Message-ID: <be2d96b0-63a6-42ea-a13b-1b9cf7f04694@amd.com>
Date: Thu, 5 Sep 2024 16:14:26 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: "Jones, Morgan" <Morgan.Jones@...sat.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Sasha Levin <sashal@...nel.org>
Cc: "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 David Arcari <darcari@...hat.com>,
 Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>,
 "rafael@...nel.org" <rafael@...nel.org>,
 "viresh.kumar@...aro.org" <viresh.kumar@...aro.org>,
 "gautham.shenoy@....com" <gautham.shenoy@....com>,
 "perry.yuan@....com" <perry.yuan@....com>,
 "skhan@...uxfoundation.org" <skhan@...uxfoundation.org>,
 "li.meng@....com" <li.meng@....com>, "ray.huang@....com"
 <ray.huang@....com>, "stable@...r.kernel.org" <stable@...r.kernel.org>,
 Linux kernel regressions list <regressions@...ts.linux.dev>
Subject: linux-6.6.y regression on amd-pstate

+ stable
+ regressions
New subject

Great news.

Greg, Sasha,

Can you please pull in these 3 commits specifically to 6.6.y to fix a 
regression that was reported by Morgan in 6.6.y:

commit 12753d71e8c5 ("ACPI: CPPC: Add helper to get the highest 
performance value")
commit ed429c686b79 ("cpufreq: amd-pstate: Enable amd-pstate preferred 
core support")
commit 3d291fe47fe1 ("cpufreq: amd-pstate: fix the highest frequency 
issue which limits performance")

Further details are below.

Thanks!

On 9/5/2024 16:09, Jones, Morgan wrote:
> Mario,
> 
> Confirmed. Thank you for the help! Slightly different refs on my end:
> 
> Remotes:
> 
> next    https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git (fetch)
> next    https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git (push)
> origin  git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git (fetch)
> origin  git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git (push)
> superm1 https://git.kernel.org/pub/scm/linux/kernel/git/superm1/linux.git/ (fetch)
> superm1 https://git.kernel.org/pub/scm/linux/kernel/git/superm1/linux.git/ (push)
> torvalds        git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git (fetch)
> torvalds        git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git (push)
> 
> Patches:
> 
> git format-patch 12753d71e8c5^..12753d71e8c5
> git format-patch f3a052391822b772b4e27f2594526cf1eb103cab^..f3a052391822b772b4e27f2594526cf1eb103cab
> git format-patch bf202e654bfa57fb8cf9d93d4c6855890b70b9c4^..bf202e654bfa57fb8cf9d93d4c6855890b70b9c4
> 
> Results:
> 
> Linux redact 6.6.48 #1-NixOS SMP PREEMPT_DYNAMIC Tue Jan  1 00:00:00 UTC 1980 x86_64 GNU/Linux
> 
> analyzing CPU 56:
>    driver: amd-pstate-epp
>    CPUs which run at the same hardware frequency: 56
>    CPUs which need to have their frequency coordinated by software: 56
>    maximum transition latency:  Cannot determine or is not supported.
>    hardware limits: 400 MHz - 3.35 GHz
>    available cpufreq governors: performance powersave
>    current policy: frequency should be within 400 MHz and 3.35 GHz.
>                    The governor "performance" may decide which speed to use
>                    within this range.
>    current CPU frequency: Unable to call hardware
>    current CPU frequency: 2.09 GHz (asserted by call to kernel)
>    boost state support:
>      Supported: yes
>      Active: yes
>      AMD PSTATE Highest Performance: 255. Maximum Frequency: 3.35 GHz.
>      AMD PSTATE Nominal Performance: 152. Nominal Frequency: 2.00 GHz.
>      AMD PSTATE Lowest Non-linear Performance: 115. Lowest Non-linear Frequency: 1.51 GHz.
>      AMD PSTATE Lowest Performance: 31. Lowest Frequency: 400 MHz.
> 
> And our builds are back to being fast with `amd_pstate=active amd_prefcore=enable amd_pstate.shared_mem=1`.
> 
> Morgan
> 
> -----Original Message-----
> From: Mario Limonciello <mario.limonciello@....com>
> Sent: Thursday, September 5, 2024 8:12 AM
> To: Jones, Morgan <Morgan.Jones@...sat.com>
> Cc: linux-pm@...r.kernel.org; linux-kernel@...r.kernel.org; David Arcari <darcari@...hat.com>; Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>; rafael@...nel.org; viresh.kumar@...aro.org; gautham.shenoy@....com; perry.yuan@....com; skhan@...uxfoundation.org; li.meng@....com; ray.huang@....com
> Subject: Re: [EXTERNAL] Re: [PATCH v2 2/2] cpufreq/amd-pstate: Fix the scaling_max_freq setting on shared memory CPPC systems
> 
> Hi Morgan,
> 
> Please apply these 3 commits:
> 
> commit 12753d71e8c5 ("ACPI: CPPC: Add helper to get the highest performance value") commit ed429c686b79 ("cpufreq: amd-pstate: Enable amd-pstate preferred core support") commit 3d291fe47fe1 ("cpufreq: amd-pstate: fix the highest frequency issue which limits performance")
> 
> The first two should help your system, the third will prevent introducing a regression on a different one.
> 
> Assuming that works we should ask @stable to pull all 3 in to fix this regression.
> 
> Thanks,
> 
> On 9/4/2024 08:57, Mario Limonciello wrote:
>> Morgan,
>>
>> I was referring specfiically to the version that landed in Linus' tree:
>> https://urldefense.us/v3/__https://git.kernel.org/torvalds/c/8164f7433
>> 264__;!!C5Asm8uRnZQmlRln!aIZEDEbIUKD7OrxN0b0KjoqKYDL2yMkwk4EK7x_oSnyHQ
>> 6MEq7yt6JHjd0TD9DgEYEWDcF58OKL8c7G11bT3dSqL8eM$
>>
>> But yeah it's effectively the same thing.  In any case, it's not the
>> solution.
>>
>> We had some internal discussion and suspect this is due to missing
>> prefcore patches in 6.6 as that feature landed in 6.9.  We'll try to
>> reproduce this on a Rome system and come back with our findings and
>> suggestions what to do.
>>
>> Thanks,
>>
> 

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