[AMD Official Use Only - General] Hi Natalenko and Mario:
> -----Original Message----- > From: Limonciello, Mario <mario.limoncie...@amd.com> > Sent: Thursday, September 21, 2023 4:12 AM > To: Oleksandr Natalenko <oleksa...@natalenko.name>; Huang, Ray > <ray.hu...@amd.com>; Meng, Li (Jassmine) <li.m...@amd.com> > Cc: linux...@vger.kernel.org; linux-ker...@vger.kernel.org; > x...@kernel.org; linux-a...@vger.kernel.org; Shuah Khan > <sk...@linuxfoundation.org>; linux-kselftest@vger.kernel.org; Fontenot, > Nathan <nathan.fonte...@amd.com>; Sharma, Deepak > <deepak.sha...@amd.com>; Deucher, Alexander > <alexander.deuc...@amd.com>; Huang, Shimmer > <shimmer.hu...@amd.com>; Yuan, Perry <perry.y...@amd.com>; Du, > Xiaojian <xiaojian...@amd.com>; Viresh Kumar <viresh.ku...@linaro.org>; > Borislav Petkov <b...@alien8.de>; Rafael J . Wysocki > <rafael.j.wyso...@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: > >> > >> 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? > > > > 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(). > >
