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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <mafs0v8kodp14.fsf_-_@amazon.de>
Date:   Mon, 30 Jan 2023 16:23:51 +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 Mon, Jan 30 2023, Rafael J. Wysocki wrote:
> On Mon, Jan 30, 2023 at 3:18 PM Pratyush Yadav <ptyadav@...zon.de> wrote:
>>
>> 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/
>
> It's already in the mainline:
>
> e8a0e30b742f cpufreq: intel_pstate: Drop ACPI _PSS states table patching
> 99387b016022 ACPI: processor: perflib: Avoid updating frequency QoS
> unnecessarily
> c02d5feb6e2f ACPI: processor: perflib: Use the "no limit" frequency QoS

Hmm, I skimmed through the git log and did not spot any of these. Seems
like they were buried deeper in the logs due to merges. I can see them
now. My bad.

-- 
Regards,
Pratyush Yadav



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879