perf: Extend protocol to support performance statistics Lukasz Luba
2020-07-31 1:50 ` kernel test robot
2020-07-31 15:15 ` Cristian Marussi
2020-08-04 11:10 ` Lukasz Luba
2020-07-29 15:12 ` [PATCH 3/4] cpufreq: scmi: Move scmi_cpufreq_driver structure to the top Lukasz Luba
2020-07-29 15:12 ` [PATCH 4/4] cpufreq: scmi: Read statistics from FW shared memory Lukasz Luba
2020-07-30 8:53 ` [PATCH 0/4] CPUFreq statistics retrieved by drivers Viresh Kumar
2020-07-30 9:10 ` Sudeep Holla
2020-07-30 9:36 ` Lukasz Luba
2020-07-31 15:56 ` Sudeep Holla
2020-08-04 17:19 ` Florian Fainelli
2020-08-05 12:36 ` Sudeep Holla
2020-08-04 5:35 ` Viresh Kumar
2020-08-04 10:29 ` Lukasz Luba
2020-08-04 10:38 ` Viresh Kumar
2020-08-04 10:44 ` Lukasz Luba
2020-09-02 7:26 ` Viresh Kumar
2020-08-04 17:27 ` Florian Fainelli
2020-08-05 11:04 ` Lukasz Luba [this message]
2020-08-05 13:04 ` Viresh Kumar
2020-08-05 16:03 ` Sudeep Holla
2020-08-05 17:33 ` Florian Fainelli
2020-08-06 13:37 ` Sudeep Holla
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