Messages in this thread | | | Date | Thu, 14 Mar 2024 15:11:36 +0530 | From | "Gautham R. Shenoy" <> | Subject | Re: [PATCH v4 2/7] cpufreq: amd-pstate: implement cpb_boost sysfs entry for boost control |
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Hello Perry,
On Wed, Mar 13, 2024 at 06:04:39PM +0800, Perry Yuan wrote: > From: Perry Yuan <Perry.Yuan@amd.com> > > 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
Could you please elaborate on the need for this new interface when /sys/devices/system/cpu/cpufreq/boost exists and is being used in the other cpufreq driver namely the acpi-cpufreq driver ?
The semantics of this new interface seems to be identical to the existing boost interface.
I am ok with the rest of the patch, but please explain the need for a new interface.
-- Thanks and Regards gautham.
> > 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@amd.com> > --- > drivers/cpufreq/amd-pstate.c | 97 ++++++++++++++++++++++++++++++++++++ > 1 file changed, 97 insertions(+) > > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index ef6381b48e76..d54399ebb758 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -1208,6 +1208,101 @@ static ssize_t prefcore_show(struct device *dev, > return sysfs_emit(buf, "%s\n", str_enabled_disabled(amd_pstate_prefcore)); > } > > +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); > + > + 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) { > + 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 * 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); > + } > + > + 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", 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; > + > + mutex_lock(&amd_pstate_driver_lock); > + 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 -EINVAL; > + > + amd_pstate_global_params.cpb_boost = !!new_state; > + > + for_each_online_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, amd_pstate_global_params.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); > > @@ -1218,6 +1313,7 @@ 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, > @@ -1242,6 +1338,7 @@ 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 > }; > > -- > 2.34.1 >
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