AMD Pstate Driver Core Performance Boost

From: Perry Yuan <[email protected]>

The following patches will enable amd-pstate CPU boost control method

which will not need this common boost control callback anymore, so we remove the legacy set_boost interface from amd-pstate driver.

Signed-off-by Perry Yuan <[email protected]>

---
  drivers/cpufreq/amd-pstate.c | 26 --------------------------
  1 file changed, 26 deletions(-)

drivers/cpufreq/amd-pstate.c +0 -26

index 9a1e194d5cf8..8f308f56ade6 100644
@@ -632,31 +632,6 @@ 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)
-{
-	struct amd_cpudata *cpudata = policy->driver_data;
-	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)
-		return ret;
-
-	return 0;
-}
-
  static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
  {
  	u32 highest_perf, nominal_perf;

@@ -1391,7 +1366,6 @@ static struct cpufreq_driver amd_pstate_driver = {
  	.exit		= amd_pstate_cpu_exit,
  	.suspend	= amd_pstate_cpu_suspend,
  	.resume		= amd_pstate_cpu_resume,
-	.set_boost	= amd_pstate_set_boost,
  	.name		= "amd-pstate",
  	.attr		= amd_pstate_attr,
  };

-----Original Message-----
From: Limonciello, Mario <[email protected]>
Sent: Friday, January 26, 2024 11:45 PM
To: Yuan, Perry <[email protected]>; [email protected]; [email protected]; Huang, Ray <[email protected]>; Shenoy, Gautham Ranjal <[email protected]>; Petkov, Borislav <[email protected]>
Cc: Deucher, Alexander <[email protected]>; Huang, Shimmer <[email protected]>; Du, Xiaojian <[email protected]>; Meng, Li (Jassmine) <[email protected]>; [email protected]; linux- [email protected]
Subject: Re: [PATCH 1/7] cpufreq: amd-pstate: remove set_boost callback for passive mode

Quoted 2 lines · Perry Yuan

From: Perry Yuan <[email protected]>

Quoted 2 lines

The following patches will enable amd-pstate CPU boost control method

When it's committed it won't be a patch. How about instead "A specific amd- pstate CPU boost control method is to be introduced and the legacy callback doesn't make sense" or something along those lines.

Also; is the ordering correct? In terms of bisectability should this come after the new one is introduced perhaps?

Quoted 11 lines

which will not need this common boost control callback anymore, so we remove the legacy set_boost interface from amd-pstate driver.

Signed-off-by Perry Yuan <[email protected]>

---
  drivers/cpufreq/amd-pstate.c | 26 --------------------------
  1 file changed, 26 deletions(-)

(quoted diff) +0 -0

b/drivers/cpufreq/amd-pstate.c index 9a1e194d5cf8..8f308f56ade6

100644

drivers/cpufreq/amd-pstate.c static int amd_get_lowest_nonlinear_freq(struct

Quoted 3 lines

drivers/cpufreq/amd-pstate.c +0 -0

@@ -632,31 +632,6 @@ static int amd_get_lowest_nonlinear_freq(struct

amd_cpudata *cpudata)

drivers/cpufreq/amd-pstate.c static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)

Quoted 10 lines

drivers/cpufreq/amd-pstate.c +0 -6

    return lowest_nonlinear_freq * 1000;
  }
 
-static int amd_pstate_set_boost(struct cpufreq_policy *policy, int
 state) -{
-   struct amd_cpudata *cpudata = policy->driver_data;
-   int ret;
-
-   if (!cpudata->boost_supported) {
-           pr_err("Boost mode is not supported by this processor or

SBIOS\n");

drivers/cpufreq/amd-pstate.c static struct cpufreq_driver amd_pstate_driver =

Quoted 22 lines

drivers/cpufreq/amd-pstate.c +0 -18

-           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)
-           return ret;
-
-   return 0;
-}
-
  static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
  {
    u32 highest_perf, nominal_perf;

@@ -1391,7 +1366,6 @@ static struct cpufreq_driver amd_pstate_driver =

{

Quoted 7 lines

drivers/cpufreq/amd-pstate.c +0 -1

    .exit           = amd_pstate_cpu_exit,
    .suspend        = amd_pstate_cpu_suspend,
    .resume         = amd_pstate_cpu_resume,
-   .set_boost      = amd_pstate_set_boost,
    .name           = "amd-pstate",
    .attr           = amd_pstate_attr,
  };

From: Perry Yuan <[email protected]>

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.

Issue: https://bugzilla.kernel.org/show_bug.cgi?id=217931

Reported-by Artem S. Tashkinov" <[email protected]>

Signed-off-by Perry Yuan <[email protected]>

---
  drivers/cpufreq/amd-pstate.c | 46 ++++++++++++++++++++++++++++--------
  include/linux/amd-pstate.h   |  1 -
  2 files changed, 36 insertions(+), 11 deletions(-)

drivers/cpufreq/amd-pstate.c +21 -4

index 8f308f56ade6..0dc9124140d4 100644
@@ -65,6 +65,19 @@ static struct cpufreq_driver amd_pstate_epp_driver;
  static int cppc_state = AMD_PSTATE_UNDEFINED;
  static bool cppc_enabled;
 
+/**
+ * struct 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 global_params {
+	bool cpb_boost;
+	bool cpb_supported;
+};
+
+static struct global_params global;
+
  /*
   * AMD Energy Preference Performance (EPP)
   * The EPP is used in the CCLK DPM controller to drive

@@ -632,18 +645,27 @@ static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
  	return lowest_nonlinear_freq * 1000;
  }
 
-static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
+static int amd_pstate_boost_init(struct amd_cpudata *cpudata)
  {
-	u32 highest_perf, nominal_perf;
+	u64 boost_state, boost_val;
+	int ret;
 
-	highest_perf = READ_ONCE(cpudata->highest_perf);
-	nominal_perf = READ_ONCE(cpudata->nominal_perf);
+	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;
+	}
 

drivers/cpufreq/amd-pstate.c +7 -4

-	cpudata->boost_supported = true;
-	current_pstate_driver->boost_enabled = true;
+	return ret;
  }
 
  static void amd_perf_ctl_reset(unsigned int cpu)

@@ -676,6 +698,9 @@ 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);

@@ -725,7 +750,6 @@ 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;
 

@@ -1093,6 +1117,9 @@ 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);

@@ -1143,7 +1170,6 @@ 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;
 

include/linux/amd-pstate.h +0 -1

index 446394f84606..66d939a344b1 100644
@@ -80,7 +80,6 @@ struct amd_cpudata {
  	struct amd_aperf_mperf prev;
 
  	u64	freq;
-	bool	boost_supported;
 
  	/* EPP feature related attributes*/
  	s16	epp_policy;

From: Perry Yuan <[email protected]>

drivers/cpufreq/amd-pstate.c +1 -1

@@ -632,18 +645,27 @@ static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
 	return lowest_nonlinear_freq * 1000;
 }
 
-static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
+static int amd_pstate_boost_init(struct amd_cpudata *cpudata)

drivers/cpufreq/amd-pstate.c +7 -2

+		global.cpb_supported = true;
+		global.cpb_boost = true;
+	} else {
+		global.cpb_supported = false;
+		global.cpb_boost = false;
+	}
 
-	cpudata->boost_supported = true;
-	current_pstate_driver->boost_enabled = true;
+	return ret;
 }

static void amd_perf_ctl_reset(unsigned int cpu)

drivers/cpufreq/amd-pstate.c +6 -2

@@ -676,6 +698,9 @@ 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);

@@ -725,7 +750,6 @@ 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;
 

@@ -1093,6 +1117,9 @@ 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);

@@ -1143,7 +1170,6 @@ 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;
 

include/linux/amd-pstate.h +0 -1

index 446394f84606..66d939a344b1 100644
@@ -80,7 +80,6 @@ struct amd_cpudata {
 	struct amd_aperf_mperf prev;
 
 	u64	freq;
-	bool	boost_supported;
 
 	/* EPP feature related attributes*/
 	s16	epp_policy;

Signature · 1 line

2.34.1

From: Perry Yuan <[email protected]>

With this new sysfs entry cpb_boostcreated, user can change CPU boost state dynamically under active and passive modes.

And the highest perf and frequency will also be updated as the boost state changing.

0: check current boost state
cat /sys/devices/system/cpu/amd_pstate/cpb_boost

1: disable CPU boost
sudo bash -c "echo 0 > /sys/devices/system/cpu/amd_pstate/cpb_boost"

2: enable CPU boost
sudo bash -c "echo 1 > /sys/devices/system/cpu/amd_pstate/cpb_boost"

Link https://bugzilla.kernel.org/show_bug.cgi?id=217931

Link https://bugzilla.kernel.org/show_bug.cgi?id=217618

Signed-off-by Perry Yuan <[email protected]>

---
  drivers/cpufreq/amd-pstate.c | 97 ++++++++++++++++++++++++++++++++++++
  1 file changed, 97 insertions(+)

drivers/cpufreq/amd-pstate.c +7 -0

index 0dc9124140d4..b37bea7440b9 100644
@@ -1036,6 +1036,101 @@ static ssize_t status_store(struct device *a, struct device_attribute *b,
  	return ret < 0 ? ret : count;
  }
 
+static int amd_cpu_boost_update(struct amd_cpudata *cpudata, u32 on)
+{
+	struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpudata->cpu);
+	struct cppc_perf_ctrls perf_ctrls;
+	u32 highest_perf, nominal_perf;
+	int ret;
+

drivers/cpufreq/amd-pstate.c +80 -0

+		value |= on ? highest_perf : nominal_perf;
+		WRITE_ONCE(cpudata->cppc_req_cached, value);
+
+		wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
+
+	} else {
+		perf_ctrls.max_perf = on ? highest_perf : nominal_perf;
+		ret = cppc_set_epp_perf(cpudata->cpu, &perf_ctrls, 1);
+		if (ret) {
+			pr_debug("failed to set energy perf value (%d)\n", ret);
+			return ret;
+		}
+	}
+
+	if (on)
+		policy->cpuinfo.max_freq = cpudata->max_freq;
+	else
+		policy->cpuinfo.max_freq = cpudata->nominal_freq;
+
+	policy->max = policy->cpuinfo.max_freq;
+
+	if (cppc_state == AMD_PSTATE_PASSIVE) {
+		ret = freq_qos_update_request(&cpudata->req[1],
+				      policy->cpuinfo.max_freq);
+	}
+
+	cpufreq_cpu_release(policy);
+
+	return ret;
+}
+
+static ssize_t cpb_boost_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%u\n", global.cpb_boost);
+}
+
+static ssize_t cpb_boost_store(struct device *dev, struct device_attribute *b,
+			    const char *buf, size_t count)
+{
+	bool new_state;
+	ssize_t ret;
+	int cpu;
+
+	mutex_lock(&amd_pstate_driver_lock);
+	if (!global.cpb_supported) {
+		pr_err("Boost mode is not supported by this processor or SBIOS\n");
+		return -EINVAL;
+	}
+
+	ret = kstrtobool(buf, &new_state);
+	if (ret)
+		return -EINVAL;
+
+	global.cpb_boost = !!new_state;
+
+	for_each_possible_cpu(cpu) {
+
+		struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+		struct amd_cpudata *cpudata = policy->driver_data;
+
+		if (!cpudata) {
+			pr_err("cpudata is NULL\n");
+			ret = -ENODATA;
+			cpufreq_cpu_put(policy);
+			goto err_exit;
+		}
+
+		amd_cpu_boost_update(cpudata, global.cpb_boost);
+		refresh_frequency_limits(policy);
+		cpufreq_cpu_put(policy);
+	}
+
+err_exit:
+	mutex_unlock(&amd_pstate_driver_lock);
+	return ret < 0 ? ret : count;
+}
+
  cpufreq_freq_attr_ro(amd_pstate_max_freq);
  cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
 

@@ -1043,6 +1138,7 @@ 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_RW(cpb_boost);
 
  static struct freq_attr *amd_pstate_attr[] = {
  	&amd_pstate_max_freq,

@@ -1062,6 +1158,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
 
  static struct attribute *pstate_global_attributes[] = {
  	&dev_attr_status.attr,
+	&dev_attr_cpb_boost.attr,
  	NULL
  };
 

-----Original Message-----
From: Limonciello, Mario <[email protected]>
Sent: Friday, January 26, 2024 11:57 PM
To: Yuan, Perry <[email protected]>; [email protected]; [email protected]; Huang, Ray <[email protected]>; Shenoy, Gautham Ranjal <[email protected]>; Petkov, Borislav <[email protected]>
Cc: Deucher, Alexander <[email protected]>; Huang, Shimmer <[email protected]>; Du, Xiaojian <[email protected]>; Meng, Li (Jassmine) <[email protected]>; [email protected]; linux- [email protected]
Subject: Re: [PATCH 3/7] cpufreq: amd-pstate: implement cpb_boost sysfs entry for boost control

Quoted 4 lines · Perry Yuan

From: Perry Yuan <[email protected]>

With this new sysfs entry cpb_boostcreated, user can change CPU boost state dynamically under active and passive modes.

What about guided mode?

Quoted 12 lines

And the highest perf and frequency will also be updated as the boost state changing.

0: check current boost state
cat /sys/devices/system/cpu/amd_pstate/cpb_boost

1: disable CPU boost
sudo bash -c "echo 0 > /sys/devices/system/cpu/amd_pstate/cpb_boost"

2: enable CPU boost
sudo bash -c "echo 1 > /sys/devices/system/cpu/amd_pstate/cpb_boost"

Quoted 6 lines

Link https://bugzilla.kernel.org/show_bug.cgi?id=217931

Link https://bugzilla.kernel.org/show_bug.cgi?id=217618

Signed-off-by Perry Yuan <[email protected]>

---
  drivers/cpufreq/amd-pstate.c | 97

++++++++++++++++++++++++++++++++++++

Quoted 4 lines

  1 file changed, 97 insertions(+)

(quoted diff) +0 -0

b/drivers/cpufreq/amd-pstate.c index 0dc9124140d4..b37bea7440b9

100644

drivers/cpufreq/amd-pstate.c static ssize_t status_store(struct device *a,

Quoted 3 lines

drivers/cpufreq/amd-pstate.c +0 -0

@@ -1036,6 +1036,101 @@ static ssize_t status_store(struct device *a,

struct device_attribute *b,

Quoted 15 lines

drivers/cpufreq/amd-pstate.c +12 -0

    return ret < 0 ? ret : count;
  }
 
+static int amd_cpu_boost_update(struct amd_cpudata *cpudata, u32 on)
+{
+   struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpudata->cpu);
+   struct cppc_perf_ctrls perf_ctrls;
+   u32 highest_perf, nominal_perf;
+   int ret;
+
+   if (!policy)
+           return -ENODATA;
+
+   highest_perf = READ_ONCE(cpudata->highest_perf);
+   nominal_perf = READ_ONCE(cpudata->nominal_perf);

drivers/cpufreq/amd-pstate.c static ssize_t status_store(struct device *a, struct device_attribute *b, · line 1055

Quoted 5 lines

drivers/cpufreq/amd-pstate.c +5 -0

+
+   if (boot_cpu_has(X86_FEATURE_CPPC)) {
+           u64 value = READ_ONCE(cpudata->cppc_req_cached);
+
+           value &= ~GENMASK_ULL(7, 0);

I think it's better to use the macro AMD_CPPC_MAX_PERF in this case. The less magic masks in the code, the easier it is to follow.

drivers/cpufreq/amd-pstate.c static ssize_t status_store(struct device *a, struct device_attribute *b,

Quoted 5 lines

drivers/cpufreq/amd-pstate.c +4 -0

+           value |= on ? highest_perf : nominal_perf;
+           WRITE_ONCE(cpudata->cppc_req_cached, value);
+
+           wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,

value);

drivers/cpufreq/amd-pstate.c static ssize_t status_store(struct device *a, struct device_attribute *b,

Quoted 6 lines

drivers/cpufreq/amd-pstate.c +6 -0

+
+   } else {
+           perf_ctrls.max_perf = on ? highest_perf : nominal_perf;
+           ret = cppc_set_epp_perf(cpudata->cpu, &perf_ctrls, 1);
+           if (ret) {
+                   pr_debug("failed to set energy perf value (%d)\n",

ret);

Quoted 16 lines

drivers/cpufreq/amd-pstate.c +16 -0

+                   return ret;
+           }
+   }
+
+   if (on)
+           policy->cpuinfo.max_freq = cpudata->max_freq;
+   else
+           policy->cpuinfo.max_freq = cpudata->nominal_freq;
+
+   policy->max = policy->cpuinfo.max_freq;
+
+   if (cppc_state == AMD_PSTATE_PASSIVE) {
+           ret = freq_qos_update_request(&cpudata->req[1],
+                                 policy->cpuinfo.max_freq);
+   }
+

drivers/cpufreq/amd-pstate.c static ssize_t status_store(struct device *a, struct device_attribute *b,

Quoted 10 lines

drivers/cpufreq/amd-pstate.c +10 -0

+   cpufreq_cpu_release(policy);
+
+   return ret;
+}
+
+static ssize_t cpb_boost_show(struct device *dev,
+                      struct device_attribute *attr, char *buf) {
+   return sysfs_emit(buf, "%u\n", global.cpb_boost); }
+
+static ssize_t cpb_boost_store(struct device *dev, struct device_attribute

*b,

drivers/cpufreq/amd-pstate.c static ssize_t status_store(struct device *a, struct device_attribute *b,

Quoted 8 lines

drivers/cpufreq/amd-pstate.c +8 -0

+                       const char *buf, size_t count) {
+   bool new_state;
+   ssize_t ret;
+   int cpu;
+
+   mutex_lock(&amd_pstate_driver_lock);
+   if (!global.cpb_supported) {
+           pr_err("Boost mode is not supported by this processor or

SBIOS\n");

drivers/cpufreq/amd-pstate.c

Quoted 35 lines

drivers/cpufreq/amd-pstate.c +31 -0

+           return -EINVAL;
+   }
+
+   ret = kstrtobool(buf, &new_state);
+   if (ret)
+           return -EINVAL;
+
+   global.cpb_boost = !!new_state;
+
+   for_each_possible_cpu(cpu) {
+
+           struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+           struct amd_cpudata *cpudata = policy->driver_data;
+
+           if (!cpudata) {
+                   pr_err("cpudata is NULL\n");
+                   ret = -ENODATA;
+                   cpufreq_cpu_put(policy);
+                   goto err_exit;
+           }
+
+           amd_cpu_boost_update(cpudata, global.cpb_boost);
+           refresh_frequency_limits(policy);
+           cpufreq_cpu_put(policy);
+   }
+
+err_exit:
+   mutex_unlock(&amd_pstate_driver_lock);
+   return ret < 0 ? ret : count;
+}
+
  cpufreq_freq_attr_ro(amd_pstate_max_freq);
  cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
 

@@ -1043,6 +1138,7 @@

cpufreq_freq_attr_ro(amd_pstate_highest_perf);

Quoted 16 lines

drivers/cpufreq/amd-pstate.c +2 -0

  cpufreq_freq_attr_rw(energy_performance_preference);
  cpufreq_freq_attr_ro(energy_performance_available_preferences);
  static DEVICE_ATTR_RW(status);
+static DEVICE_ATTR_RW(cpb_boost);
 
  static struct freq_attr *amd_pstate_attr[] = {
    &amd_pstate_max_freq,

@@ -1062,6 +1158,7 @@ static struct freq_attr *amd_pstate_epp_attr[] =
 {
 
  static struct attribute *pstate_global_attributes[] = {
    &dev_attr_status.attr,
+   &dev_attr_cpb_boost.attr,
    NULL
  };

From: Perry Yuan <[email protected]>

When CPU core Precision Boost state changed, the max frequency will also need to be updated according to the current boost state, if boost is disabled now, the max perf will be limited to nominal perf values. otherwise the max frequency will be showed wrongly.

Signed-off-by Perry Yuan <[email protected]>

---
  drivers/cpufreq/amd-pstate.c | 4 ++++
  1 file changed, 4 insertions(+)

drivers/cpufreq/amd-pstate.c +4 -0

index b37bea7440b9..3286d72f375e 100644
@@ -599,6 +599,10 @@ static int amd_get_max_freq(struct amd_cpudata *cpudata)
  	nominal_perf = READ_ONCE(cpudata->nominal_perf);
  	max_perf = READ_ONCE(cpudata->highest_perf);
 
+	/* when boost is off, the highest perf will be limited to nominal_perf */
+	if (!global.cpb_boost)
+		max_perf = nominal_perf;
+
  	boost_ratio = div_u64(max_perf << SCHED_CAPACITY_SHIFT,
  			      nominal_perf);
 

-----Original Message-----
From: Limonciello, Mario <[email protected]>
Sent: Friday, January 26, 2024 11:54 PM
To: Yuan, Perry <[email protected]>; [email protected]; [email protected]; Huang, Ray <[email protected]>; Shenoy, Gautham Ranjal <[email protected]>; Petkov, Borislav <[email protected]>
Cc: Deucher, Alexander <[email protected]>; Huang, Shimmer <[email protected]>; Du, Xiaojian <[email protected]>; Meng, Li (Jassmine) <[email protected]>; [email protected]; linux- [email protected]
Subject: Re: [PATCH 4/7] cpufreq: amd-pstate: fix max_perf calculation for amd_get_max_freq()

Quoted 2 lines · Perry Yuan

From: Perry Yuan <[email protected]>

Quoted 4 lines

When CPU core Precision Boost state changed, the max frequency will also need to be updated according to the current boost state, if boost is disabled now, the max perf will be limited to nominal perf values. otherwise the max frequency will be showed wrongly.

What about the previous cppc_req? Shouldn't it be explicitly updated as a result of this too?

Quoted 9 lines

Signed-off-by Perry Yuan <[email protected]>

---
  drivers/cpufreq/amd-pstate.c | 4 ++++
  1 file changed, 4 insertions(+)

(quoted diff) +0 -0

b/drivers/cpufreq/amd-pstate.c index b37bea7440b9..3286d72f375e

100644

drivers/cpufreq/amd-pstate.c static int amd_get_max_freq(struct amd_cpudata

Quoted 3 lines

drivers/cpufreq/amd-pstate.c +0 -0

@@ -599,6 +599,10 @@ static int amd_get_max_freq(struct amd_cpudata

*cpudata)

Quoted 10 lines

drivers/cpufreq/amd-pstate.c +4 -0

    nominal_perf = READ_ONCE(cpudata->nominal_perf);
    max_perf = READ_ONCE(cpudata->highest_perf);
 
+   /* when boost is off, the highest perf will be limited to nominal_perf */
+   if (!global.cpb_boost)
+           max_perf = nominal_perf;
+
    boost_ratio = div_u64(max_perf << SCHED_CAPACITY_SHIFT,
                          nominal_perf);
 

From: Perry Yuan <[email protected]>

Add suspend and resume support for passive mode driver which can save the previous CPU Pstate values and restore them while resuming, on some old platforms, the highest perf needs to be restored from driver side, otherwise the highest frequency could be changed during suspend.

Signed-off-by Perry Yuan <[email protected]>

---
  drivers/cpufreq/amd-pstate.c | 48 ++++++++++++++++++++++++++++++++----
  1 file changed, 43 insertions(+), 5 deletions(-)

drivers/cpufreq/amd-pstate.c +3 -3

index 5cbbc2999d9a..bba7640d46e0 100644
@@ -785,23 +785,61 @@ static int amd_pstate_cpu_exit(struct cpufreq_policy *policy)
 
  static int amd_pstate_cpu_resume(struct cpufreq_policy *policy)
  {
+	struct cppc_perf_ctrls perf_ctrls;
+	struct amd_cpudata *cpudata = policy->driver_data;
+	u64 value, max_perf;
  	int ret;
 
-	ret = amd_pstate_enable(true);
-	if (ret)
-		pr_err("failed to enable amd-pstate during resume, return %d\n", ret);

drivers/cpufreq/amd-pstate.c +15 -0

+
+		value = READ_ONCE(cpudata->cppc_req_cached);
+		max_perf = READ_ONCE(cpudata->highest_perf);
+
+		if (boot_cpu_has(X86_FEATURE_CPPC)) {
+			wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
+		} else {
+			perf_ctrls.max_perf = max_perf;
+			cppc_set_perf(cpudata->cpu, &perf_ctrls);
+		}
+
+		cpudata->suspended = false;
+		mutex_unlock(&amd_pstate_driver_lock);
+	}
+

drivers/cpufreq/amd-pstate.c +14 -1

+	if (cppc_state != AMD_PSTATE_PASSIVE)
+		return 0;
+
+	mutex_lock(&amd_pstate_driver_lock);
+
+	/* set this flag to avoid calling core offline function
+	 * when system is suspending, use this flag to skip offline function
+	 * called
+	 */
+	cpudata->suspended = true;
+
  	ret = amd_pstate_enable(false);
  	if (ret)
  		pr_err("failed to disable amd-pstate during suspend, return %d\n", ret);
 
+	mutex_unlock(&amd_pstate_driver_lock);
+
  	return ret;
  }

@@ -1460,7 +1498,7 @@ static int amd_pstate_epp_suspend(struct cpufreq_policy *policy)
  	if (cppc_state != AMD_PSTATE_ACTIVE)
  		return 0;
 
-	/* set this flag to avoid setting core offline*/
+	/* set this flag to avoid setting core offline */
  	cpudata->suspended = true;
 
  	/* disable CPPC in lowlevel firmware */

From: Perry Yuan <[email protected]>

Introduce AMD CPU frequency boosting control sysfs entry which userd for switching boost on and boost off.

If core performance boost is disabled while a core is in a boosted P-state, the core automatically transitions to the highest performance non-boosted P-state The highest perf and frequency will be limited by the setting value.

Signed-off-by Perry Yuan <[email protected]>

---
  Documentation/admin-guide/pm/amd-pstate.rst | 11 +++++++++++
  1 file changed, 11 insertions(+)

Documentation/admin-guide/pm/amd-pstate.rst +0 -0

index 1cf40f69278c..d72dc407c4db 100644

Documentation/admin-guide/pm/amd-pstate.rst +4 -0

+
+        "0" Disable Core performance Boosting
+        "1" Enable  Core performance Boosting
+
  ``cpupower`` tool support for ``amd-pstate``
  ===============================================
 

-----Original Message-----
From: Limonciello, Mario <[email protected]>
Sent: Friday, January 26, 2024 11:47 PM
To: Yuan, Perry <[email protected]>; [email protected]; [email protected]; Huang, Ray <[email protected]>; Shenoy, Gautham Ranjal <[email protected]>; Petkov, Borislav <[email protected]>
Cc: Deucher, Alexander <[email protected]>; Huang, Shimmer <[email protected]>; Du, Xiaojian <[email protected]>; Meng, Li (Jassmine) <[email protected]>; [email protected]; linux- [email protected]
Subject: Re: [PATCH 7/7] Documentation: cpufreq: amd-pstate: introduce the new cpu boost control method

Quoted 4 lines · Perry Yuan

From: Perry Yuan <[email protected]>

Introduce AMD CPU frequency boosting control sysfs entry which userd for switching boost on and boost off.

Typo in this sentence.

Quoted 5 lines

If core performance boost is disabled while a core is in a boosted P-state, the core automatically transitions to the highest performance non-boosted P-state The highest perf and frequency will be limited by the

setting value.

Documentation/admin-guide/pm/amd-pstate.rst control its functionality at the system level. They

Quoted 12 lines

Signed-off-by Perry Yuan <[email protected]>

---
  Documentation/admin-guide/pm/amd-pstate.rst | 11 +++++++++++
  1 file changed, 11 insertions(+)

Documentation/admin-guide/pm/amd-pstate.rst +0 -0

index 1cf40f69278c..d72dc407c4db 100644
@@ -385,6 +385,17 @@ control its functionality at the system level.  They

are located in the

Documentation/admin-guide/pm/amd-pstate.rst control its functionality at the system level. They are located in the

Quoted 5 lines

Documentation/admin-guide/pm/amd-pstate.rst +2 -0

          to the operation mode represented by that string - or to be
          unregistered in the "disable" case.
 
+``cpb_boost``
+        Specifies whether core performance boost is requested to be enabled

or disabled

Documentation/admin-guide/pm/amd-pstate.rst control its functionality at the system level. They · line 390

Quoted 1 line

Documentation/admin-guide/pm/amd-pstate.rst +1 -0

+        If core performance boost is disabled while a core is in a boosted P-

state, the

Documentation/admin-guide/pm/amd-pstate.rst control its functionality at the system level. They · line 391

Quoted 1 line

Documentation/admin-guide/pm/amd-pstate.rst +1 -0

+        core automatically transitions to the highest performance non-boosted

P-state.

Documentation/admin-guide/pm/amd-pstate.rst control its functionality at the system level. They · line 392

Quoted 1 line

Documentation/admin-guide/pm/amd-pstate.rst +1 -0

+        AMD Core Performance Boost(CPB) is controlled by this new attribute

file which

Documentation/admin-guide/pm/amd-pstate.rst control its functionality at the system level. They · line 393

Quoted 1 line

Documentation/admin-guide/pm/amd-pstate.rst +1 -0

+        allow user to change all cores frequency boosting state. It supports

both

Documentation/admin-guide/pm/amd-pstate.rst control its functionality at the system level. They · line 394

Quoted 1 line

Documentation/admin-guide/pm/amd-pstate.rst +1 -0

+        ``active mode`` and ``passive mode`` control with below value write to

it.

Does it also support guided mode?

Quoted 8 lines

Documentation/admin-guide/pm/amd-pstate.rst +4 -0

+
+        "0" Disable Core performance Boosting
+        "1" Enable  Core performance Boosting
+
  ``cpupower`` tool support for ``amd-pstate``
  ===============================================