[AMD Official Use Only - General]
Hi Natalenko and Mario:
-----Original Message----- From: Limonciello, Mario Mario.Limonciello@amd.com Sent: Thursday, September 21, 2023 4:12 AM To: Oleksandr Natalenko oleksandr@natalenko.name; Huang, Ray Ray.Huang@amd.com; Meng, Li (Jassmine) Li.Meng@amd.com Cc: linux-pm@vger.kernel.org; linux-kernel@vger.kernel.org; x86@kernel.org; linux-acpi@vger.kernel.org; Shuah Khan skhan@linuxfoundation.org; linux-kselftest@vger.kernel.org; Fontenot, Nathan Nathan.Fontenot@amd.com; Sharma, Deepak Deepak.Sharma@amd.com; Deucher, Alexander Alexander.Deucher@amd.com; Huang, Shimmer Shimmer.Huang@amd.com; Yuan, Perry Perry.Yuan@amd.com; Du, Xiaojian Xiaojian.Du@amd.com; Viresh Kumar viresh.kumar@linaro.org; Borislav Petkov bp@alien8.de; Rafael J . Wysocki rafael.j.wysocki@intel.com Subject: Re: [PATCH V7 0/7] amd-pstate preferred core
On 9/20/2023 14:34, Oleksandr Natalenko wrote:
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:
- '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.
- 'amd_pstate=active amd_prefcore=disable' on your kernel command
line.
The issue is not reproducible.
- '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?
Yeah, it matches my expectations for this issue you reported. Thanks!
Jassmine can dig into a fix for another spin of this series.
[Meng, Li (Jassmine)] Thank you very much! I will fix this issue in the next patches.
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().