RE: [PATCH V5 4/7] cpufreq: Add a notification message that the highest perf has changed

From: "Meng, Li (Jassmine)" <Li.Meng@amd.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	"Huang, Ray" <Ray.Huang@amd.com>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
	Shuah Khan <skhan@linuxfoundation.org>,
	"linux-kselftest@vger.kernel.org"
	<linux-kselftest@vger.kernel.org>,
	"Fontenot, Nathan" <Nathan.Fontenot@amd.com>,
	"Sharma, Deepak" <Deepak.Sharma@amd.com>,
	"Deucher, Alexander" <Alexander.Deucher@amd.com>,
	"Limonciello, Mario" <Mario.Limonciello@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>
Subject: RE: [PATCH V5 4/7] cpufreq: Add a notification message that the highest perf has changed
Date: Mon, 11 Sep 2023 08:43:59 +0000	[thread overview]
Message-ID: <DM4PR12MB63511F8BB2B229120DC8D9AFF7F2A@DM4PR12MB6351.namprd12.prod.outlook.com> (raw)
In-Reply-To: <20230908132402.GH19320@noisy.programming.kicks-ass.net>

[AMD Official Use Only - General]

Hi Peter:

> -----Original Message-----
> From: Peter Zijlstra <peterz@infradead.org>
> Sent: Friday, September 8, 2023 9:24 PM
> To: Meng, Li (Jassmine) <Li.Meng@amd.com>
> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>; Huang, Ray
> <Ray.Huang@amd.com>; 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>; Limonciello, Mario
> <Mario.Limonciello@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>
> Subject: Re: [PATCH V5 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 Tue, Sep 05, 2023 at 09:51:13AM +0800, Meng Li 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
> > register. Add support for this event.
> >
> > Signed-off-by: Meng Li <li.meng@amd.com>
> > Link:
> > https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control
> > .html?highlight=cppc#cpc-continuous-performance-control
> > ---
> >  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);
> > +             acpi_bus_generate_netlink_event(device->pnp.device_class,
> > +                                               dev_name(&device->dev), event, 0);
> > +             break;
> >       default:
> >               acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
> >               break;
>
> I've obviously not read the link, but the above seems to suggest that every
> CPU that has its limits changed gets the 'interrupt' ?
[Meng, Li (Jassmine)]
Yes.
I will modify the link to https://uefi.org/specs/ACPI/6.5/05_ACPI_Software_Programming_Model.html#processor-device-notification-values