linux-kernel - Re: [PATCH v2 1/3] ACPI: processor: perflib: Use the "no limit" frequency QoS

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Message-ID: <mafs0zga0ds30.fsf_-_@amazon.de>
Date:   Mon, 30 Jan 2023 15:17:55 +0100
From:   Pratyush Yadav <ptyadav@...zon.de>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
CC:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux ACPI <linux-acpi@...r.kernel.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Subject: Re: [PATCH v2 1/3] ACPI: processor: perflib: Use the "no limit"
 frequency QoS

Hi Rafael,

On Thu, Dec 29 2022, Rafael J. Wysocki wrote:

> On Thu, Dec 29, 2022 at 1:58 PM Pratyush Yadav <ptyadav@...zon.de> wrote:
>>
>> Hi Rafael,
>>
>> On Wed, Dec 28 2022, Rafael J. Wysocki wrote:
>> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>> >
>> > When _PPC returns 0, it means that the CPU frequency is not limited by
>> > the platform firmware, so make acpi_processor_get_platform_limit()
>> > update the frequency QoS request used by it to "no limit" in that case.
>> >
>> > This addresses a problem with limiting CPU frequency artificially on
>> > some systems after CPU offline/online to the frequency that corresponds
>> > to the first entry in the _PSS return package.
>> >
>> > Reported-by: Pratyush Yadav <ptyadav@...zon.de>
>> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>> > ---
[...]
>>
>> One small thing I noticed: in acpi_processor_ppc_init() "no limit" value
>> is set to INT_MAX and here it is set to FREQ_QOS_MAX_DEFAULT_VALUE. Both
>> should evaluate to the same value but I think it would be nice if the
>> same thing is used in both places. Perhaps you can fix that up when
>> applying?
>
> Yes, I'll do that.

Following up on this series. I do not see it queued anywhere in the
linux-pm [0] tree. I would like to have this in the v6.3 merge window if
possible.

[0] https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/

-- 
Regards,
Pratyush Yadav



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