[PATCH 02/12] cpufreq: amd-pstate: enable AMD Precision Boost mode switch

[PATCH 02/12] cpufreq: amd-pstate: enable AMD Precision Boost mode switch

[Perry Yuan]

Add support to switch AMD precision boost state to scale cpu max
frequency that will help to improve the processor throughput.

when set boost state to be enabled, user will need to execute below commands,
the CPU will reach absolute maximum performance level or the highest perf which
CPU physical support. This performance level may not be sustainable for
long durations, it will help to improve the IO workload tasks.

* turn on CPU boost state under root
  echo 1 > /sys/devices/system/cpu/cpufreq/boost

If user set boost off,the CPU can reach to the maximum sustained
performance level of the process, that level is the process can maintain
continously working and definitely it can save some power compared to
boost on mode.

* turn off CPU boost state under root
  echo 0 > /sys/devices/system/cpu/cpufreq/boost

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
---
 arch/x86/include/asm/msr-index.h |  2 ++
 drivers/cpufreq/amd-pstate.c     | 22 +++++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 869508de8269..b952fd6d6916 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -559,6 +559,8 @@
 #define AMD_CPPC_MIN_PERF(x)		(((x) & 0xff) << 8)
 #define AMD_CPPC_DES_PERF(x)		(((x) & 0xff) << 16)
 #define AMD_CPPC_ENERGY_PERF_PREF(x)	(((x) & 0xff) << 24)
+#define AMD_CPPC_PRECISION_BOOST_BIT	25
+#define AMD_CPPC_PRECISION_BOOST_ENABLED	BIT_ULL(AMD_CPPC_PRECISION_BOOST_BIT)
 
 /* AMD Performance Counter Global Status and Control MSRs */
 #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS	0xc0000300
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 9ac75c1cde9c..188e055e24a2 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -122,6 +122,7 @@ struct amd_cpudata {
 
 	u64 freq;
 	bool	boost_supported;
+	u64 	cppc_hw_conf_cached;
 };
 
 static inline int pstate_enable(bool enable)
@@ -438,18 +439,27 @@ static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
 {
 	struct amd_cpudata *cpudata = policy->driver_data;
 	int ret;
+	u64 value;
 
 	if (!cpudata->boost_supported) {
 		pr_err("Boost mode is not supported by this processor or SBIOS\n");
 		return -EINVAL;
 	}
 
-	if (state)
+	ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL, &value);
+	if (ret)
+		return ret;
+
+	if (state) {
+		value |= AMD_CPPC_PRECISION_BOOST_ENABLED;
 		policy->cpuinfo.max_freq = cpudata->max_freq;
-	else
+	} else {
+		value &= ~AMD_CPPC_PRECISION_BOOST_ENABLED;
 		policy->cpuinfo.max_freq = cpudata->nominal_freq;
-
+	}
 	policy->max = policy->cpuinfo.max_freq;
+	WRITE_ONCE(cpudata->cppc_hw_conf_cached, value);
+	wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL, value);
 
 	ret = freq_qos_update_request(&cpudata->req[1],
 				      policy->cpuinfo.max_freq);
@@ -478,6 +488,7 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
 	struct device *dev;
 	struct amd_cpudata *cpudata;
+	u64 value;
 
 	dev = get_cpu_device(policy->cpu);
 	if (!dev)
@@ -542,6 +553,11 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 
 	policy->driver_data = cpudata;
 
+	ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL, &value);
+	if (ret)
+		return ret;
+	WRITE_ONCE(cpudata->cppc_hw_conf_cached, value);
+
 	amd_pstate_boost_init(cpudata);
 
 	return 0;
-- 
2.25.1

Re: [PATCH 02/12] cpufreq: amd-pstate: enable AMD Precision Boost mode switch

[Nathan Fontenot]

On 7/7/22 11:55, Perry Yuan wrote:
> Add support to switch AMD precision boost state to scale cpu max
> frequency that will help to improve the processor throughput.
> 
> when set boost state to be enabled, user will need to execute below commands,
> the CPU will reach absolute maximum performance level or the highest perf which
> CPU physical support. This performance level may not be sustainable for
> long durations, it will help to improve the IO workload tasks.
> 
> * turn on CPU boost state under root
>   echo 1 > /sys/devices/system/cpu/cpufreq/boost
> 
> If user set boost off,the CPU can reach to the maximum sustained
> performance level of the process, that level is the process can maintain
> continously working and definitely it can save some power compared to
> boost on mode.
> 
> * turn off CPU boost state under root
>   echo 0 > /sys/devices/system/cpu/cpufreq/boost
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> ---
>  arch/x86/include/asm/msr-index.h |  2 ++
>  drivers/cpufreq/amd-pstate.c     | 22 +++++++++++++++++++---
>  2 files changed, 21 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
> index 869508de8269..b952fd6d6916 100644
> --- a/arch/x86/include/asm/msr-index.h
> +++ b/arch/x86/include/asm/msr-index.h
> @@ -559,6 +559,8 @@
>  #define AMD_CPPC_MIN_PERF(x)		(((x) & 0xff) << 8)
>  #define AMD_CPPC_DES_PERF(x)		(((x) & 0xff) << 16)
>  #define AMD_CPPC_ENERGY_PERF_PREF(x)	(((x) & 0xff) << 24)
> +#define AMD_CPPC_PRECISION_BOOST_BIT	25
> +#define AMD_CPPC_PRECISION_BOOST_ENABLED	BIT_ULL(AMD_CPPC_PRECISION_BOOST_BIT)
>  
>  /* AMD Performance Counter Global Status and Control MSRs */
>  #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS	0xc0000300
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 9ac75c1cde9c..188e055e24a2 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -122,6 +122,7 @@ struct amd_cpudata {
>  
>  	u64 freq;
>  	bool	boost_supported;
> +	u64 	cppc_hw_conf_cached;

The MSR value is cached but I don't see that the cached value is used anywhere. Perhaps
I missed it in one of the other patches. Does this need to be cached?

-Nathan

>  };
>  
>  static inline int pstate_enable(bool enable)
> @@ -438,18 +439,27 @@ static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
>  {
>  	struct amd_cpudata *cpudata = policy->driver_data;
>  	int ret;
> +	u64 value;
>  
>  	if (!cpudata->boost_supported) {
>  		pr_err("Boost mode is not supported by this processor or SBIOS\n");
>  		return -EINVAL;
>  	}
>  
> -	if (state)
> +	ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL, &value);
> +	if (ret)
> +		return ret;
> +
> +	if (state) {
> +		value |= AMD_CPPC_PRECISION_BOOST_ENABLED;
>  		policy->cpuinfo.max_freq = cpudata->max_freq;
> -	else
> +	} else {
> +		value &= ~AMD_CPPC_PRECISION_BOOST_ENABLED;
>  		policy->cpuinfo.max_freq = cpudata->nominal_freq;
> -
> +	}
>  	policy->max = policy->cpuinfo.max_freq;
> +	WRITE_ONCE(cpudata->cppc_hw_conf_cached, value);
> +	wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL, value);
>  
>  	ret = freq_qos_update_request(&cpudata->req[1],
>  				      policy->cpuinfo.max_freq);
> @@ -478,6 +488,7 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
>  	struct device *dev;
>  	struct amd_cpudata *cpudata;
> +	u64 value;
>  
>  	dev = get_cpu_device(policy->cpu);
>  	if (!dev)
> @@ -542,6 +553,11 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  
>  	policy->driver_data = cpudata;
>  
> +	ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL, &value);
> +	if (ret)
> +		return ret;
> +	WRITE_ONCE(cpudata->cppc_hw_conf_cached, value);
> +
>  	amd_pstate_boost_init(cpudata);
>  
>  	return 0;

RE: [PATCH 02/12] cpufreq: amd-pstate: enable AMD Precision Boost mode switch

[Yuan, Perry]

[AMD Official Use Only - General]

Hi Nathan:

> -----Original Message-----
> From: Fontenot, Nathan <Nathan.Fontenot@amd.com>
> Sent: Friday, July 8, 2022 3:32 AM
> To: Yuan, Perry <Perry.Yuan@amd.com>; rafael.j.wysocki@intel.com;
> viresh.kumar@linaro.org; Huang, Ray <Ray.Huang@amd.com>; Thomas
> Gleixner <tglx@linutronix.de>; Ingo Molnar <mingo@redhat.com>; Borislav
> Petkov <bp@alien8.de>; Dave Hansen <dave.hansen@linux.intel.com>;
> x86@kernel.org; H. Peter Anvin <hpa@zytor.com>; Rafael J. Wysocki
> <rafael@kernel.org>; Peter Zijlstra <peterz@infradead.org>; Adrian Hunter
> <adrian.hunter@intel.com>; Pawan Gupta
> <pawan.kumar.gupta@linux.intel.com>; Alexander Shishkin
> <alexander.shishkin@linux.intel.com>; Tony Luck <tony.luck@intel.com>;
> Stephane Eranian <eranian@google.com>; Ricardo Neri <ricardo.neri-
> calderon@linux.intel.com>; linux-kernel@vger.kernel.org; linux-
> pm@vger.kernel.org
> Cc: Sharma, Deepak <Deepak.Sharma@amd.com>; Limonciello, Mario
> <Mario.Limonciello@amd.com>; Fontenot, Nathan
> <Nathan.Fontenot@amd.com>; Deucher, Alexander
> <Alexander.Deucher@amd.com>; Su, Jinzhou (Joe) <Jinzhou.Su@amd.com>;
> Huang, Shimmer <Shimmer.Huang@amd.com>; Du, Xiaojian
> <Xiaojian.Du@amd.com>; Meng, Li (Jassmine) <Li.Meng@amd.com>
> Subject: Re: [PATCH 02/12] cpufreq: amd-pstate: enable AMD Precision
> Boost mode switch
> 
> On 7/7/22 11:55, Perry Yuan wrote:
> > Add support to switch AMD precision boost state to scale cpu max
> > frequency that will help to improve the processor throughput.
> >
> > when set boost state to be enabled, user will need to execute below
> > commands, the CPU will reach absolute maximum performance level or
> the
> > highest perf which CPU physical support. This performance level may
> > not be sustainable for long durations, it will help to improve the IO
> workload tasks.
> >
> > * turn on CPU boost state under root
> >   echo 1 > /sys/devices/system/cpu/cpufreq/boost
> >
> > If user set boost off,the CPU can reach to the maximum sustained
> > performance level of the process, that level is the process can
> > maintain continously working and definitely it can save some power
> > compared to boost on mode.
> >
> > * turn off CPU boost state under root
> >   echo 0 > /sys/devices/system/cpu/cpufreq/boost
> >
> > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> > ---
> >  arch/x86/include/asm/msr-index.h |  2 ++
> >  drivers/cpufreq/amd-pstate.c     | 22 +++++++++++++++++++---
> >  2 files changed, 21 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/msr-index.h
> > b/arch/x86/include/asm/msr-index.h
> > index 869508de8269..b952fd6d6916 100644
> > --- a/arch/x86/include/asm/msr-index.h
> > +++ b/arch/x86/include/asm/msr-index.h
> > @@ -559,6 +559,8 @@
> >  #define AMD_CPPC_MIN_PERF(x)		(((x) & 0xff) << 8)
> >  #define AMD_CPPC_DES_PERF(x)		(((x) & 0xff) << 16)
> >  #define AMD_CPPC_ENERGY_PERF_PREF(x)	(((x) & 0xff) << 24)
> > +#define AMD_CPPC_PRECISION_BOOST_BIT	25
> > +#define AMD_CPPC_PRECISION_BOOST_ENABLED
> 	BIT_ULL(AMD_CPPC_PRECISION_BOOST_BIT)
> >
> >  /* AMD Performance Counter Global Status and Control MSRs */
> >  #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS	0xc0000300
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 9ac75c1cde9c..188e055e24a2
> 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -122,6 +122,7 @@ struct amd_cpudata {
> >
> >  	u64 freq;
> >  	bool	boost_supported;
> > +	u64 	cppc_hw_conf_cached;
> 
> The MSR value is cached but I don't see that the cached value is used
> anywhere. Perhaps I missed it in one of the other patches. Does this need
> to be cached?
> 
> -Nathan

The bit value will be used in the coming CPPC EPP patches to check if the CPU precision boost bit is enabled.
I early added this prefetching code as a preparing code.  

Perry.

> 
> >  };
> >
> >  static inline int pstate_enable(bool enable) @@ -438,18 +439,27 @@
> > static int amd_pstate_set_boost(struct cpufreq_policy *policy, int
> > state)  {
> >  	struct amd_cpudata *cpudata = policy->driver_data;
> >  	int ret;
> > +	u64 value;
> >
> >  	if (!cpudata->boost_supported) {
> >  		pr_err("Boost mode is not supported by this processor or
> SBIOS\n");
> >  		return -EINVAL;
> >  	}
> >
> > -	if (state)
> > +	ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL,
> &value);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (state) {
> > +		value |= AMD_CPPC_PRECISION_BOOST_ENABLED;
> >  		policy->cpuinfo.max_freq = cpudata->max_freq;
> > -	else
> > +	} else {
> > +		value &= ~AMD_CPPC_PRECISION_BOOST_ENABLED;
> >  		policy->cpuinfo.max_freq = cpudata->nominal_freq;
> > -
> > +	}
> >  	policy->max = policy->cpuinfo.max_freq;
> > +	WRITE_ONCE(cpudata->cppc_hw_conf_cached, value);
> > +	wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL, value);
> >
> >  	ret = freq_qos_update_request(&cpudata->req[1],
> >  				      policy->cpuinfo.max_freq);
> > @@ -478,6 +488,7 @@ static int amd_pstate_cpu_init(struct
> cpufreq_policy *policy)
> >  	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
> >  	struct device *dev;
> >  	struct amd_cpudata *cpudata;
> > +	u64 value;
> >
> >  	dev = get_cpu_device(policy->cpu);
> >  	if (!dev)
> > @@ -542,6 +553,11 @@ static int amd_pstate_cpu_init(struct
> > cpufreq_policy *policy)
> >
> >  	policy->driver_data = cpudata;
> >
> > +	ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL,
> &value);
> > +	if (ret)
> > +		return ret;
> > +	WRITE_ONCE(cpudata->cppc_hw_conf_cached, value);
> > +
> >  	amd_pstate_boost_init(cpudata);
> >
> >  	return 0;