[PATCH V3 0/7] AMD Pstate Preferred Core

[PATCH V3 0/7] AMD Pstate Preferred Core

[Meng Li]

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 Preferrred 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 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   |  53 ++++++
 arch/x86/Kconfig                              |   5 +-
 drivers/acpi/cppc_acpi.c                      |  13 ++
 drivers/acpi/processor_driver.c               |   6 +
 drivers/cpufreq/amd-pstate.c                  | 152 ++++++++++++++++--
 drivers/cpufreq/cpufreq.c                     |  13 ++
 include/acpi/cppc_acpi.h                      |   5 +
 include/linux/amd-pstate.h                    |   1 +
 include/linux/cpufreq.h                       |   4 +
 10 files changed, 239 insertions(+), 18 deletions(-)

-- 
2.34.1

[PATCH V3 1/7] x86: Drop CPU_SUP_INTEL from SCHED_MC_PRIO for the expansion.

[Meng Li]

AMD Pstate driver also uses SCHED_MC_PRIO, so decouple the requirement
of CPU_SUP_INTEL from the dependencies to allow compilation in kernels
without Intel CPU support.

Signed-off-by: Meng Li <li.meng@amd.com>
---
 arch/x86/Kconfig | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e36261b4ea14..16df141bd8a2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1052,8 +1052,9 @@ config SCHED_MC
 
 config SCHED_MC_PRIO
 	bool "CPU core priorities scheduler support"
-	depends on SCHED_MC && CPU_SUP_INTEL
-	select X86_INTEL_PSTATE
+	depends on SCHED_MC
+	select X86_INTEL_PSTATE if CPU_SUP_INTEL
+	select X86_AMD_PSTATE if CPU_SUP_AMD
 	select CPU_FREQ
 	default y
 	help
-- 
2.34.1

[PATCH V3 2/7] acpi: cppc: Add get the highest performance cppc control

[Meng Li]

Add support for getting the highest performance to the
generic CPPC driver. This enables downstream drivers
such as amd-pstate to discover and use these values.

Please refer to the ACPI_Spec for details on continuous
performance control of CPPC.

Signed-off-by: Meng Li <li.meng@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html?highlight=cppc#cpc-continuous-performance-control
---
 drivers/acpi/cppc_acpi.c | 13 +++++++++++++
 include/acpi/cppc_acpi.h |  5 +++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 7ff269a78c20..ad388a0e8484 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1154,6 +1154,19 @@ int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
 	return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
 }
 
+/**
+ * cppc_get_highest_perf - Get the highest performance register value.
+ * @cpunum: CPU from which to get highest performance.
+ * @highest_perf: Return address.
+ *
+ * Return: 0 for success, -EIO otherwise.
+ */
+int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
+{
+	return cppc_get_perf(cpunum, HIGHEST_PERF, highest_perf);
+}
+EXPORT_SYMBOL_GPL(cppc_get_highest_perf);
+
 /**
  * cppc_get_epp_perf - Get the epp register value.
  * @cpunum: CPU from which to get epp preference value.
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 6126c977ece0..c0b69ffe7bdb 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -139,6 +139,7 @@ struct cppc_cpudata {
 #ifdef CONFIG_ACPI_CPPC_LIB
 extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
 extern int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf);
+extern int cppc_get_highest_perf(int cpunum, u64 *highest_perf);
 extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
 extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
 extern int cppc_set_enable(int cpu, bool enable);
@@ -165,6 +166,10 @@ static inline int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
 {
 	return -ENOTSUPP;
 }
+static inline int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
+{
+	return -ENOTSUPP;
+}
 static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 {
 	return -ENOTSUPP;
-- 
2.34.1

Re: [PATCH V3 2/7] acpi: cppc: Add get the highest performance cppc control

[Wyes Karny]

On 24 Aug 10:12, Meng Li wrote:
> Add support for getting the highest performance to the
> generic CPPC driver. This enables downstream drivers
> such as amd-pstate to discover and use these values.
> 
> Please refer to the ACPI_Spec for details on continuous
> performance control of CPPC.
> 
> Signed-off-by: Meng Li <li.meng@amd.com>
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>

> Link: https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html?highlight=cppc#cpc-continuous-performance-control
> ---
>  drivers/acpi/cppc_acpi.c | 13 +++++++++++++
>  include/acpi/cppc_acpi.h |  5 +++++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 7ff269a78c20..ad388a0e8484 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -1154,6 +1154,19 @@ int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
>  	return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
>  }
>  
> +/**
> + * cppc_get_highest_perf - Get the highest performance register value.
> + * @cpunum: CPU from which to get highest performance.
> + * @highest_perf: Return address.
> + *
> + * Return: 0 for success, -EIO otherwise.
> + */
> +int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
> +{
> +	return cppc_get_perf(cpunum, HIGHEST_PERF, highest_perf);
> +}
> +EXPORT_SYMBOL_GPL(cppc_get_highest_perf);
> +
>  /**
>   * cppc_get_epp_perf - Get the epp register value.
>   * @cpunum: CPU from which to get epp preference value.
> diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
> index 6126c977ece0..c0b69ffe7bdb 100644
> --- a/include/acpi/cppc_acpi.h
> +++ b/include/acpi/cppc_acpi.h
> @@ -139,6 +139,7 @@ struct cppc_cpudata {
>  #ifdef CONFIG_ACPI_CPPC_LIB
>  extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
>  extern int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf);
> +extern int cppc_get_highest_perf(int cpunum, u64 *highest_perf);
>  extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
>  extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
>  extern int cppc_set_enable(int cpu, bool enable);
> @@ -165,6 +166,10 @@ static inline int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
>  {
>  	return -ENOTSUPP;
>  }
> +static inline int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
> +{
> +	return -ENOTSUPP;
> +}
>  static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
>  {
>  	return -ENOTSUPP;
> -- 
> 2.34.1
> 

Re: [PATCH V3 2/7] acpi: cppc: Add get the highest performance cppc control

[Wyes Karny]

On 24 Aug 10:12, Meng Li wrote:
> Add support for getting the highest performance to the
> generic CPPC driver. This enables downstream drivers
> such as amd-pstate to discover and use these values.
> 
> Please refer to the ACPI_Spec for details on continuous
> performance control of CPPC.
> 
> Signed-off-by: Meng Li <li.meng@amd.com>
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>

> Link: https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html?highlight=cppc#cpc-continuous-performance-control
> ---
>  drivers/acpi/cppc_acpi.c | 13 +++++++++++++
>  include/acpi/cppc_acpi.h |  5 +++++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 7ff269a78c20..ad388a0e8484 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -1154,6 +1154,19 @@ int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
>  	return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
>  }
>  
> +/**
> + * cppc_get_highest_perf - Get the highest performance register value.
> + * @cpunum: CPU from which to get highest performance.
> + * @highest_perf: Return address.
> + *
> + * Return: 0 for success, -EIO otherwise.
> + */
> +int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
> +{
> +	return cppc_get_perf(cpunum, HIGHEST_PERF, highest_perf);
> +}
> +EXPORT_SYMBOL_GPL(cppc_get_highest_perf);
> +
>  /**
>   * cppc_get_epp_perf - Get the epp register value.
>   * @cpunum: CPU from which to get epp preference value.
> diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
> index 6126c977ece0..c0b69ffe7bdb 100644
> --- a/include/acpi/cppc_acpi.h
> +++ b/include/acpi/cppc_acpi.h
> @@ -139,6 +139,7 @@ struct cppc_cpudata {
>  #ifdef CONFIG_ACPI_CPPC_LIB
>  extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
>  extern int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf);
> +extern int cppc_get_highest_perf(int cpunum, u64 *highest_perf);
>  extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
>  extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
>  extern int cppc_set_enable(int cpu, bool enable);
> @@ -165,6 +166,10 @@ static inline int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
>  {
>  	return -ENOTSUPP;
>  }
> +static inline int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
> +{
> +	return -ENOTSUPP;
> +}
>  static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
>  {
>  	return -ENOTSUPP;
> -- 
> 2.34.1
> 

[PATCH V3 3/7] cpufreq: amd-pstate: Enable AMD Pstate Preferred Core Supporting.

[Meng Li]

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 Preferrred 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.

The initial core rankings are set up by AMD Pstate when the
system boots.

Add device attribute for preferred core states.

Add one new early parameter `enable` to allow user to
enable the preferred core if the processor and power
firmware can support preferred core feature.

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Co-developed-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Meng Li <li.meng@amd.com>
Co-developed-by: Meng Li <li.meng@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 120 ++++++++++++++++++++++++++++++-----
 1 file changed, 104 insertions(+), 16 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 9a1e194d5cf8..d02305675f66 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -37,6 +37,7 @@
 #include <linux/uaccess.h>
 #include <linux/static_call.h>
 #include <linux/amd-pstate.h>
+#include <linux/topology.h>
 
 #include <acpi/processor.h>
 #include <acpi/cppc_acpi.h>
@@ -49,6 +50,8 @@
 
 #define AMD_PSTATE_TRANSITION_LATENCY	20000
 #define AMD_PSTATE_TRANSITION_DELAY	1000
+#define AMD_PSTATE_PREFCORE_THRESHOLD	166
+#define AMD_PSTATE_MAX_CPPC_PERF	255
 
 /*
  * TODO: We need more time to fine tune processors with shared memory solution
@@ -65,6 +68,9 @@ static struct cpufreq_driver amd_pstate_epp_driver;
 static int cppc_state = AMD_PSTATE_UNDEFINED;
 static bool cppc_enabled;
 
+/*Preferred Core featue is supported*/
+static bool prefcore = true;
+
 /*
  * AMD Energy Preference Performance (EPP)
  * The EPP is used in the CCLK DPM controller to drive
@@ -290,23 +296,21 @@ static inline int amd_pstate_enable(bool enable)
 static int pstate_init_perf(struct amd_cpudata *cpudata)
 {
 	u64 cap1;
-	u32 highest_perf;
 
 	int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
 				     &cap1);
 	if (ret)
 		return ret;
 
-	/*
-	 * TODO: Introduce AMD specific power feature.
-	 *
-	 * CPPC entry doesn't indicate the highest performance in some ASICs.
+	/* For platforms that do not support the preferred core feature, the
+	 * highest_pef may be configured with 166 or 255, to avoid max frequency
+	 * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1) value as
+	 * the default max perf.
 	 */
-	highest_perf = amd_get_highest_perf();
-	if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1))
-		highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
-
-	WRITE_ONCE(cpudata->highest_perf, highest_perf);
+	if (prefcore)
+		WRITE_ONCE(cpudata->highest_perf, AMD_PSTATE_PREFCORE_THRESHOLD);
+	else
+		WRITE_ONCE(cpudata->highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
 
 	WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));
 	WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
@@ -318,17 +322,15 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
 static int cppc_init_perf(struct amd_cpudata *cpudata)
 {
 	struct cppc_perf_caps cppc_perf;
-	u32 highest_perf;
 
 	int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
 	if (ret)
 		return ret;
 
-	highest_perf = amd_get_highest_perf();
-	if (highest_perf > cppc_perf.highest_perf)
-		highest_perf = cppc_perf.highest_perf;
-
-	WRITE_ONCE(cpudata->highest_perf, highest_perf);
+	if (prefcore)
+		WRITE_ONCE(cpudata->highest_perf, AMD_PSTATE_PREFCORE_THRESHOLD);
+	else
+		WRITE_ONCE(cpudata->highest_perf, cppc_perf.highest_perf);
 
 	WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
 	WRITE_ONCE(cpudata->lowest_nonlinear_perf,
@@ -676,6 +678,72 @@ static void amd_perf_ctl_reset(unsigned int cpu)
 	wrmsrl_on_cpu(cpu, MSR_AMD_PERF_CTL, 0);
 }
 
+/*
+ * Set AMD Pstate Preferred Core enable can't be done directly from cpufreq callbacks
+ * due to locking, so queue the work for later.
+ */
+static void amd_pstste_sched_prefcore_workfn(struct work_struct *work)
+{
+	sched_set_itmt_support();
+}
+static DECLARE_WORK(sched_prefcore_work, amd_pstste_sched_prefcore_workfn);
+
+/**
+ * Get the highest performance register value.
+ * @cpu: CPU from which to get highest performance.
+ * @highest_perf: Return address.
+ *
+ * Return: 0 for success, -EIO otherwise.
+ */
+static int amd_pstate_get_highest_perf(int cpu, u64 *highest_perf)
+{
+       int ret;
+
+       if (boot_cpu_has(X86_FEATURE_CPPC)) {
+               u64 cap1;
+
+               ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &cap1);
+               if (ret)
+                       return ret;
+               WRITE_ONCE(*highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
+       } else {
+               ret = cppc_get_highest_perf(cpu, highest_perf);
+       }
+
+       return (ret);
+}
+
+static void amd_pstate_init_prefcore(void)
+{
+	int cpu, ret;
+	u64 highest_perf;
+
+	if (!prefcore)
+		return;
+
+	for_each_online_cpu(cpu) {
+		ret = amd_pstate_get_highest_perf(cpu, &highest_perf);
+		if (ret)
+			break;
+
+		sched_set_itmt_core_prio(highest_perf, cpu);
+
+		/* check if CPPC preferred core feature is enabled*/
+		if (highest_perf == AMD_PSTATE_MAX_CPPC_PERF) {
+			prefcore = false;
+			return;
+		}
+	}
+
+	/*
+	 * This code can be run during CPU online under the
+	 * CPU hotplug locks, so sched_set_amd_prefcore_support()
+	 * cannot be called from here.  Queue up a work item
+	 * to invoke it.
+	 */
+	schedule_work(&sched_prefcore_work);
+}
+
 static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 {
 	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
@@ -1037,6 +1105,12 @@ static ssize_t status_store(struct device *a, struct device_attribute *b,
 	return ret < 0 ? ret : count;
 }
 
+static ssize_t prefcore_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%s\n", prefcore ? "enabled" : "disabled");
+}
+
 cpufreq_freq_attr_ro(amd_pstate_max_freq);
 cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
 
@@ -1044,6 +1118,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf);
 cpufreq_freq_attr_rw(energy_performance_preference);
 cpufreq_freq_attr_ro(energy_performance_available_preferences);
 static DEVICE_ATTR_RW(status);
+static DEVICE_ATTR_RO(prefcore);
 
 static struct freq_attr *amd_pstate_attr[] = {
 	&amd_pstate_max_freq,
@@ -1063,6 +1138,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
 
 static struct attribute *pstate_global_attributes[] = {
 	&dev_attr_status.attr,
+	&dev_attr_prefcore.attr,
 	NULL
 };
 
@@ -1506,6 +1582,8 @@ static int __init amd_pstate_init(void)
 		}
 	}
 
+	amd_pstate_init_prefcore();
+
 	return ret;
 
 global_attr_free:
@@ -1527,7 +1605,17 @@ static int __init amd_pstate_param(char *str)
 
 	return amd_pstate_set_driver(mode_idx);
 }
+
+static int __init amd_prefcore_param(char *str)
+{
+	if (!strcmp(str, "disable"))
+		prefcore = false;
+
+	return 0;
+}
+
 early_param("amd_pstate", amd_pstate_param);
+early_param("amd_prefcore", amd_prefcore_param);
 
 MODULE_AUTHOR("Huang Rui <ray.huang@amd.com>");
 MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver");
-- 
2.34.1

Re: [PATCH V3 3/7] cpufreq: amd-pstate: Enable AMD Pstate Preferred Core Supporting.

[Wyes Karny]

Hi Meng Li,

On 24 Aug 10:12, Meng Li wrote:
> 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 Preferrred 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.
> 
> The initial core rankings are set up by AMD Pstate when the
> system boots.
> 
> Add device attribute for preferred core states.
> 
> Add one new early parameter `enable` to allow user to
> enable the preferred core if the processor and power
> firmware can support preferred core feature.
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> Co-developed-by: Perry Yuan <Perry.Yuan@amd.com>
> Signed-off-by: Meng Li <li.meng@amd.com>
> Co-developed-by: Meng Li <li.meng@amd.com>
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
>  drivers/cpufreq/amd-pstate.c | 120 ++++++++++++++++++++++++++++++-----
>  1 file changed, 104 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 9a1e194d5cf8..d02305675f66 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -37,6 +37,7 @@
>  #include <linux/uaccess.h>
>  #include <linux/static_call.h>
>  #include <linux/amd-pstate.h>
> +#include <linux/topology.h>
>  
>  #include <acpi/processor.h>
>  #include <acpi/cppc_acpi.h>
> @@ -49,6 +50,8 @@
>  
>  #define AMD_PSTATE_TRANSITION_LATENCY	20000
>  #define AMD_PSTATE_TRANSITION_DELAY	1000
> +#define AMD_PSTATE_PREFCORE_THRESHOLD	166
> +#define AMD_PSTATE_MAX_CPPC_PERF	255
>  
>  /*
>   * TODO: We need more time to fine tune processors with shared memory solution
> @@ -65,6 +68,9 @@ static struct cpufreq_driver amd_pstate_epp_driver;
>  static int cppc_state = AMD_PSTATE_UNDEFINED;
>  static bool cppc_enabled;
>  
> +/*Preferred Core featue is supported*/
> +static bool prefcore = true;
> +
>  /*
>   * AMD Energy Preference Performance (EPP)
>   * The EPP is used in the CCLK DPM controller to drive
> @@ -290,23 +296,21 @@ static inline int amd_pstate_enable(bool enable)
>  static int pstate_init_perf(struct amd_cpudata *cpudata)
>  {
>  	u64 cap1;
> -	u32 highest_perf;
>  
>  	int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
>  				     &cap1);
>  	if (ret)
>  		return ret;
>  
> -	/*
> -	 * TODO: Introduce AMD specific power feature.
> -	 *
> -	 * CPPC entry doesn't indicate the highest performance in some ASICs.
> +	/* For platforms that do not support the preferred core feature, the
> +	 * highest_pef may be configured with 166 or 255, to avoid max frequency
> +	 * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1) value as
> +	 * the default max perf.
>  	 */
> -	highest_perf = amd_get_highest_perf();
> -	if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1))
> -		highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
> -
> -	WRITE_ONCE(cpudata->highest_perf, highest_perf);
> +	if (prefcore)
> +		WRITE_ONCE(cpudata->highest_perf, AMD_PSTATE_PREFCORE_THRESHOLD);
> +	else
> +		WRITE_ONCE(cpudata->highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));

Can we disable `preferred core` in HW? If not then when we disable
`preferred core` in software (via the cmd line param you have created),
HW still gives core ranking through highest perf register/MSR. So, we
have to filter the core ranking info form the highest perf register/MSR
and set cpudata->highest_perf accordingly. IMO we should have two
variables, one which indicated HW support and other one which indicates SW
overwrite. In this function we should be checking only HW support.

>  
>  	WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));
>  	WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
> @@ -318,17 +322,15 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
>  static int cppc_init_perf(struct amd_cpudata *cpudata)
>  {
>  	struct cppc_perf_caps cppc_perf;
> -	u32 highest_perf;
>  
>  	int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
>  	if (ret)
>  		return ret;
>  
> -	highest_perf = amd_get_highest_perf();
> -	if (highest_perf > cppc_perf.highest_perf)
> -		highest_perf = cppc_perf.highest_perf;
> -
> -	WRITE_ONCE(cpudata->highest_perf, highest_perf);
> +	if (prefcore)
> +		WRITE_ONCE(cpudata->highest_perf, AMD_PSTATE_PREFCORE_THRESHOLD);
> +	else
> +		WRITE_ONCE(cpudata->highest_perf, cppc_perf.highest_perf);

Here also we should be checking only HW support.

>  
>  	WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
>  	WRITE_ONCE(cpudata->lowest_nonlinear_perf,
> @@ -676,6 +678,72 @@ static void amd_perf_ctl_reset(unsigned int cpu)
>  	wrmsrl_on_cpu(cpu, MSR_AMD_PERF_CTL, 0);
>  }
>  
> +/*
> + * Set AMD Pstate Preferred Core enable can't be done directly from cpufreq callbacks
> + * due to locking, so queue the work for later.
> + */
> +static void amd_pstste_sched_prefcore_workfn(struct work_struct *work)
> +{
> +	sched_set_itmt_support();
> +}
> +static DECLARE_WORK(sched_prefcore_work, amd_pstste_sched_prefcore_workfn);
> +
> +/**
> + * Get the highest performance register value.
> + * @cpu: CPU from which to get highest performance.
> + * @highest_perf: Return address.
> + *
> + * Return: 0 for success, -EIO otherwise.
> + */
> +static int amd_pstate_get_highest_perf(int cpu, u64 *highest_perf)
> +{
> +       int ret;
> +
> +       if (boot_cpu_has(X86_FEATURE_CPPC)) {
> +               u64 cap1;
> +
> +               ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &cap1);
> +               if (ret)
> +                       return ret;
> +               WRITE_ONCE(*highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
> +       } else {
> +               ret = cppc_get_highest_perf(cpu, highest_perf);
> +       }
> +
> +       return (ret);
> +}
> +
> +static void amd_pstate_init_prefcore(void)
> +{
> +	int cpu, ret;
> +	u64 highest_perf;
> +
> +	if (!prefcore)
> +		return;
> +
> +	for_each_online_cpu(cpu) {
> +		ret = amd_pstate_get_highest_perf(cpu, &highest_perf);
> +		if (ret)
> +			break;
> +
> +		sched_set_itmt_core_prio(highest_perf, cpu);
> +
> +		/* check if CPPC preferred core feature is enabled*/
> +		if (highest_perf == AMD_PSTATE_MAX_CPPC_PERF) {
> +			prefcore = false;
> +			return;

255 is a valid core ranking right?

Thanks & Regards,
Wyes

> +		}
> +	}
> +
> +	/*
> +	 * This code can be run during CPU online under the
> +	 * CPU hotplug locks, so sched_set_amd_prefcore_support()
> +	 * cannot be called from here.  Queue up a work item
> +	 * to invoke it.
> +	 */
> +	schedule_work(&sched_prefcore_work);
> +}
> +
>  static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  {
>  	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
> @@ -1037,6 +1105,12 @@ static ssize_t status_store(struct device *a, struct device_attribute *b,
>  	return ret < 0 ? ret : count;
>  }
>  
> +static ssize_t prefcore_show(struct device *dev,
> +				   struct device_attribute *attr, char *buf)
> +{
> +	return sysfs_emit(buf, "%s\n", prefcore ? "enabled" : "disabled");
> +}
> +
>  cpufreq_freq_attr_ro(amd_pstate_max_freq);
>  cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>  
> @@ -1044,6 +1118,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf);
>  cpufreq_freq_attr_rw(energy_performance_preference);
>  cpufreq_freq_attr_ro(energy_performance_available_preferences);
>  static DEVICE_ATTR_RW(status);
> +static DEVICE_ATTR_RO(prefcore);
>  
>  static struct freq_attr *amd_pstate_attr[] = {
>  	&amd_pstate_max_freq,
> @@ -1063,6 +1138,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
>  
>  static struct attribute *pstate_global_attributes[] = {
>  	&dev_attr_status.attr,
> +	&dev_attr_prefcore.attr,
>  	NULL
>  };
>  
> @@ -1506,6 +1582,8 @@ static int __init amd_pstate_init(void)
>  		}
>  	}
>  
> +	amd_pstate_init_prefcore();
> +
>  	return ret;
>  
>  global_attr_free:
> @@ -1527,7 +1605,17 @@ static int __init amd_pstate_param(char *str)
>  
>  	return amd_pstate_set_driver(mode_idx);
>  }
> +
> +static int __init amd_prefcore_param(char *str)
> +{
> +	if (!strcmp(str, "disable"))
> +		prefcore = false;
> +
> +	return 0;
> +}
> +
>  early_param("amd_pstate", amd_pstate_param);
> +early_param("amd_prefcore", amd_prefcore_param);
>  
>  MODULE_AUTHOR("Huang Rui <ray.huang@amd.com>");
>  MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver");
> -- 
> 2.34.1
> 

RE: [PATCH V3 3/7] cpufreq: amd-pstate: Enable AMD Pstate Preferred Core Supporting.

[Meng, Li (Jassmine)]

[AMD Official Use Only - General]

Hello Wyes:

> -----Original Message-----
> From: Karny, Wyes <Wyes.Karny@amd.com>
> Sent: Thursday, August 24, 2023 2:48 PM
> To: Meng, Li (Jassmine) <Li.Meng@amd.com>
> Cc: Karny, Wyes <Wyes.Karny@amd.com>; 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 V3 3/7] cpufreq: amd-pstate: Enable AMD Pstate
> Preferred Core Supporting.
>
> Hi Meng Li,
>
> On 24 Aug 10:12, Meng Li wrote:
> > 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 Preferrred 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.
> >
> > The initial core rankings are set up by AMD Pstate when the system
> > boots.
> >
> > Add device attribute for preferred core states.
> >
> > Add one new early parameter `enable` to allow user to enable the
> > preferred core if the processor and power firmware can support
> > preferred core feature.
> >
> > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> > Co-developed-by: Perry Yuan <Perry.Yuan@amd.com>
> > Signed-off-by: Meng Li <li.meng@amd.com>
> > Co-developed-by: Meng Li <li.meng@amd.com>
> > Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
> > ---
> >  drivers/cpufreq/amd-pstate.c | 120
> > ++++++++++++++++++++++++++++++-----
> >  1 file changed, 104 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 9a1e194d5cf8..d02305675f66 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -37,6 +37,7 @@
> >  #include <linux/uaccess.h>
> >  #include <linux/static_call.h>
> >  #include <linux/amd-pstate.h>
> > +#include <linux/topology.h>
> >
> >  #include <acpi/processor.h>
> >  #include <acpi/cppc_acpi.h>
> > @@ -49,6 +50,8 @@
> >
> >  #define AMD_PSTATE_TRANSITION_LATENCY      20000
> >  #define AMD_PSTATE_TRANSITION_DELAY        1000
> > +#define AMD_PSTATE_PREFCORE_THRESHOLD      166
> > +#define AMD_PSTATE_MAX_CPPC_PERF   255
> >
> >  /*
> >   * TODO: We need more time to fine tune processors with shared memory
> > solution @@ -65,6 +68,9 @@ static struct cpufreq_driver
> > amd_pstate_epp_driver;  static int cppc_state =
> AMD_PSTATE_UNDEFINED;
> > static bool cppc_enabled;
> >
> > +/*Preferred Core featue is supported*/ static bool prefcore = true;
> > +
> >  /*
> >   * AMD Energy Preference Performance (EPP)
> >   * The EPP is used in the CCLK DPM controller to drive @@ -290,23
> > +296,21 @@ static inline int amd_pstate_enable(bool enable)  static
> > int pstate_init_perf(struct amd_cpudata *cpudata)  {
> >     u64 cap1;
> > -   u32 highest_perf;
> >
> >     int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
> >                                  &cap1);
> >     if (ret)
> >             return ret;
> >
> > -   /*
> > -    * TODO: Introduce AMD specific power feature.
> > -    *
> > -    * CPPC entry doesn't indicate the highest performance in some
> ASICs.
> > +   /* For platforms that do not support the preferred core feature, the
> > +    * highest_pef may be configured with 166 or 255, to avoid max
> frequency
> > +    * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1)
> value as
> > +    * the default max perf.
> >      */
> > -   highest_perf = amd_get_highest_perf();
> > -   if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1))
> > -           highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
> > -
> > -   WRITE_ONCE(cpudata->highest_perf, highest_perf);
> > +   if (prefcore)
> > +           WRITE_ONCE(cpudata->highest_perf,
> AMD_PSTATE_PREFCORE_THRESHOLD);
> > +   else
> > +           WRITE_ONCE(cpudata->highest_perf,
> AMD_CPPC_HIGHEST_PERF(cap1));
>
> Can we disable `preferred core` in HW? If not then when we disable
> `preferred core` in software (via the cmd line param you have created), HW
> still gives core ranking through highest perf register/MSR. So, we have to
> filter the core ranking info form the highest perf register/MSR and set
> cpudata->highest_perf accordingly. IMO we should have two variables, one
> which indicated HW support and other one which indicates SW overwrite. In
> this function we should be checking only HW support.
>
[Meng, Li (Jassmine)]
We use one variable 'prefcore' to check whether the `preferred core` is supported.
When either HW or SW does not support `preferred core`, it will be set to false.
When 'highest_perf' is 255, it indicates that HW does not support `preferred core`.

> >
> >     WRITE_ONCE(cpudata->nominal_perf,
> AMD_CPPC_NOMINAL_PERF(cap1));
> >     WRITE_ONCE(cpudata->lowest_nonlinear_perf,
> > AMD_CPPC_LOWNONLIN_PERF(cap1)); @@ -318,17 +322,15 @@ static int
> > pstate_init_perf(struct amd_cpudata *cpudata)  static int
> > cppc_init_perf(struct amd_cpudata *cpudata)  {
> >     struct cppc_perf_caps cppc_perf;
> > -   u32 highest_perf;
> >
> >     int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
> >     if (ret)
> >             return ret;
> >
> > -   highest_perf = amd_get_highest_perf();
> > -   if (highest_perf > cppc_perf.highest_perf)
> > -           highest_perf = cppc_perf.highest_perf;
> > -
> > -   WRITE_ONCE(cpudata->highest_perf, highest_perf);
> > +   if (prefcore)
> > +           WRITE_ONCE(cpudata->highest_perf,
> AMD_PSTATE_PREFCORE_THRESHOLD);
> > +   else
> > +           WRITE_ONCE(cpudata->highest_perf,
> cppc_perf.highest_perf);
>
> Here also we should be checking only HW support.
>
> >
> >     WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
> >     WRITE_ONCE(cpudata->lowest_nonlinear_perf,
> > @@ -676,6 +678,72 @@ static void amd_perf_ctl_reset(unsigned int cpu)
> >     wrmsrl_on_cpu(cpu, MSR_AMD_PERF_CTL, 0);  }
> >
> > +/*
> > + * Set AMD Pstate Preferred Core enable can't be done directly from
> > +cpufreq callbacks
> > + * due to locking, so queue the work for later.
> > + */
> > +static void amd_pstste_sched_prefcore_workfn(struct work_struct
> > +*work) {
> > +   sched_set_itmt_support();
> > +}
> > +static DECLARE_WORK(sched_prefcore_work,
> > +amd_pstste_sched_prefcore_workfn);
> > +
> > +/**
> > + * Get the highest performance register value.
> > + * @cpu: CPU from which to get highest performance.
> > + * @highest_perf: Return address.
> > + *
> > + * Return: 0 for success, -EIO otherwise.
> > + */
> > +static int amd_pstate_get_highest_perf(int cpu, u64 *highest_perf) {
> > +       int ret;
> > +
> > +       if (boot_cpu_has(X86_FEATURE_CPPC)) {
> > +               u64 cap1;
> > +
> > +               ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &cap1);
> > +               if (ret)
> > +                       return ret;
> > +               WRITE_ONCE(*highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
> > +       } else {
> > +               ret = cppc_get_highest_perf(cpu, highest_perf);
> > +       }
> > +
> > +       return (ret);
> > +}
> > +
> > +static void amd_pstate_init_prefcore(void) {
> > +   int cpu, ret;
> > +   u64 highest_perf;
> > +
> > +   if (!prefcore)
> > +           return;
> > +
> > +   for_each_online_cpu(cpu) {
> > +           ret = amd_pstate_get_highest_perf(cpu, &highest_perf);
> > +           if (ret)
> > +                   break;
> > +
> > +           sched_set_itmt_core_prio(highest_perf, cpu);
> > +
> > +           /* check if CPPC preferred core feature is enabled*/
> > +           if (highest_perf == AMD_PSTATE_MAX_CPPC_PERF) {
> > +                   prefcore = false;
> > +                   return;
>
> 255 is a valid core ranking right?
>
> Thanks & Regards,
> Wyes
>
> > +           }
> > +   }
> > +
> > +   /*
> > +    * This code can be run during CPU online under the
> > +    * CPU hotplug locks, so sched_set_amd_prefcore_support()
> > +    * cannot be called from here.  Queue up a work item
> > +    * to invoke it.
> > +    */
> > +   schedule_work(&sched_prefcore_work);
> > +}
> > +
> >  static int amd_pstate_cpu_init(struct cpufreq_policy *policy)  {
> >     int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
> @@
> > -1037,6 +1105,12 @@ static ssize_t status_store(struct device *a, struct
> device_attribute *b,
> >     return ret < 0 ? ret : count;
> >  }
> >
> > +static ssize_t prefcore_show(struct device *dev,
> > +                              struct device_attribute *attr, char *buf) {
> > +   return sysfs_emit(buf, "%s\n", prefcore ? "enabled" : "disabled"); }
> > +
> >  cpufreq_freq_attr_ro(amd_pstate_max_freq);
> >  cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
> >
> > @@ -1044,6 +1118,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> >  cpufreq_freq_attr_rw(energy_performance_preference);
> >  cpufreq_freq_attr_ro(energy_performance_available_preferences);
> >  static DEVICE_ATTR_RW(status);
> > +static DEVICE_ATTR_RO(prefcore);
> >
> >  static struct freq_attr *amd_pstate_attr[] = {
> >     &amd_pstate_max_freq,
> > @@ -1063,6 +1138,7 @@ static struct freq_attr *amd_pstate_epp_attr[] =
> > {
> >
> >  static struct attribute *pstate_global_attributes[] = {
> >     &dev_attr_status.attr,
> > +   &dev_attr_prefcore.attr,
> >     NULL
> >  };
> >
> > @@ -1506,6 +1582,8 @@ static int __init amd_pstate_init(void)
> >             }
> >     }
> >
> > +   amd_pstate_init_prefcore();
> > +
> >     return ret;
> >
> >  global_attr_free:
> > @@ -1527,7 +1605,17 @@ static int __init amd_pstate_param(char *str)
> >
> >     return amd_pstate_set_driver(mode_idx);  }
> > +
> > +static int __init amd_prefcore_param(char *str) {
> > +   if (!strcmp(str, "disable"))
> > +           prefcore = false;
> > +
> > +   return 0;
> > +}
> > +
> >  early_param("amd_pstate", amd_pstate_param);
> > +early_param("amd_prefcore", amd_prefcore_param);
> >
> >  MODULE_AUTHOR("Huang Rui <ray.huang@amd.com>");
> > MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver");
> > --
> > 2.34.1
> >

[PATCH V3 4/7] cpufreq: Add a notification message that the highest perf has changed

[Meng Li]

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         |  4 ++++
 3 files changed, 23 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;
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 50bbc969ffe5..842357abfae6 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2675,6 +2675,19 @@ void cpufreq_update_limits(unsigned int cpu)
 }
 EXPORT_SYMBOL_GPL(cpufreq_update_limits);
 
+/**
+ * cpufreq_update_highest_perf - Update highest performance for a given CPU.
+ * @cpu: CPU to update the highest performance for.
+ *
+ * Invoke the driver's ->update_highest_perf callback if present
+ */
+void cpufreq_update_highest_perf(unsigned int cpu)
+{
+	if (cpufreq_driver->update_highest_perf)
+		cpufreq_driver->update_highest_perf(cpu);
+}
+EXPORT_SYMBOL_GPL(cpufreq_update_highest_perf);
+
 /*********************************************************************
  *               BOOST						     *
  *********************************************************************/
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 9bf94ae08158..58106b3d9183 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -232,6 +232,7 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
 void refresh_frequency_limits(struct cpufreq_policy *policy);
 void cpufreq_update_policy(unsigned int cpu);
 void cpufreq_update_limits(unsigned int cpu);
+void cpufreq_update_highest_perf(unsigned int cpu);
 bool have_governor_per_policy(void);
 bool cpufreq_supports_freq_invariance(void);
 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
@@ -377,6 +378,9 @@ struct cpufreq_driver {
 	/* Called to update policy limits on firmware notifications. */
 	void		(*update_limits)(unsigned int cpu);
 
+	/* Called to update highest performance on firmware notifications. */
+	void		(*update_highest_perf)(unsigned int cpu);
+
 	/* optional */
 	int		(*bios_limit)(int cpu, unsigned int *limit);
 
-- 
2.34.1

Re: [PATCH V3 4/7] cpufreq: Add a notification message that the highest perf has changed

[Wyes Karny]

On 24 Aug 10:12, 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         |  4 ++++
>  3 files changed, 23 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;
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 50bbc969ffe5..842357abfae6 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2675,6 +2675,19 @@ void cpufreq_update_limits(unsigned int cpu)
>  }
>  EXPORT_SYMBOL_GPL(cpufreq_update_limits);
>  
> +/**
> + * cpufreq_update_highest_perf - Update highest performance for a given CPU.
> + * @cpu: CPU to update the highest performance for.
> + *
> + * Invoke the driver's ->update_highest_perf callback if present
> + */
> +void cpufreq_update_highest_perf(unsigned int cpu)
> +{
> +	if (cpufreq_driver->update_highest_perf)
> +		cpufreq_driver->update_highest_perf(cpu);
> +}
> +EXPORT_SYMBOL_GPL(cpufreq_update_highest_perf);
> +
>  /*********************************************************************
>   *               BOOST						     *
>   *********************************************************************/
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index 9bf94ae08158..58106b3d9183 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -232,6 +232,7 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
>  void refresh_frequency_limits(struct cpufreq_policy *policy);
>  void cpufreq_update_policy(unsigned int cpu);
>  void cpufreq_update_limits(unsigned int cpu);
> +void cpufreq_update_highest_perf(unsigned int cpu);
>  bool have_governor_per_policy(void);
>  bool cpufreq_supports_freq_invariance(void);
>  struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
> @@ -377,6 +378,9 @@ struct cpufreq_driver {
>  	/* Called to update policy limits on firmware notifications. */
>  	void		(*update_limits)(unsigned int cpu);
>  
> +	/* Called to update highest performance on firmware notifications. */
> +	void		(*update_highest_perf)(unsigned int cpu);
> +

Can we use the existing `update_limits` callback?

Thanks,
Wyes
>  	/* optional */
>  	int		(*bios_limit)(int cpu, unsigned int *limit);
>  
> -- 
> 2.34.1
> 

RE: [PATCH V3 4/7] cpufreq: Add a notification message that the highest perf has changed

[Meng, Li (Jassmine)]

[AMD Official Use Only - General]

Hello Wyes:

> -----Original Message-----
> From: Karny, Wyes <Wyes.Karny@amd.com>
> Sent: Thursday, August 24, 2023 7:19 PM
> To: Meng, Li (Jassmine) <Li.Meng@amd.com>
> Cc: Karny, Wyes <Wyes.Karny@amd.com>; 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 V3 4/7] cpufreq: Add a notification message that the
> highest perf has changed
>
> On 24 Aug 10:12, 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         |  4 ++++
> >  3 files changed, 23 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;
> > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > index 50bbc969ffe5..842357abfae6 100644
> > --- a/drivers/cpufreq/cpufreq.c
> > +++ b/drivers/cpufreq/cpufreq.c
> > @@ -2675,6 +2675,19 @@ void cpufreq_update_limits(unsigned int cpu)  }
> > EXPORT_SYMBOL_GPL(cpufreq_update_limits);
> >
> > +/**
> > + * cpufreq_update_highest_perf - Update highest performance for a
> given CPU.
> > + * @cpu: CPU to update the highest performance for.
> > + *
> > + * Invoke the driver's ->update_highest_perf callback if present  */
> > +void cpufreq_update_highest_perf(unsigned int cpu) {
> > +   if (cpufreq_driver->update_highest_perf)
> > +           cpufreq_driver->update_highest_perf(cpu);
> > +}
> > +EXPORT_SYMBOL_GPL(cpufreq_update_highest_perf);
> > +
> >
> /**********************************************************
> ***********
> >   *               BOOST                                                  *
> >
> >
> **********************************************************
> ***********/
> > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index
> > 9bf94ae08158..58106b3d9183 100644
> > --- a/include/linux/cpufreq.h
> > +++ b/include/linux/cpufreq.h
> > @@ -232,6 +232,7 @@ int cpufreq_get_policy(struct cpufreq_policy
> > *policy, unsigned int cpu);  void refresh_frequency_limits(struct
> > cpufreq_policy *policy);  void cpufreq_update_policy(unsigned int
> > cpu);  void cpufreq_update_limits(unsigned int cpu);
> > +void cpufreq_update_highest_perf(unsigned int cpu);
> >  bool have_governor_per_policy(void);
> >  bool cpufreq_supports_freq_invariance(void);
> >  struct kobject *get_governor_parent_kobj(struct cpufreq_policy
> > *policy); @@ -377,6 +378,9 @@ struct cpufreq_driver {
> >     /* Called to update policy limits on firmware notifications. */
> >     void            (*update_limits)(unsigned int cpu);
> >
> > +   /* Called to update highest performance on firmware notifications.
> */
> > +   void            (*update_highest_perf)(unsigned int cpu);
> > +
>
> Can we use the existing `update_limits` callback?
>
> Thanks,
> Wyes
[Meng, Li (Jassmine)]
I think there is a difference between the two functions.
When ACPI received ACPI_PROCESSOR_NOTIFY_PERFORMANCE event, it will call 'update_limits' to update policy data.
However 'update_highest_perf' handles the message ACPI_PROCESSOR_NOTIFY_HIGHEST_PERF_CHANGED.

> >     /* optional */
> >     int             (*bios_limit)(int cpu, unsigned int *limit);
> >
> > --
> > 2.34.1
> >

[PATCH V3 5/7] cpufreq: amd-pstate: Update AMD Pstate Preferred Core ranking dynamically

[Meng Li]

Preferred core rankings can be changed dynamically by the
platform based on the workload and platform conditions and
accounting for thermals and aging.
When this occurs, cpu priority need to be set.

Signed-off-by: Meng Li <li.meng@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 32 ++++++++++++++++++++++++++++++++
 include/linux/amd-pstate.h   |  1 +
 2 files changed, 33 insertions(+)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index d02305675f66..8a8e4ecb1b5c 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -315,6 +315,7 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
 	WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));
 	WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
 	WRITE_ONCE(cpudata->lowest_perf, AMD_CPPC_LOWEST_PERF(cap1));
+	WRITE_ONCE(cpudata->prefcore_highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
 
 	return 0;
 }
@@ -336,6 +337,7 @@ static int cppc_init_perf(struct amd_cpudata *cpudata)
 	WRITE_ONCE(cpudata->lowest_nonlinear_perf,
 		   cppc_perf.lowest_nonlinear_perf);
 	WRITE_ONCE(cpudata->lowest_perf, cppc_perf.lowest_perf);
+	WRITE_ONCE(cpudata->prefcore_highest_perf, cppc_perf.highest_perf);
 
 	if (cppc_state == AMD_PSTATE_ACTIVE)
 		return 0;
@@ -744,6 +746,34 @@ static void amd_pstate_init_prefcore(void)
 	schedule_work(&sched_prefcore_work);
 }
 
+static void amd_pstate_update_highest_perf(unsigned int cpu)
+{
+	struct cpufreq_policy *policy;
+	struct amd_cpudata *cpudata;
+	u32 prev_high = 0, cur_high = 0;
+	u64 highest_perf;
+	int ret;
+
+	if (!prefcore)
+		return;
+
+	ret = amd_pstate_get_highest_perf(cpu, &highest_perf);
+	if (ret)
+		return;
+
+	policy = cpufreq_cpu_get(cpu);
+	cpudata = policy->driver_data;
+	cur_high = highest_perf;
+	prev_high = READ_ONCE(cpudata->prefcore_highest_perf);
+
+	if (prev_high != cur_high) {
+		WRITE_ONCE(cpudata->prefcore_highest_perf, cur_high);
+		sched_set_itmt_core_prio(cur_high, cpu);
+	}
+
+	cpufreq_cpu_put(policy);
+}
+
 static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 {
 	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
@@ -1468,6 +1498,7 @@ static struct cpufreq_driver amd_pstate_driver = {
 	.suspend	= amd_pstate_cpu_suspend,
 	.resume		= amd_pstate_cpu_resume,
 	.set_boost	= amd_pstate_set_boost,
+	.update_highest_perf	= amd_pstate_update_highest_perf,
 	.name		= "amd-pstate",
 	.attr		= amd_pstate_attr,
 };
@@ -1482,6 +1513,7 @@ static struct cpufreq_driver amd_pstate_epp_driver = {
 	.online		= amd_pstate_epp_cpu_online,
 	.suspend	= amd_pstate_epp_suspend,
 	.resume		= amd_pstate_epp_resume,
+	.update_highest_perf	= amd_pstate_update_highest_perf,
 	.name		= "amd-pstate-epp",
 	.attr		= amd_pstate_epp_attr,
 };
diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
index 446394f84606..fa86bc953d3e 100644
--- a/include/linux/amd-pstate.h
+++ b/include/linux/amd-pstate.h
@@ -70,6 +70,7 @@ struct amd_cpudata {
 	u32	nominal_perf;
 	u32	lowest_nonlinear_perf;
 	u32	lowest_perf;
+	u32     prefcore_highest_perf;
 
 	u32	max_freq;
 	u32	min_freq;
-- 
2.34.1

Re: [PATCH V3 5/7] cpufreq: amd-pstate: Update AMD Pstate Preferred Core ranking dynamically

[Wyes Karny]

On 24 Aug 10:12, Meng Li wrote:
> Preferred core rankings can be changed dynamically by the
> platform based on the workload and platform conditions and
> accounting for thermals and aging.
> When this occurs, cpu priority need to be set.
> 
> Signed-off-by: Meng Li <li.meng@amd.com>
> ---
>  drivers/cpufreq/amd-pstate.c | 32 ++++++++++++++++++++++++++++++++
>  include/linux/amd-pstate.h   |  1 +
>  2 files changed, 33 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index d02305675f66..8a8e4ecb1b5c 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -315,6 +315,7 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
>  	WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));
>  	WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
>  	WRITE_ONCE(cpudata->lowest_perf, AMD_CPPC_LOWEST_PERF(cap1));
> +	WRITE_ONCE(cpudata->prefcore_highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
>  
>  	return 0;
>  }
> @@ -336,6 +337,7 @@ static int cppc_init_perf(struct amd_cpudata *cpudata)
>  	WRITE_ONCE(cpudata->lowest_nonlinear_perf,
>  		   cppc_perf.lowest_nonlinear_perf);
>  	WRITE_ONCE(cpudata->lowest_perf, cppc_perf.lowest_perf);
> +	WRITE_ONCE(cpudata->prefcore_highest_perf, cppc_perf.highest_perf);
>  
>  	if (cppc_state == AMD_PSTATE_ACTIVE)
>  		return 0;
> @@ -744,6 +746,34 @@ static void amd_pstate_init_prefcore(void)
>  	schedule_work(&sched_prefcore_work);
>  }
>  
> +static void amd_pstate_update_highest_perf(unsigned int cpu)
> +{
> +	struct cpufreq_policy *policy;
> +	struct amd_cpudata *cpudata;
> +	u32 prev_high = 0, cur_high = 0;
> +	u64 highest_perf;
> +	int ret;
> +
> +	if (!prefcore)
> +		return;
> +
> +	ret = amd_pstate_get_highest_perf(cpu, &highest_perf);
> +	if (ret)
> +		return;
> +
> +	policy = cpufreq_cpu_get(cpu);
> +	cpudata = policy->driver_data;
> +	cur_high = highest_perf;
> +	prev_high = READ_ONCE(cpudata->prefcore_highest_perf);
> +
> +	if (prev_high != cur_high) {
> +		WRITE_ONCE(cpudata->prefcore_highest_perf, cur_high);
> +		sched_set_itmt_core_prio(cur_high, cpu);
> +	}
> +
> +	cpufreq_cpu_put(policy);
> +}
> +
>  static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  {
>  	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
> @@ -1468,6 +1498,7 @@ static struct cpufreq_driver amd_pstate_driver = {
>  	.suspend	= amd_pstate_cpu_suspend,
>  	.resume		= amd_pstate_cpu_resume,
>  	.set_boost	= amd_pstate_set_boost,
> +	.update_highest_perf	= amd_pstate_update_highest_perf,
>  	.name		= "amd-pstate",
>  	.attr		= amd_pstate_attr,
>  };
> @@ -1482,6 +1513,7 @@ static struct cpufreq_driver amd_pstate_epp_driver = {
>  	.online		= amd_pstate_epp_cpu_online,
>  	.suspend	= amd_pstate_epp_suspend,
>  	.resume		= amd_pstate_epp_resume,
> +	.update_highest_perf	= amd_pstate_update_highest_perf,
>  	.name		= "amd-pstate-epp",
>  	.attr		= amd_pstate_epp_attr,

If we intend to use the existing `update_limits` callback then this
patch needed to update. Otherwise looks good to me.

Reviewed-by: Wyes Karny <wyes.karny@amd.com>

>  };
> diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> index 446394f84606..fa86bc953d3e 100644
> --- a/include/linux/amd-pstate.h
> +++ b/include/linux/amd-pstate.h
> @@ -70,6 +70,7 @@ struct amd_cpudata {
>  	u32	nominal_perf;
>  	u32	lowest_nonlinear_perf;
>  	u32	lowest_perf;
> +	u32     prefcore_highest_perf;
>  
>  	u32	max_freq;
>  	u32	min_freq;
> -- 
> 2.34.1
> 

[PATCH V3 6/7] Documentation: amd-pstate: introduce AMD Pstate Preferred Core

[Meng Li]

Introduce AMD Pstate Preferred Core.

check preferred core state:
$ cat /sys/devices/system/cpu/amd-pstate/prefcore

Signed-off-by: Meng Li <li.meng@amd.com>
---
 Documentation/admin-guide/pm/amd-pstate.rst | 53 +++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 1cf40f69278c..2369b58a3521 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -353,6 +353,47 @@ is activated.  In this mode, driver requests minimum and maximum performance
 level and the platform autonomously selects a performance level in this range
 and appropriate to the current workload.
 
+AMD Pstate Preferred Core
+=================================
+
+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.
+
+``AMD Pstate Preferred Core`` enable the scheduler to favor scheduling on cores
+can be get a higher frequency with lower voltage under preferred core.
+And it has the ability to dynamically change the preferred core based on the
+workload and platform conditions and accounting for thermals and aging.
+
+The priority metric will be initialized by the AMD Pstate driver. The AMD Pstate
+driver will also determine whether or not ``AMD Pstate Preferred Core`` is
+supported by the platform.
+
+AMD Pstate driver will provide an initial core ordering when the system boots.
+The platform uses the CPPC interfaces 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 and set the cpu's priority.
+
+AMD Preferred Core Switch
+=================================
+Kernel Parameters
+-----------------
+
+``AMD Pstate Preferred Core`` has two states: enable and disable.
+Enable/disable states can be chosen by different kernel parameters.
+Default enable ``AMD Pstate Preferred Core``.
+
+``amd_prefcore=disable``
+
+``AMD Pstate Preferred Core`` will be enabled if the underlying platform
+supports it. It can be disabled by kernerl parameter: ``amd_prefcore=disable``.
+
 User Space Interface in ``sysfs`` - General
 ===========================================
 
@@ -385,6 +426,18 @@ control its functionality at the system level.  They are located in the
         to the operation mode represented by that string - or to be
         unregistered in the "disable" case.
 
+``prefcore``
+	Preferred Core state of the driver: "enabled" or "disabled".
+
+	"enabled"
+		Enable the AMD Preferred Core.
+
+	"disabled"
+		Disable the AMD Preferred Core
+
+
+        This attribute is read-only to check the state of Preferred Core.
+
 ``cpupower`` tool support for ``amd-pstate``
 ===============================================
 
-- 
2.34.1

Re: [PATCH V3 6/7] Documentation: amd-pstate: introduce AMD Pstate Preferred Core

[Wyes Karny]

On 24 Aug 10:12, Meng Li wrote:
> Introduce AMD Pstate Preferred Core.
> 
> check preferred core state:
> $ cat /sys/devices/system/cpu/amd-pstate/prefcore
> 
> Signed-off-by: Meng Li <li.meng@amd.com>
> ---
>  Documentation/admin-guide/pm/amd-pstate.rst | 53 +++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
> index 1cf40f69278c..2369b58a3521 100644
> --- a/Documentation/admin-guide/pm/amd-pstate.rst
> +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> @@ -353,6 +353,47 @@ is activated.  In this mode, driver requests minimum and maximum performance
>  level and the platform autonomously selects a performance level in this range
>  and appropriate to the current workload.
>  
> +AMD Pstate Preferred Core
> +=================================
> +
> +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.
> +

---------------------------->8----------------------------------
> +``AMD Pstate Preferred Core`` enable the scheduler to favor scheduling on cores
> +can be get a higher frequency with lower voltage under preferred core.
> +And it has the ability to dynamically change the preferred core based on the
> +workload and platform conditions and accounting for thermals and aging.

Can we reword this like below:

``AMD Pstate Preferred Core`` enables the scheduler to prefer scheduling
on cores that can achieve a higher frequency with lower voltage.  The
preferred core rankings can dynamically change based on the workload,
platform conditions, thermals and ageing.

> +
> +The priority metric will be initialized by the AMD Pstate driver. The AMD Pstate
> +driver will also determine whether or not ``AMD Pstate Preferred Core`` is
> +supported by the platform.
> +
> +AMD Pstate driver will provide an initial core ordering when the system boots.
> +The platform uses the CPPC interfaces 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 and set the cpu's priority.
> +
> +AMD Preferred Core Switch
> +=================================
> +Kernel Parameters
> +-----------------
> +

----------------------------->8------------------------------
> +``AMD Pstate Preferred Core`` has two states: enable and disable.
> +Enable/disable states can be chosen by different kernel parameters.
> +Default enable ``AMD Pstate Preferred Core``.
> +
> +``amd_prefcore=disable``
> +
> +``AMD Pstate Preferred Core`` will be enabled if the underlying platform
> +supports it. It can be disabled by kernerl parameter: ``amd_prefcore=disable``.

Can we re-word this like below:

``amd_prefcore=disable``

For systems that support ``AMD Pstate Preferred Core``, the core
rankings will always be advertised by the platform. But OS can choose to
ignore that via the kernel parameter ``amd_prefcore=disable``.


Thanks,
Wyes
> +
>  User Space Interface in ``sysfs`` - General
>  ===========================================
>  
> @@ -385,6 +426,18 @@ control its functionality at the system level.  They are located in the
>          to the operation mode represented by that string - or to be
>          unregistered in the "disable" case.
>  
> +``prefcore``
> +	Preferred Core state of the driver: "enabled" or "disabled".
> +
> +	"enabled"
> +		Enable the AMD Preferred Core.
> +
> +	"disabled"
> +		Disable the AMD Preferred Core
> +
> +
> +        This attribute is read-only to check the state of Preferred Core.
> +
>  ``cpupower`` tool support for ``amd-pstate``
>  ===============================================
>  
> -- 
> 2.34.1
> 

[PATCH V3 7/7] Documentation: introduce AMD Pstate Preferrd Core mode kernel command line options

[Meng Li]

AMD Pstate driver support enable/disable Preferred core.
Default enabled on platforms supporting AMD Preferred Core.
Disable AMD Pstate Preferred Core with
"amd_prefcore=disable" added to the kernel command line.

Signed-off-by: Meng Li <li.meng@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 23ebe34ff901..4f78067bb8af 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -363,6 +363,11 @@
 			  selects a performance level in this range and appropriate
 			  to the current workload.
 
+	amd_prefcore=
+			[X86]
+			disable
+			  Disable AMD Pstate Preferred Core.
+
 	amijoy.map=	[HW,JOY] Amiga joystick support
 			Map of devices attached to JOY0DAT and JOY1DAT
 			Format: <a>,<b>
-- 
2.34.1

Re: [PATCH V3 7/7] Documentation: introduce AMD Pstate Preferrd Core mode kernel command line options

[Wyes Karny]

On 24 Aug 10:12, Meng Li wrote:
> AMD Pstate driver support enable/disable Preferred core.
> Default enabled on platforms supporting AMD Preferred Core.
> Disable AMD Pstate Preferred Core with
> "amd_prefcore=disable" added to the kernel command line.
> 
> Signed-off-by: Meng Li <li.meng@amd.com>
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>

> ---
>  Documentation/admin-guide/kernel-parameters.txt | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 23ebe34ff901..4f78067bb8af 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -363,6 +363,11 @@
>  			  selects a performance level in this range and appropriate
>  			  to the current workload.
>  
> +	amd_prefcore=
> +			[X86]
> +			disable
> +			  Disable AMD Pstate Preferred Core.
> +
>  	amijoy.map=	[HW,JOY] Amiga joystick support
>  			Map of devices attached to JOY0DAT and JOY1DAT
>  			Format: <a>,<b>
> -- 
> 2.34.1
> 

Re: [PATCH V3 0/7] AMD Pstate Preferred Core

[Mario Limonciello]

On 8/23/2023 21:12, 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 Preferrred 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 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   |  53 ++++++
>   arch/x86/Kconfig                              |   5 +-
>   drivers/acpi/cppc_acpi.c                      |  13 ++
>   drivers/acpi/processor_driver.c               |   6 +
>   drivers/cpufreq/amd-pstate.c                  | 152 ++++++++++++++++--
>   drivers/cpufreq/cpufreq.c                     |  13 ++
>   include/acpi/cppc_acpi.h                      |   5 +
>   include/linux/amd-pstate.h                    |   1 +
>   include/linux/cpufreq.h                       |   4 +
>   10 files changed, 239 insertions(+), 18 deletions(-)
> 
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>