| Message ID | 20250321022858.1538173-5-superm1@kernel.org (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | Mario Limonciello |
| Headers | show |
| Series | amd-pstate Dynamic EPP and raw EPP | expand |
On 3/21/2025 7:58 AM, Mario Limonciello wrote: > From: Mario Limonciello <mario.limonciello@amd.com> > > The energy performance preference field of the CPPC request MSR > supports values from 0 to 255, but the strings only offer 4 values. > > The other values are useful for tuning the performance of some > workloads. > > Add support for writing the raw energy performance preference value > to the sysfs file. If the last value written was an integer then > an integer will be returned. If the last value written was a string > then a string will be returned. LGTM Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com> > > Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> > --- > Documentation/admin-guide/pm/amd-pstate.rst | 16 +++++++++++----- > drivers/cpufreq/amd-pstate.c | 11 +++++++++-- > drivers/cpufreq/amd-pstate.h | 1 + > 3 files changed, 21 insertions(+), 7 deletions(-) > > diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst > index 36950fb6568c0..0e4d2e0aaeff7 100644 > --- a/Documentation/admin-guide/pm/amd-pstate.rst > +++ b/Documentation/admin-guide/pm/amd-pstate.rst > @@ -280,16 +280,22 @@ A list of all the supported EPP preferences that could be used for > These profiles represent different hints that are provided > to the low-level firmware about the user's desired energy vs efficiency > tradeoff. ``default`` represents the epp value is set by platform > -firmware. This attribute is read-only. > +firmware. ``custom`` designates that integer values 0-255 may be written > +as well. This attribute is read-only. > > ``energy_performance_preference`` > > The current energy performance preference can be read from this attribute. > and user can change current preference according to energy or performance needs > -Please get all support profiles list from > -``energy_performance_available_preferences`` attribute, all the profiles are > -integer values defined between 0 to 255 when EPP feature is enabled by platform > -firmware, but if the dynamic EPP feature is enabled, driver will block writes. > +Coarse named profiles are available in the attribute > +``energy_performance_available_preferences``. > +Users can also write individual integer values between 0 to 255. > +When EPP feature is enabled by platform firmware but if the dynamic EPP feature is > +enabled, driver will ignore the written value. Lower epp values shift the bias > +towards improved performance while a higher epp value shifts the bias towards > +power-savings. The exact impact can change from one platform to the other. > +If a valid integer was last written, then a number will be returned on future reads. > +If a valid string was last written then a string will be returned on future reads. > This attribute is read-write. > > ``boost`` > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index 2a62b12148544..b0de50f390e07 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -1318,6 +1318,7 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy, > struct amd_cpudata *cpudata = policy->driver_data; > char str_preference[21]; > ssize_t ret; > + bool raw_epp = FALSE; > u8 epp; > > if (cpudata->dynamic_epp) { > @@ -1334,6 +1335,7 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy, > * matches an index in the energy_perf_strings array > */ > ret = kstrtou8(str_preference, 0, &epp); > + raw_epp = !ret; > if (ret) { > ret = match_string(energy_perf_strings, -1, str_preference); > if (ret < 0 || ret == EPP_INDEX_CUSTOM) > @@ -1353,7 +1355,9 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy, > if (ret) > return ret; > > - return ret ? ret : count; > + cpudata->raw_epp = raw_epp; > + > + return count; > } > EXPORT_SYMBOL_GPL(store_energy_performance_preference); > > @@ -1364,6 +1368,9 @@ ssize_t show_energy_performance_preference(struct cpufreq_policy *policy, char * > > epp = FIELD_GET(AMD_CPPC_EPP_PERF_MASK, cpudata->cppc_req_cached); > > + if (cpudata->raw_epp) > + return sysfs_emit(buf, "%u\n", epp); > + > switch (epp) { > case AMD_CPPC_EPP_PERFORMANCE: > preference = EPP_INDEX_PERFORMANCE; > @@ -1378,7 +1385,7 @@ ssize_t show_energy_performance_preference(struct cpufreq_policy *policy, char * > preference = EPP_INDEX_POWERSAVE; > break; > default: > - return sysfs_emit(buf, "%u\n", epp); > + return -EINVAL; > } > > return sysfs_emit(buf, "%s\n", energy_perf_strings[preference]); > diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h > index b4c5374762110..b6be2b8fbffbf 100644 > --- a/drivers/cpufreq/amd-pstate.h > +++ b/drivers/cpufreq/amd-pstate.h > @@ -108,6 +108,7 @@ struct amd_cpudata { > u8 epp_default_ac; > u8 epp_default_dc; > bool dynamic_epp; > + bool raw_epp; > struct notifier_block power_nb; > > /* platform profile */
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst index 36950fb6568c0..0e4d2e0aaeff7 100644 --- a/Documentation/admin-guide/pm/amd-pstate.rst +++ b/Documentation/admin-guide/pm/amd-pstate.rst @@ -280,16 +280,22 @@ A list of all the supported EPP preferences that could be used for These profiles represent different hints that are provided to the low-level firmware about the user's desired energy vs efficiency tradeoff. ``default`` represents the epp value is set by platform -firmware. This attribute is read-only. +firmware. ``custom`` designates that integer values 0-255 may be written +as well. This attribute is read-only. ``energy_performance_preference`` The current energy performance preference can be read from this attribute. and user can change current preference according to energy or performance needs -Please get all support profiles list from -``energy_performance_available_preferences`` attribute, all the profiles are -integer values defined between 0 to 255 when EPP feature is enabled by platform -firmware, but if the dynamic EPP feature is enabled, driver will block writes. +Coarse named profiles are available in the attribute +``energy_performance_available_preferences``. +Users can also write individual integer values between 0 to 255. +When EPP feature is enabled by platform firmware but if the dynamic EPP feature is +enabled, driver will ignore the written value. Lower epp values shift the bias +towards improved performance while a higher epp value shifts the bias towards +power-savings. The exact impact can change from one platform to the other. +If a valid integer was last written, then a number will be returned on future reads. +If a valid string was last written then a string will be returned on future reads. This attribute is read-write. ``boost`` diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 2a62b12148544..b0de50f390e07 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -1318,6 +1318,7 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy, struct amd_cpudata *cpudata = policy->driver_data; char str_preference[21]; ssize_t ret; + bool raw_epp = FALSE; u8 epp; if (cpudata->dynamic_epp) { @@ -1334,6 +1335,7 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy, * matches an index in the energy_perf_strings array */ ret = kstrtou8(str_preference, 0, &epp); + raw_epp = !ret; if (ret) { ret = match_string(energy_perf_strings, -1, str_preference); if (ret < 0 || ret == EPP_INDEX_CUSTOM) @@ -1353,7 +1355,9 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy, if (ret) return ret; - return ret ? ret : count; + cpudata->raw_epp = raw_epp; + + return count; } EXPORT_SYMBOL_GPL(store_energy_performance_preference); @@ -1364,6 +1368,9 @@ ssize_t show_energy_performance_preference(struct cpufreq_policy *policy, char * epp = FIELD_GET(AMD_CPPC_EPP_PERF_MASK, cpudata->cppc_req_cached); + if (cpudata->raw_epp) + return sysfs_emit(buf, "%u\n", epp); + switch (epp) { case AMD_CPPC_EPP_PERFORMANCE: preference = EPP_INDEX_PERFORMANCE; @@ -1378,7 +1385,7 @@ ssize_t show_energy_performance_preference(struct cpufreq_policy *policy, char * preference = EPP_INDEX_POWERSAVE; break; default: - return sysfs_emit(buf, "%u\n", epp); + return -EINVAL; } return sysfs_emit(buf, "%s\n", energy_perf_strings[preference]); diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h index b4c5374762110..b6be2b8fbffbf 100644 --- a/drivers/cpufreq/amd-pstate.h +++ b/drivers/cpufreq/amd-pstate.h @@ -108,6 +108,7 @@ struct amd_cpudata { u8 epp_default_ac; u8 epp_default_dc; bool dynamic_epp; + bool raw_epp; struct notifier_block power_nb; /* platform profile */