[PATCH v2 0/2] cpufreq: intel_pstate: Base frequency attribute

[PATCH v2 0/2] cpufreq: intel_pstate: Base frequency attribute

[Srinivas Pandruvada]

This series presents base frequency to cpufreq sysfs when intel_pstate
is in use in HWP mode.

Changes:
v2
- Removed guaranteed attribute addition to acpi_cppc sysfs
- Using the cppc_acpi interface to get base frequency and present

Srinivas Pandruvada (2):
  ACPI / CPPC: Add support for guaranteed performance
  cpufreq: intel_pstate: Add base_frequency attribute

 drivers/acpi/cppc_acpi.c       |  8 +++++--
 drivers/cpufreq/intel_pstate.c | 38 ++++++++++++++++++++++++++++++++++
 include/acpi/cppc_acpi.h       |  1 +
 3 files changed, 45 insertions(+), 2 deletions(-)

-- 
2.17.1

[PATCH v2 1/2] ACPI / CPPC: Add support for guaranteed performance

[Srinivas Pandruvada]

The Continuous Performance Control Package can have guaranteed performance
field. Add support to read guaranteed performance.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/acpi/cppc_acpi.c | 8 ++++++--
 include/acpi/cppc_acpi.h | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index d9ce4b162e2c..217a782c3e55 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1061,9 +1061,9 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 {
 	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
 	struct cpc_register_resource *highest_reg, *lowest_reg,
-		*lowest_non_linear_reg, *nominal_reg,
+		*lowest_non_linear_reg, *nominal_reg, *guaranteed_reg,
 		*low_freq_reg = NULL, *nom_freq_reg = NULL;
-	u64 high, low, nom, min_nonlinear, low_f = 0, nom_f = 0;
+	u64 high, low, guaranteed, nom, min_nonlinear, low_f = 0, nom_f = 0;
 	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
 	struct cppc_pcc_data *pcc_ss_data = NULL;
 	int ret = 0, regs_in_pcc = 0;
@@ -1079,6 +1079,7 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 	nominal_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
 	low_freq_reg = &cpc_desc->cpc_regs[LOWEST_FREQ];
 	nom_freq_reg = &cpc_desc->cpc_regs[NOMINAL_FREQ];
+	guaranteed_reg = &cpc_desc->cpc_regs[GUARANTEED_PERF];
 
 	/* Are any of the regs PCC ?*/
 	if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
@@ -1107,6 +1108,9 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 	cpc_read(cpunum, nominal_reg, &nom);
 	perf_caps->nominal_perf = nom;
 
+	cpc_read(cpunum, guaranteed_reg, &guaranteed);
+	perf_caps->guaranteed_perf = guaranteed;
+
 	cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear);
 	perf_caps->lowest_nonlinear_perf = min_nonlinear;
 
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 8e0b8250a139..cf59e6210d27 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -104,6 +104,7 @@ enum cppc_regs {
  * today.
  */
 struct cppc_perf_caps {
+	u32 guaranteed_perf;
 	u32 highest_perf;
 	u32 nominal_perf;
 	u32 lowest_perf;
-- 
2.17.1

[PATCH v2 2/2] cpufreq: intel_pstate: Add base_frequency attribute

[Srinivas Pandruvada]

Present base_frequency to user space via cpufreq sysfs when HWP is in
use.

This HWP base frequency is read from HWP Capabilities MSR, if platform
doesn't have ACPI _CPC object. On most of the HWP platforms the _CPC
object will point to the HWP Capabilities MSR using address space id as
"Functional Fixed Hardware". But the address space id can be simply
ACPI_TYPE_INTEGER, where the platform firmware can modify this value
based on the system constraints.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/cpufreq/intel_pstate.c | 38 ++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index b6a1aadaff9f..2a99e2fd9412 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -373,10 +373,28 @@ static void intel_pstate_set_itmt_prio(int cpu)
 		}
 	}
 }
+
+static int intel_pstate_get_cppc_guranteed(int cpu)
+{
+	struct cppc_perf_caps cppc_perf;
+	int ret;
+
+	ret = cppc_get_perf_caps(cpu, &cppc_perf);
+	if (ret)
+		return ret;
+
+	return cppc_perf.guaranteed_perf;
+}
+
 #else
 static void intel_pstate_set_itmt_prio(int cpu)
 {
 }
+
+static int intel_pstate_get_cppc_guranteed(int cpu)
+{
+	return -ENOTSUPP;
+}
 #endif
 
 static void intel_pstate_init_acpi_perf_limits(struct cpufreq_policy *policy)
@@ -699,9 +717,29 @@ static ssize_t show_energy_performance_preference(
 
 cpufreq_freq_attr_rw(energy_performance_preference);
 
+static ssize_t show_base_frequency(struct cpufreq_policy *policy, char *buf)
+{
+	struct cpudata *cpu;
+	u64 cap;
+	int ratio;
+
+	ratio = intel_pstate_get_cppc_guranteed(policy->cpu);
+	if (ratio <= 0) {
+		rdmsrl_on_cpu(policy->cpu, MSR_HWP_CAPABILITIES, &cap);
+		ratio = HWP_GUARANTEED_PERF(cap);
+	}
+
+	cpu = all_cpu_data[policy->cpu];
+
+	return sprintf(buf, "%d\n", ratio * cpu->pstate.scaling);
+}
+
+cpufreq_freq_attr_ro(base_frequency);
+
 static struct freq_attr *hwp_cpufreq_attrs[] = {
 	&energy_performance_preference,
 	&energy_performance_available_preferences,
+	&base_frequency,
 	NULL,
 };
 
-- 
2.17.1

Re: [PATCH v2 0/2] cpufreq: intel_pstate: Base frequency attribute

[Rafael J. Wysocki]

On Tue, Oct 9, 2018 at 11:46 PM Srinivas Pandruvada
<srinivas.pandruvada@linux.intel.com> wrote:
>
> This series presents base frequency to cpufreq sysfs when intel_pstate
> is in use in HWP mode.
>
> Changes:
> v2
> - Removed guaranteed attribute addition to acpi_cppc sysfs
> - Using the cppc_acpi interface to get base frequency and present

The code changes are fine by me, but what about documenting the new sysfs attr?

Thanks,
Rafael