Re: [PATCH v11 5/9] cpufreq: amd-pstate: implement cpb_boost sysfs entry for boost control
From: Mario Limonciello
Date: Thu Jun 13 2024 - 13:55:27 EST
On 6/13/2024 02:25, Perry Yuan wrote:
From: Perry Yuan <Perry.Yuan@xxxxxxx>
With this new sysfs entry `cpb_boost`created, user can change CPU boost
state dynamically under `active`, `guided` 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 <Perry.Yuan@xxxxxxx>
---
drivers/cpufreq/amd-pstate-ut.c | 2 +-
drivers/cpufreq/amd-pstate.c | 117 +++++++++++++++++++++++++++++++-
drivers/cpufreq/amd-pstate.h | 1 +
3 files changed, 118 insertions(+), 2 deletions(-)
diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c
index fc275d41d51e..b528f198f4c3 100644
--- a/drivers/cpufreq/amd-pstate-ut.c
+++ b/drivers/cpufreq/amd-pstate-ut.c
@@ -227,7 +227,7 @@ static void amd_pstate_ut_check_freq(u32 index)
goto skip_test;
}
- if (cpudata->boost_supported) {
+ if (amd_pstate_global_params.cpb_boost) {
if ((policy->max == cpudata->max_freq) ||
(policy->max == cpudata->nominal_freq))
amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 9f42524074a9..fe7c9d3562c5 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -104,6 +104,7 @@ static bool amd_pstate_prefcore = true;
static struct quirk_entry *quirks;
struct amd_pstate_global_params amd_pstate_global_params;
EXPORT_SYMBOL_GPL(amd_pstate_global_params);
+static int amd_pstate_cpu_boost(int cpu, bool state);
/*
* AMD Energy Preference Performance (EPP)
@@ -738,6 +739,7 @@ static int amd_pstate_boost_set(struct amd_cpudata *cpudata)
if (amd_pstate_global_params.cpb_supported) {
current_pstate_driver->boost_enabled = true;
WRITE_ONCE(cpudata->boost_supported, true);
+ WRITE_ONCE(cpudata->boost_state, true);
}
amd_pstate_global_params.cpb_boost = amd_pstate_global_params.cpb_supported;
@@ -745,6 +747,7 @@ static int amd_pstate_boost_set(struct amd_cpudata *cpudata)
exit_err:
WRITE_ONCE(cpudata->boost_supported, false);
+ WRITE_ONCE(cpudata->boost_state, false);
current_pstate_driver->boost_enabled = false;
amd_pstate_global_params.cpb_boost = false;
return ret;
@@ -1348,6 +1351,116 @@ static ssize_t prefcore_show(struct device *dev,
return sysfs_emit(buf, "%s\n", str_enabled_disabled(amd_pstate_prefcore));
}
+static int amd_pstate_cpu_boost_update(struct cpufreq_policy *policy, bool on)
+{
+ struct amd_cpudata *cpudata = policy->driver_data;
+ struct cppc_perf_ctrls perf_ctrls;
+ u32 highest_perf, nominal_perf, nominal_freq, max_freq;
+ int ret;
+
+ if (!policy) {
+ pr_err("policy is null\n");
+ return -ENODATA;
+ }
This is dead code that can't possibly be hit, because there would be a
NULL pointer dereference above for this line:
struct amd_cpudata *cpudata = policy->driver_data;
Furthermore, the caller for this function, amd_pstate_cpu_boost() has
the same check already.
So drop the check here.
+
+ highest_perf = READ_ONCE(cpudata->highest_perf);
+ nominal_perf = READ_ONCE(cpudata->nominal_perf);
+ nominal_freq = READ_ONCE(cpudata->nominal_freq);
+ max_freq = READ_ONCE(cpudata->max_freq);
+
+ if (boot_cpu_has(X86_FEATURE_CPPC)) {
+ u64 value = READ_ONCE(cpudata->cppc_req_cached);
+
+ value &= ~GENMASK_ULL(7, 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) {
+ cpufreq_cpu_release(policy);
+ pr_debug("failed to set energy perf value (%d)\n", ret);
+ return ret;
+ }
+ }
+
+ if (on)
+ policy->cpuinfo.max_freq = max_freq;
+ else
+ policy->cpuinfo.max_freq = nominal_freq * 1000;
+
+ policy->max = policy->cpuinfo.max_freq;
+
+ if (cppc_state == AMD_PSTATE_PASSIVE) {
+ ret = freq_qos_update_request(&cpudata->req[1], policy->cpuinfo.max_freq);
+ if (ret < 0)
+ pr_debug("Failed to update freq constraint: CPU%d\n", cpudata->cpu);
+ }
+
+ return ret < 0 ? ret : 0;
+}
+
+static int amd_pstate_cpu_boost(int cpu, bool state)
+{
+ int ret;
+ struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+ struct amd_cpudata *cpudata = policy->driver_data;
+
+ if (!policy) {
+ pr_err("policy is NULL\n");
+ ret = -ENODATA;
+ goto err_exit;
+ }
+
+ ret = amd_pstate_cpu_boost_update(policy, state);
+ refresh_frequency_limits(policy);
+ WRITE_ONCE(cpudata->boost_state, state);
+ policy->boost_enabled = state;
+
+err_exit:
+ cpufreq_cpu_put(policy);
+ return ret < 0 ? ret : 0;
+}
+
+static ssize_t cpb_boost_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "%u\n", amd_pstate_global_params.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;
+
+ if (!amd_pstate_global_params.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 ret;
+
+ mutex_lock(&amd_pstate_driver_lock);
+ for_each_present_cpu(cpu) {
+ ret = amd_pstate_cpu_boost(cpu, new_state);
+ if (ret < 0) {
+ pr_warn("failed to update cpu boost for CPU%d (%zd)\n", cpu, ret);
+ goto err_exit;
+ }
+ }
+ amd_pstate_global_params.cpb_boost = !!new_state;
+
+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);
@@ -1358,6 +1471,7 @@ 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 DEVICE_ATTR_RW(cpb_boost);
static struct freq_attr *amd_pstate_attr[] = {
&amd_pstate_max_freq,
@@ -1382,6 +1496,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
static struct attribute *pstate_global_attributes[] = {
&dev_attr_status.attr,
&dev_attr_prefcore.attr,
+ &dev_attr_cpb_boost.attr,
NULL
};
@@ -1420,7 +1535,7 @@ static int amd_pstate_init_boost(struct cpufreq_policy *policy)
if (ret)
return ret;
- policy->boost_enabled = READ_ONCE(cpudata->boost_supported);
+ policy->boost_enabled = READ_ONCE(cpudata->boost_state);
return 0;
}
diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h
index 0b75a6267fca..9eba854ab7d3 100644
--- a/drivers/cpufreq/amd-pstate.h
+++ b/drivers/cpufreq/amd-pstate.h
@@ -99,6 +99,7 @@ struct amd_cpudata {
u32 policy;
u64 cppc_cap1_cached;
bool suspended;
+ bool boost_state;
};
/**