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Subject[PATCH v10 6/7] cpufreq: amd-pstate: introduce per CPU frequency boost control
Date
Add a new sysfs attribute file to support per CPU frequency boost
control, allowing individual CPUs to enable or disable CPB separately.

The new sysfs attribute file is located at below path,
`/sys/devices/system/cpu/cpuX/cpufreq/boost`,
where `X` represents the CPU number.

To disable CPB for a specific CPU, you can use the following command:
$ sudo bash -c "echo 0 > /sys/devices/system/cpu/cpuX/cpufreq/boost"

After disabling CPB, the CPU frequency will no longer boost beyond
the base frequency for that particular CPU.

for example:
----------------------------------------------------------------------
CPU NODE SOCKET CORE L1d:L1i:L2:L3 ONLINE MAXMHZ MINMHZ MHZ
0 0 0 0 0:0:0:0 yes 4208.0000 400.0000 1666.7740
1 0 0 0 0:0:0:0 yes 4208.0000 400.0000 400.0000

----------------------------------------------------------------------
$ sudo bash -c "echo 0 > /sys/devices/system/cpu/cpu0/cpufreq/boost"

CPU NODE SOCKET CORE L1d:L1i:L2:L3 ONLINE MAXMHZ MINMHZ MHZ
0 0 0 0 0:0:0:0 yes 3501.0000 400.0000 4154.3140
1 0 0 0 0:0:0:0 yes 4208.0000 400.0000 400.0000

Please be aware that modifying the global variable
`amd_pstate_global_params.cpb_boost` will overwrite the individual CPU settings.

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
drivers/cpufreq/amd-pstate.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 11bce2c1db32..cb0055e7c842 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1371,6 +1371,30 @@ static int amd_pstate_cpu_boost(int cpu, bool state)
return ret < 0 ? ret : 0;
}

+static ssize_t show_boost(struct cpufreq_policy *policy, char *buf)
+{
+ struct amd_cpudata *cpudata = policy->driver_data;
+ bool boost_val;
+
+ boost_val = READ_ONCE(cpudata->boost_state);
+
+ return sysfs_emit(buf, "%u\n", boost_val);
+}
+
+static ssize_t store_boost(
+ struct cpufreq_policy *policy, const char *buf, size_t count)
+{
+ bool boost_val;
+ int ret;
+
+ if (sscanf(buf, "%d", &boost_val) != 1)
+ return -EINVAL;
+
+ ret = amd_pstate_cpu_boost(policy->cpu, boost_val);
+
+ return ret < 0 ? ret : count;
+}
+
static ssize_t cpb_boost_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -1416,6 +1440,7 @@ cpufreq_freq_attr_ro(amd_pstate_prefcore_ranking);
cpufreq_freq_attr_ro(amd_pstate_hw_prefcore);
cpufreq_freq_attr_rw(energy_performance_preference);
cpufreq_freq_attr_ro(energy_performance_available_preferences);
+cpufreq_freq_attr_rw(boost);
static DEVICE_ATTR_RW(status);
static DEVICE_ATTR_RO(prefcore);
static DEVICE_ATTR_RW(cpb_boost);
@@ -1426,6 +1451,7 @@ static struct freq_attr *amd_pstate_attr[] = {
&amd_pstate_highest_perf,
&amd_pstate_prefcore_ranking,
&amd_pstate_hw_prefcore,
+ &boost,
NULL,
};

@@ -1437,6 +1463,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
&amd_pstate_hw_prefcore,
&energy_performance_preference,
&energy_performance_available_preferences,
+ &boost,
NULL,
};

--
2.34.1

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