[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <12290212.O9o76ZdvQC@natalenko.name>
Date: Wed, 20 Sep 2023 21:34:17 +0200
From: Oleksandr Natalenko <oleksandr@...alenko.name>
To: Huang Rui <ray.huang@....com>, Meng Li <li.meng@....com>,
Mario Limonciello <mario.limonciello@....com>
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
x86@...nel.org, linux-acpi@...r.kernel.org,
Shuah Khan <skhan@...uxfoundation.org>,
linux-kselftest@...r.kernel.org,
Nathan Fontenot <nathan.fontenot@....com>,
Deepak Sharma <deepak.sharma@....com>,
Alex Deucher <alexander.deucher@....com>,
Shimmer Huang <shimmer.huang@....com>,
Perry Yuan <Perry.Yuan@....com>,
Xiaojian Du <Xiaojian.Du@....com>,
Viresh Kumar <viresh.kumar@...aro.org>,
Borislav Petkov <bp@...en8.de>,
"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH V7 0/7] amd-pstate preferred core
Hello.
On středa 20. září 2023 18:56:09 CEST Mario Limonciello wrote:
> > When applied on top of v6.5.3 this breaks turbo on my 5950X after suspend/resume cycle. Please see the scenario description below.
> >
> > If I boot v6.5.3 + this patchset, then `turbostat` reports ~4.9 GHz on core 0 where `taskset -c 0 dd if=/dev/zero of=/dev/null` is being run.
> >
> > After I suspend the machine and then resume it, and run `dd` again, `turbostat` reports the core to be capped to a stock frequency of ~3.4 GHz. Rebooting the machine fixes this, and the CPU can boost again.
> >
> > If this patchset is reverted, then the CPU can turbo after suspend/resume cycle just fine.
> >
> > I'm using `amd_pstate=guided`.
> >
> > Is this behaviour expected?
>
> To help confirm where the issue is, can I ask you to do three
> experiments with the patch series applied:
>
> 1) 'amd_pstate=active' on your kernel command line.
The issue is reproducible. If I toggle the governor in cpupower to `powersave` and back to `performance`, boost is restored.
> 2) 'amd_pstate=active amd_prefcore=disable' on your kernel command line.
The issue is not reproducible.
> 3) 'amd_pstate=guided amd_prefcore=disable' on your kernel command line.
The issue is not reproducible.
I should also mention that in my initial configuration I use `amd_pstate=guided` and `schedutil`. If I switch to `performance` after suspend-resume cycle, the boost is restored. However, if I switch back to `schedutil`, the freq is capped.
Does this info help?
> Looking through the code, I anticipate from your report that it
> reproduces on "1" but not "2" and "3".
>
> Meng,
>
> Can you try to repro?
>
> I think that it's probably a call to amd_pstate_init_prefcore() missing
> from amd_pstate_cpu_resume() and also amd_pstate_epp_resume().
--
Oleksandr Natalenko (post-factum)
Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)
Powered by blists - more mailing lists