[AMD Official Use Only - General] Hi Rafael:
> -----Original Message----- > From: Meng, Li (Jassmine) > Sent: Tuesday, December 26, 2023 4:27 PM > To: Rafael J. Wysocki <[email protected]> > Cc: Rafael J . Wysocki <[email protected]>; Huang, Ray > <[email protected]>; [email protected]; linux- > [email protected]; [email protected]; [email protected]; Shuah > Khan <[email protected]>; [email protected]; > Fontenot, Nathan <[email protected]>; Sharma, Deepak > <[email protected]>; Deucher, Alexander > <[email protected]>; Limonciello, Mario > <[email protected]>; Huang, Shimmer > <[email protected]>; Yuan, Perry <[email protected]>; Du, > Xiaojian <[email protected]>; Viresh Kumar <[email protected]>; > Borislav Petkov <[email protected]>; Oleksandr Natalenko > <[email protected]> > Subject: RE: [PATCH V12 4/7] cpufreq: Add a notification message that the > highest perf has changed > > Hi Rafael: > > > -----Original Message----- > > From: Rafael J. Wysocki <[email protected]> > > Sent: Tuesday, December 12, 2023 9:44 PM > > To: Meng, Li (Jassmine) <[email protected]> > > Cc: Rafael J . Wysocki <[email protected]>; Huang, Ray > > <[email protected]>; [email protected]; linux- > > [email protected]; [email protected]; [email protected]; > > Shuah Khan <[email protected]>; > > [email protected]; Fontenot, Nathan > > <[email protected]>; Sharma, Deepak > <[email protected]>; > > Deucher, Alexander <[email protected]>; Limonciello, Mario > > <[email protected]>; Huang, Shimmer > <[email protected]>; > > Yuan, Perry <[email protected]>; Du, Xiaojian > <[email protected]>; > > Viresh Kumar <[email protected]>; Borislav Petkov > > <[email protected]>; Oleksandr Natalenko <[email protected]> > > Subject: Re: [PATCH V12 4/7] cpufreq: Add a notification message that > > the highest perf has changed > > > > Caution: This message originated from an External Source. Use proper > > caution when opening attachments, clicking links, or responding. > > > > > > On Wed, Dec 6, 2023 at 10:13 PM Rafael J. Wysocki <[email protected]> > > wrote: > > > > > > On Wed, Dec 6, 2023 at 9:58 PM Rafael J. Wysocki <[email protected]> > > wrote: > > > > > > > > On Tue, Dec 5, 2023 at 7:38 AM Meng Li <[email protected]> wrote: > > > > > > > > > > ACPI 6.5 section 8.4.6.1.1.1 specifies that Notify event 0x85 > > > > > can be emmitted to cause the the OSPM to re-evaluate the highest > > > > > performance > > > > > > > > Typos above. Given the number of iterations of this patch, this > > > > is kind of disappointing. > > > > > > > > > register. Add support for this event. > > > > > > > > Also it would be nice to describe how this is supposed to work at > > > > least roughly, so it is not necessary to reverse-engineer the > > > > patch to find out that. > > > > > > > > > Tested-by: Oleksandr Natalenko <[email protected]> > > > > > Reviewed-by: Mario Limonciello <[email protected]> > > > > > Reviewed-by: Huang Rui <[email protected]> > > > > > Reviewed-by: Perry Yuan <[email protected]> > > > > > Signed-off-by: Meng Li <[email protected]> > > > > > Link: > > > > > > > https://uefi.org/specs/ACPI/6.5/05_ACPI_Software_Programming_Model > > > > > .html#processor-device-notification-values > > > > > --- > > > > > drivers/acpi/processor_driver.c | 6 ++++++ > > > > > drivers/cpufreq/cpufreq.c | 13 +++++++++++++ > > > > > include/linux/cpufreq.h | 5 +++++ > > > > > 3 files changed, 24 insertions(+) > > > > > > > > > > diff --git a/drivers/acpi/processor_driver.c > > > > > b/drivers/acpi/processor_driver.c index > > > > > 4bd16b3f0781..29b2fb68a35d > > > > > 100644 > > > > > --- a/drivers/acpi/processor_driver.c > > > > > +++ b/drivers/acpi/processor_driver.c > > > > > @@ -27,6 +27,7 @@ > > > > > #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80 > > > > > #define ACPI_PROCESSOR_NOTIFY_POWER 0x81 > > > > > #define ACPI_PROCESSOR_NOTIFY_THROTTLING 0x82 > > > > > +#define ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED > 0x85 > > > > > > > > > > MODULE_AUTHOR("Paul Diefenbaugh"); > > MODULE_DESCRIPTION("ACPI > > > > > Processor Driver"); @@ -83,6 +84,11 @@ static void > > > > > acpi_processor_notify(acpi_handle handle, u32 event, void *data) > > > > > > > > > > acpi_bus_generate_netlink_event(device->pnp.device_class, > > > > > > > > > > dev_name(&device->dev), event, 0); > > > > > break; > > > > > + case ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED: > > > > > + cpufreq_update_highest_perf(pr->id); > > > > > > > > And the design appears to be a bit ad-hoc here. > > > > > > > > Because why does it have anything to do with cpufreq? > > > > > > Well, clearly, cpufreq can be affected by this, but why would it be > > > not affected the same way as in the > > ACPI_PROCESSOR_NOTIFY_PERFORMANCE > > > case? > > > > > > That is, why isn't cpufreq_update_limits() the right thing to do? > > > > Seriously, I'm not going to apply this patch so long as my comments > > above are not addressed. > [Meng, Li (Jassmine)] > Sorry for the delayed reply to the email. > BIOS/AGESA is responsible to issue the Notify 0x85 to OS that the preferred > core has changed. > It will only affect the ranking of the preferred core, not the impact policy > limits. > AMD P-state driver will set the priority of the cores based on the preferred > core ranking, and prioritize selecting higher priority core to run the task. [Meng, Li (Jassmine)] From ACPI v6.5, Table 5.197 Processor Device Notification Values: Hex value Description 0x80 Performance Present Capabilities Changed. Used to notify OSPM that the number of supported processor performance states has changed. This notification causes OSPM to re-evaluate the _PPC object. See Section 8.4.5.3 for more information. 0x85 Highest Performance Changed. Used to notify OSPM that the value of the CPPC Highest Performance Register has changed. I think they are different notify events, so they need different functions to handle these events. Also see: https://uefi.org/specs/ACPI/6.5/05_ACPI_Software_Programming_Model.html#processor-device-notification-values
