Date: Thu, 14 Mar 2024 09:11:14 +0000
From: "Yuan, Perry" <Perry.Yuan@....com>
To: "Shenoy, Gautham Ranjal" <gautham.shenoy@....com>
CC: "rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>, "Limonciello,
 Mario" <Mario.Limonciello@....com>, "viresh.kumar@...aro.org"
	<viresh.kumar@...aro.org>, "Huang, Ray" <Ray.Huang@....com>, "Petkov,
 Borislav" <Borislav.Petkov@....com>, "Deucher, Alexander"
	<Alexander.Deucher@....com>, "Huang, Shimmer" <Shimmer.Huang@....com>, "Du,
 Xiaojian" <Xiaojian.Du@....com>, "Meng, Li (Jassmine)" <Li.Meng@....com>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v4 1/7] cpufreq: amd-pstate: initialize new core precision
 boost state

[AMD Official Use Only - General]

> -----Original Message-----
> From: Shenoy, Gautham Ranjal <gautham.shenoy@....com>
> Sent: Thursday, March 14, 2024 5:05 PM
> To: Yuan, Perry <Perry.Yuan@....com>
> Cc: rafael.j.wysocki@...el.com; Limonciello, Mario
> <Mario.Limonciello@....com>; viresh.kumar@...aro.org; Huang, Ray
> <Ray.Huang@....com>; Petkov, Borislav <Borislav.Petkov@....com>;
> Deucher, Alexander <Alexander.Deucher@....com>; Huang, Shimmer
> <Shimmer.Huang@....com>; Du, Xiaojian <Xiaojian.Du@....com>; Meng,
> Li (Jassmine) <Li.Meng@....com>; linux-pm@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Subject: Re: [PATCH v4 1/7] cpufreq: amd-pstate: initialize new core precision
> boost state
>
> On Wed, Mar 13, 2024 at 06:04:38PM +0800, Perry Yuan wrote:
> > From: Perry Yuan <Perry.Yuan@....com>
> >
> > Add gloal global_params to represent current CPU Performance
> > Boost(cpb) state for cpu frequency scaling, both active and passive
> > modes all can support CPU cores frequency boosting control which is
> > based on the BIOS setting, while BIOS turn on the "Core Performance
> > Boost", it will allow OS control each core highest perf limitation from OS side.
> >
> > If core performance boost is disabled while a core is in a boosted
> > P-state, the core transitions to the highest performance non-boosted
> > P-state, that is the same as the nominal frequency limit.
> >
> > Reported-by: Artem S. Tashkinov" <aros@....com>
> > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931
> > Signed-off-by: Perry Yuan <Perry.Yuan@....com>
> > ---
> >  drivers/cpufreq/amd-pstate.c | 50 ++++++++++++------------------------
> >  include/linux/amd-pstate.h   | 14 ++++++++++
> >  2 files changed, 31 insertions(+), 33 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 2015c9fcc3c9..ef6381b48e76
> 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -67,6 +67,8 @@ static struct cpufreq_driver amd_pstate_epp_driver;
> > static int cppc_state = AMD_PSTATE_UNDEFINED;  static bool
> > cppc_enabled;  static bool amd_pstate_prefcore = true;
> > +struct amd_pstate_global_params amd_pstate_global_params;
> > +EXPORT_SYMBOL_GPL(amd_pstate_global_params);
> >
> >  /*
> >   * AMD Energy Preference Performance (EPP) @@ -676,43 +678,21 @@
> > static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
> >     return lowest_nonlinear_freq * 1000;  }
> >
> > -static int amd_pstate_set_boost(struct cpufreq_policy *policy, int
> > state)
> > +static int amd_pstate_boost_init(struct amd_cpudata *cpudata)
> >  {
> > -   struct amd_cpudata *cpudata = policy->driver_data;
> > +   u64 boost_val;
> >     int ret;
> >
> > -   if (!cpudata->boost_supported) {
> > -           pr_err("Boost mode is not supported by this processor or
> SBIOS\n");
> > -           return -EINVAL;
> > -   }
> > -
> > -   if (state)
> > -           policy->cpuinfo.max_freq = cpudata->max_freq;
> > -   else
> > -           policy->cpuinfo.max_freq = cpudata->nominal_freq;
> > -
> > -   policy->max = policy->cpuinfo.max_freq;
> > -
> > -   ret = freq_qos_update_request(&cpudata->req[1],
> > -                                 policy->cpuinfo.max_freq);
> > -   if (ret < 0)
> > +   ret = rdmsrl_on_cpu(cpudata->cpu, MSR_K7_HWCR, &boost_val);
> > +   if (ret) {
> > +           pr_err_once("failed to read initial CPU boost state!\n");
> >             return ret;
> > +   }
> >
> > -   return 0;
> > -}
> > -
> > -static void amd_pstate_boost_init(struct amd_cpudata *cpudata) -{
> > -   u32 highest_perf, nominal_perf;
> > -
> > -   highest_perf = READ_ONCE(cpudata->highest_perf);
> > -   nominal_perf = READ_ONCE(cpudata->nominal_perf);
> > -
> > -   if (highest_perf <= nominal_perf)
> > -           return;
> > +   amd_pstate_global_params.cpb_supported = !((boost_val >> 25) &
> 0x1);
>
> Can we move the definition of MSR_K7_HWCR_CPB_DIS from
> drivers/cpufreq/acpi-cpufreq.h to msr-index.h and use it here ?
> something like the following:

That's a brilliant idea!
Let me add a new patch to move it in next version.

Perry.


>
> ----------- x8---------------------------------------------------------------------
> diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-
> index.h
> index f1bd7b91b3c6..e5380cad903c 100644
> --- a/arch/x86/include/asm/msr-index.h
> +++ b/arch/x86/include/asm/msr-index.h
> @@ -736,6 +736,8 @@
>  #define MSR_K7_HWCR_IRPERF_EN
> BIT_ULL(MSR_K7_HWCR_IRPERF_EN_BIT)
>  #define MSR_K7_FID_VID_CTL             0xc0010041
>  #define MSR_K7_FID_VID_STATUS          0xc0010042
> +#define MSR_K7_HWCR_CPB_DIS_BIT                25
> +#define MSR_K7_HWCR_CPB_DIS
> BIT_ULL(MSR_K7_HWCR_CPB_DIS_BIT)
>
>  /* K6 MSRs */
>  #define MSR_K6_WHCR                    0xc0000082
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index 37f1cdf46d29..7089aca6cc0d 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -31,6 +31,7 @@
>  #include <acpi/cppc_acpi.h>
>
>  #include <asm/msr.h>
> +#include <asm/msr-index.h>
>  #include <asm/processor.h>
>  #include <asm/cpufeature.h>
>  #include <asm/cpu_device_id.h>
> @@ -50,8 +51,6 @@ enum {
>  #define AMD_MSR_RANGE          (0x7)
>  #define HYGON_MSR_RANGE                (0x7)
>
> -#define MSR_K7_HWCR_CPB_DIS    (1ULL << 25)
> -
>  struct acpi_cpufreq_data {
>         unsigned int resume;
>         unsigned int cpu_feature;
>
>
>
> The rest of the patch looks good to me.

Thank you for the review!


>
>
> --
> Thanks and Regards
> gautham.
>
>
> > +   amd_pstate_global_params.cpb_boost =
> > +amd_pstate_global_params.cpb_supported;
> >
> > -   cpudata->boost_supported = true;
> > -   current_pstate_driver->boost_enabled = true;
> > +   return ret;
> >  }
> >
> >  static void amd_perf_ctl_reset(unsigned int cpu) @@ -855,6 +835,9 @@
> > static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> >     if (ret)
> >             goto free_cpudata1;
> >
> > +   /* initialize cpu cores boot state */
> > +   amd_pstate_boost_init(cpudata);
> > +
> >     min_freq = amd_get_min_freq(cpudata);
> >     max_freq = amd_get_max_freq(cpudata);
> >     nominal_freq = amd_get_nominal_freq(cpudata); @@ -906,7 +889,6
> @@
> > static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> >
> >     policy->driver_data = cpudata;
> >
> > -   amd_pstate_boost_init(cpudata);
> >     if (!current_pstate_driver->adjust_perf)
> >             current_pstate_driver->adjust_perf =
> amd_pstate_adjust_perf;
> >
> > @@ -1317,6 +1299,9 @@ static int amd_pstate_epp_cpu_init(struct
> cpufreq_policy *policy)
> >     if (ret)
> >             goto free_cpudata1;
> >
> > +   /* initialize cpu cores boot state */
> > +   amd_pstate_boost_init(cpudata);
> > +
> >     min_freq = amd_get_min_freq(cpudata);
> >     max_freq = amd_get_max_freq(cpudata);
> >     nominal_freq = amd_get_nominal_freq(cpudata); @@ -1367,7
> +1352,6 @@
> > static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
> >                     return ret;
> >             WRITE_ONCE(cpudata->cppc_cap1_cached, value);
> >     }
> > -   amd_pstate_boost_init(cpudata);
> >
> >     return 0;
> >
> > diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> > index d21838835abd..c6e2a97913de 100644
> > --- a/include/linux/amd-pstate.h
> > +++ b/include/linux/amd-pstate.h
> > @@ -124,4 +124,18 @@ static const char * const
> amd_pstate_mode_string[] = {
> >     [AMD_PSTATE_GUIDED]      = "guided",
> >     NULL,
> >  };
> > +
> > +/**
> > + * struct amd_pstate_global_params - Global parameters, mostly tunable
> via sysfs.
> > + * @cpb_boost:             Whether or not to use boost CPU P-states.
> > + * @cpb_supported: Whether or not CPU boost P-states are available
> > + *                 based on the MSR_K7_HWCR bit[25] state
> > + */
> > +struct amd_pstate_global_params {
> > +   bool cpb_boost;
> > +   bool cpb_supported;
> > +};
> > +
> > +extern struct amd_pstate_global_params amd_pstate_global_params;
> > +
> >  #endif /* _LINUX_AMD_PSTATE_H */
> > --
> > 2.34.1
> >

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