[AMD Official Use Only - General] Hi Oleksandr: > -----Original Message----- > From: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx> > Sent: Monday, October 9, 2023 2:55 PM > To: Rafael J . Wysocki <rafael.j.wysocki@xxxxxxxxx>; Huang, Ray > <Ray.Huang@xxxxxxx>; Meng, Li (Jassmine) <Li.Meng@xxxxxxx> > Cc: linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > x86@xxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; Shuah Khan > <skhan@xxxxxxxxxxxxxxxxxxx>; linux-kselftest@xxxxxxxxxxxxxxx; Fontenot, > Nathan <Nathan.Fontenot@xxxxxxx>; Sharma, Deepak > <Deepak.Sharma@xxxxxxx>; Deucher, Alexander > <Alexander.Deucher@xxxxxxx>; Limonciello, Mario > <Mario.Limonciello@xxxxxxx>; Huang, Shimmer > <Shimmer.Huang@xxxxxxx>; Yuan, Perry <Perry.Yuan@xxxxxxx>; Du, > Xiaojian <Xiaojian.Du@xxxxxxx>; Viresh Kumar <viresh.kumar@xxxxxxxxxx>; > Borislav Petkov <bp@xxxxxxxxx>; Meng, Li (Jassmine) <Li.Meng@xxxxxxx> > Subject: Re: [PATCH V8 0/7] amd-pstate preferred core > > Hello. > > On pondělí 9. října 2023 4:49:25 CEST Meng Li wrote: > > Hi all: > > > > The core frequency is subjected to the process variation in semiconductors. > > Not all cores are able to reach the maximum frequency respecting the > > infrastructure limits. Consequently, AMD has redefined the concept of > > maximum frequency of a part. This means that a fraction of cores can > > reach maximum frequency. To find the best process scheduling policy > > for a given scenario, OS needs to know the core ordering informed by > > the platform through highest performance capability register of the CPPC > interface. > > > > Earlier implementations of amd-pstate preferred core only support a > > static core ranking and targeted performance. Now it has the ability > > to dynamically change the preferred core based on the workload and > > platform conditions and accounting for thermals and aging. > > > > Amd-pstate driver utilizes the functions and data structures provided > > by the ITMT architecture to enable the scheduler to favor scheduling > > on cores which can be get a higher frequency with lower voltage. > > We call it amd-pstate preferred core. > > > > Here sched_set_itmt_core_prio() is called to set priorities and > > sched_set_itmt_support() is called to enable ITMT feature. > > Amd-pstate driver uses the highest performance value to indicate the > > priority of CPU. The higher value has a higher priority. > > > > Amd-pstate driver will provide an initial core ordering at boot time. > > It relies on the CPPC interface to communicate the core ranking to the > > operating system and scheduler to make sure that OS is choosing the > > cores with highest performance firstly for scheduling the process. > > When amd-pstate driver receives a message with the highest performance > > change, it will update the core ranking. > > > > Changes form V7->V8: > > - all: > > - - pick up Review-By flag added by Mario and Ray. > > - cpufreq: amd-pstate: > > - - use hw_prefcore embeds into cpudata structure. > > - - delete preferred core init from cpu online/off. > > Could you please let me know if this change means a fix for the report I've > sent previously? [1] > [Meng, Li (Jassmine)] Yes. I have deleted online handle function of amd pstate driver. It doesn't re-initialize preferred core. This online function will set incorrect des perf value. > Would you also be able to Cc me on the next iteration of this patchset? [Meng, Li (Jassmine)] OK. > > Thank you! > > [1] https://lore.kernel.org/lkml/5973628.lOV4Wx5bFT@xxxxxxxxxxxxxx/ > > > > > Changes form V6->V7: > > - x86: > > - - Modify kconfig about X86_AMD_PSTATE. > > - cpufreq: amd-pstate: > > - - modify incorrect comments about scheduler_work(). > > - - convert highest_perf data type. > > - - modify preferred core init when cpu init and online. > > - acpi: cppc: > > - - modify link of CPPC highest performance. > > - cpufreq: > > - - modify link of CPPC highest performance changed. > > > > Changes form V5->V6: > > - cpufreq: amd-pstate: > > - - modify the wrong tag order. > > - - modify warning about hw_prefcore sysfs attribute. > > - - delete duplicate comments. > > - - modify the variable name cppc_highest_perf to prefcore_ranking. > > - - modify judgment conditions for setting highest_perf. > > - - modify sysfs attribute for CPPC highest perf to pr_debug message. > > - Documentation: amd-pstate: > > - - modify warning: title underline too short. > > > > Changes form V4->V5: > > - cpufreq: amd-pstate: > > - - modify sysfs attribute for CPPC highest perf. > > - - modify warning about comments > > - - rebase linux-next > > - cpufreq: > > - - Moidfy warning about function declarations. > > - Documentation: amd-pstate: > > - - align with ``amd-pstat`` > > > > Changes form V3->V4: > > - Documentation: amd-pstate: > > - - Modify inappropriate descriptions. > > > > Changes form V2->V3: > > - x86: > > - - Modify kconfig and description. > > - cpufreq: amd-pstate: > > - - Add Co-developed-by tag in commit message. > > - cpufreq: > > - - Modify commit message. > > - Documentation: amd-pstate: > > - - Modify inappropriate descriptions. > > > > Changes form V1->V2: > > - acpi: cppc: > > - - Add reference link. > > - cpufreq: > > - - Moidfy link error. > > - cpufreq: amd-pstate: > > - - Init the priorities of all online CPUs > > - - Use a single variable to represent the status of preferred core. > > - Documentation: > > - - Default enabled preferred core. > > - Documentation: amd-pstate: > > - - Modify inappropriate descriptions. > > - - Default enabled preferred core. > > - - Use a single variable to represent the status of preferred core. > > > > Meng Li (7): > > x86: Drop CPU_SUP_INTEL from SCHED_MC_PRIO for the expansion. > > acpi: cppc: Add get the highest performance cppc control > > cpufreq: amd-pstate: Enable amd-pstate preferred core supporting. > > cpufreq: Add a notification message that the highest perf has changed > > cpufreq: amd-pstate: Update amd-pstate preferred core ranking > > dynamically > > Documentation: amd-pstate: introduce amd-pstate preferred core > > Documentation: introduce amd-pstate preferrd core mode kernel > command > > line options > > > > .../admin-guide/kernel-parameters.txt | 5 + > > Documentation/admin-guide/pm/amd-pstate.rst | 59 +++++- > > arch/x86/Kconfig | 5 +- > > drivers/acpi/cppc_acpi.c | 13 ++ > > drivers/acpi/processor_driver.c | 6 + > > drivers/cpufreq/amd-pstate.c | 186 ++++++++++++++++-- > > drivers/cpufreq/cpufreq.c | 13 ++ > > include/acpi/cppc_acpi.h | 5 + > > include/linux/amd-pstate.h | 10 + > > include/linux/cpufreq.h | 5 + > > 10 files changed, 285 insertions(+), 22 deletions(-) > > > > > > > -- > Oleksandr Natalenko (post-factum)
