This change uses acpi cppc_lib interface to get CPPC performance limits.
Once CPPC limits of all online cores are read, first check if there is
difference in max performance. If there is a difference, then the
scheduler interface is called to update per cpu priority and enable
ITMT feature.
Here sched_set_itmt_core_prio() is called to set priorities and
sched_set_itmt_support() is called to enable ITMT feature.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
---
drivers/cpufreq/Kconfig.x86 | 1 +
drivers/cpufreq/intel_pstate.c | 103 ++++++++++++++++++++++++++++++++++++++++-
2 files changed, 103 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86
index adbd1de..3328c6b 100644
--- a/drivers/cpufreq/Kconfig.x86
+++ b/drivers/cpufreq/Kconfig.x86
@@ -6,6 +6,7 @@ config X86_INTEL_PSTATE
bool "Intel P state control"
depends on X86
select ACPI_PROCESSOR if ACPI
+ select ACPI_CPPC_LIB if X86_64 && ACPI
help
This driver provides a P state for Intel core processors.
The driver implements an internal governor and will become
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index c877e70..d226a64 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -44,6 +44,7 @@
#ifdef CONFIG_ACPI
#include <acpi/processor.h>
+#include <acpi/cppc_acpi.h>
#endif
#define FRAC_BITS 8
@@ -195,6 +196,7 @@ struct _pid {
* @sample: Storage for storing last Sample data
* @acpi_perf_data: Stores ACPI perf information read from _PSS
* @valid_pss_table: Set to true for valid ACPI _PSS entries found
+ * @cppc_perf: Stores CPPC performance information
*
* This structure stores per CPU instance data for all CPUs.
*/
@@ -218,6 +220,7 @@ struct cpudata {
#ifdef CONFIG_ACPI
struct acpi_processor_performance acpi_perf_data;
bool valid_pss_table;
+ struct cppc_perf_caps *cppc_perf;
#endif
unsigned int iowait_boost;
};
@@ -377,14 +380,105 @@ static bool intel_pstate_get_ppc_enable_status(void)
return acpi_ppc;
}
+/* Mask of CPUs for which CPCC data has been read */
+static cpumask_t cppc_read_cpu_mask;
+
+/*
+ * Can't call sched_set_itmt_support() in hotcpu notifier callback path
+ * as this function uses hotplug locks in its path. So call from
+ * a work function.
+ */
+static void intel_pstste_sched_itmt_work_fn(struct work_struct *work)
+{
+ sched_set_itmt_support(true);
+}
+
+static DECLARE_WORK(sched_itmt_work, intel_pstste_sched_itmt_work_fn);
+
+static void intel_pstate_check_and_enable_itmt(int cpu)
+{
+ /*
+ * For checking whether there is any difference in the maximum
+ * performance for each CPU, need to wait till we have CPPC
+ * data from all CPUs called from the cpufreq core. If there is a
+ * difference in the maximum performance, then we have ITMT support.
+ * If ITMT is supported, update the scheduler core priority for each
+ * CPU and call to enable the ITMT feature.
+ */
+ if (cpumask_subset(topology_core_cpumask(cpu), &cppc_read_cpu_mask)) {
+ int cpu_index;
+ int max_prio;
+ struct cpudata *cpu;
+ bool itmt_support = false;
+
+ cpu = all_cpu_data[cpumask_first(&cppc_read_cpu_mask)];
+ max_prio = cpu->cppc_perf->highest_perf;
+ for_each_cpu(cpu_index, &cppc_read_cpu_mask) {
+ cpu = all_cpu_data[cpu_index];
+ if (max_prio != cpu->cppc_perf->highest_perf) {
+ itmt_support = true;
+ break;
+ }
+ }
+
+ if (!itmt_support)
+ return;
+
+ for_each_cpu(cpu_index, &cppc_read_cpu_mask) {
+ cpu = all_cpu_data[cpu_index];
+ sched_set_itmt_core_prio(cpu->cppc_perf->highest_perf,
+ cpu_index);
+ }
+ /*
+ * Since this function is in the hotcpu notifier callback
+ * path, submit a task to workqueue to call
+ * sched_set_itmt_support().
+ */
+ schedule_work(&sched_itmt_work);
+ }
+}
+
+/*
+ * Process ACPI CPPC information. Currently it is only used to for enabling
+ * ITMT feature. This driver still uses MSRs to manage HWP, not CPPC.
+ */
+static void intel_pstate_process_acpi_cppc(struct cpufreq_policy *policy)
+{
+ struct cpudata *cpu;
+ int ret;
+
+ cpu = all_cpu_data[policy->cpu];
+ cpu->cppc_perf = kzalloc(sizeof(struct cppc_perf_caps), GFP_KERNEL);
+ if (!cpu->cppc_perf)
+ return;
+
+ ret = cppc_get_perf_caps(policy->cpu, cpu->cppc_perf);
+ if (ret) {
+ kfree(cpu->cppc_perf);
+ cpu->cppc_perf = NULL;
+ return;
+ }
+
+ pr_debug("cpu:%d H:0x%x N:0x%x L:0x%x\n", policy->cpu,
+ cpu->cppc_perf->highest_perf, cpu->cppc_perf->nominal_perf,
+ cpu->cppc_perf->lowest_perf);
+
+ /* Mark that the CPPC data for the policy->cpu is read */
+ cpumask_set_cpu(policy->cpu, &cppc_read_cpu_mask);
+
+ intel_pstate_check_and_enable_itmt(policy->cpu);
+}
+
static void intel_pstate_init_acpi_perf_limits(struct cpufreq_policy *policy)
{
struct cpudata *cpu;
int ret;
int i;
- if (hwp_active)
+ if (hwp_active) {
+ intel_pstate_process_acpi_cppc(policy);
return;
+ }
if (!intel_pstate_get_ppc_enable_status())
return;
@@ -450,6 +544,13 @@ static void intel_pstate_exit_perf_limits(struct cpufreq_policy *policy)
struct cpudata *cpu;
cpu = all_cpu_data[policy->cpu];
+
+ if (cpu->cppc_perf) {
+ cpumask_clear_cpu(policy->cpu, &cppc_read_cpu_mask);
+ kfree(cpu->cppc_perf);
+ cpu->cppc_perf = NULL;
+ }
+
if (!cpu->valid_pss_table)
return;
--
2.7.4
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