amd-pstate driver utilizes the functions and data structures provided by the ITMT architecture to enable the scheduler to favor scheduling on cores which can be get a higher frequency with lower voltage. We call it amd-pstate preferrred core.
Here sched_set_itmt_core_prio() is called to set priorities and sched_set_itmt_support() is called to enable ITMT feature. amd-pstate driver uses the highest performance value to indicate the priority of CPU. The higher value has a higher priority.
The initial core rankings are set up by amd-pstate when the system boots.
Add a variable hw_prefcore in cpudata structure. It will check if the processor and power firmware support preferred core feature.
Add one new early parameter `disable` to allow user to disable the preferred core.
Only when hardware supports preferred core and user set `enabled` in early parameter, amd pstate driver supports preferred core featue.
Tested-by: Oleksandr Natalenko oleksandr@natalenko.name Reviewed-by: Huang Rui ray.huang@amd.com Reviewed-by: Wyes Karny wyes.karny@amd.com Reviewed-by: Mario Limonciello mario.limonciello@amd.com Co-developed-by: Perry Yuan Perry.Yuan@amd.com Signed-off-by: Perry Yuan Perry.Yuan@amd.com Signed-off-by: Meng Li li.meng@amd.com --- drivers/cpufreq/amd-pstate.c | 155 +++++++++++++++++++++++++++++++---- include/linux/amd-pstate.h | 4 + 2 files changed, 143 insertions(+), 16 deletions(-)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 9a1e194d5cf8..6aae383990f1 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -37,6 +37,7 @@ #include <linux/uaccess.h> #include <linux/static_call.h> #include <linux/amd-pstate.h> +#include <linux/topology.h>
#include <acpi/processor.h> #include <acpi/cppc_acpi.h> @@ -49,6 +50,8 @@
#define AMD_PSTATE_TRANSITION_LATENCY 20000 #define AMD_PSTATE_TRANSITION_DELAY 1000 +#define AMD_PSTATE_PREFCORE_THRESHOLD 166 +#define AMD_PSTATE_MAX_CPPC_PERF 255
/* * TODO: We need more time to fine tune processors with shared memory solution @@ -64,6 +67,7 @@ static struct cpufreq_driver amd_pstate_driver; static struct cpufreq_driver amd_pstate_epp_driver; static int cppc_state = AMD_PSTATE_UNDEFINED; static bool cppc_enabled; +static bool amd_pstate_prefcore = true;
/* * AMD Energy Preference Performance (EPP) @@ -290,23 +294,21 @@ static inline int amd_pstate_enable(bool enable) static int pstate_init_perf(struct amd_cpudata *cpudata) { u64 cap1; - u32 highest_perf;
int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1, &cap1); if (ret) return ret;
- /* - * TODO: Introduce AMD specific power feature. - * - * CPPC entry doesn't indicate the highest performance in some ASICs. + /* For platforms that do not support the preferred core feature, the + * highest_pef may be configured with 166 or 255, to avoid max frequency + * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1) value as + * the default max perf. */ - highest_perf = amd_get_highest_perf(); - if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1)) - highest_perf = AMD_CPPC_HIGHEST_PERF(cap1); - - WRITE_ONCE(cpudata->highest_perf, highest_perf); + if (cpudata->hw_prefcore) + WRITE_ONCE(cpudata->highest_perf, AMD_PSTATE_PREFCORE_THRESHOLD); + else + WRITE_ONCE(cpudata->highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1)); WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1)); @@ -318,17 +320,15 @@ static int pstate_init_perf(struct amd_cpudata *cpudata) static int cppc_init_perf(struct amd_cpudata *cpudata) { struct cppc_perf_caps cppc_perf; - u32 highest_perf;
int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); if (ret) return ret;
- highest_perf = amd_get_highest_perf(); - if (highest_perf > cppc_perf.highest_perf) - highest_perf = cppc_perf.highest_perf; - - WRITE_ONCE(cpudata->highest_perf, highest_perf); + if (cpudata->hw_prefcore) + WRITE_ONCE(cpudata->highest_perf, AMD_PSTATE_PREFCORE_THRESHOLD); + else + WRITE_ONCE(cpudata->highest_perf, cppc_perf.highest_perf);
WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf); WRITE_ONCE(cpudata->lowest_nonlinear_perf, @@ -676,6 +676,93 @@ static void amd_perf_ctl_reset(unsigned int cpu) wrmsrl_on_cpu(cpu, MSR_AMD_PERF_CTL, 0); }
+/* + * Set amd-pstate preferred core enable can't be done directly from cpufreq callbacks + * due to locking, so queue the work for later. + */ +static void amd_pstste_sched_prefcore_workfn(struct work_struct *work) +{ + sched_set_itmt_support(); +} +static DECLARE_WORK(sched_prefcore_work, amd_pstste_sched_prefcore_workfn); + +/* + * Get the highest performance register value. + * @cpu: CPU from which to get highest performance. + * @highest_perf: Return address. + * + * Return: 0 for success, -EIO otherwise. + */ +static int amd_pstate_get_highest_perf(int cpu, u32 *highest_perf) +{ + int ret; + + if (boot_cpu_has(X86_FEATURE_CPPC)) { + u64 cap1; + + ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &cap1); + if (ret) + return ret; + WRITE_ONCE(*highest_perf, AMD_CPPC_HIGHEST_PERF(cap1)); + } else { + u64 cppc_highest_perf; + + ret = cppc_get_highest_perf(cpu, &cppc_highest_perf); + WRITE_ONCE(*highest_perf, cppc_highest_perf); + } + + return (ret); +} + +static void amd_pstate_init_prefcore(struct amd_cpudata *cpudata) +{ + int ret, prio; + u32 highest_perf; + static u32 max_highest_perf = 0, min_highest_perf = U32_MAX; + + ret = amd_pstate_get_highest_perf(cpudata->cpu, &highest_perf); + if (ret) + return; + + cpudata->hw_prefcore = true; + /* check if CPPC preferred core feature is enabled*/ + if (highest_perf == AMD_PSTATE_MAX_CPPC_PERF) { + pr_debug("AMD CPPC preferred core is unsupported!\n"); + cpudata->hw_prefcore = false; + return; + } + + if (!amd_pstate_prefcore) + return; + + /* The maximum value of highest perf is 255 */ + prio = (int)(highest_perf & 0xff); + /* + * The priorities can be set regardless of whether or not + * sched_set_itmt_support(true) has been called and it is valid to + * update them at any time after it has been called. + */ + sched_set_itmt_core_prio(prio, cpudata->cpu); + + if (max_highest_perf <= min_highest_perf) { + if (highest_perf > max_highest_perf) + max_highest_perf = highest_perf; + + if (highest_perf < min_highest_perf) + min_highest_perf = highest_perf; + + if (max_highest_perf > min_highest_perf) { + /* + * This code can be run during CPU online under the + * CPU hotplug locks, so sched_set_itmt_support() + * cannot be called from here. Queue up a work item + * to invoke it. + */ + schedule_work(&sched_prefcore_work); + } + } +} + static int amd_pstate_cpu_init(struct cpufreq_policy *policy) { int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret; @@ -697,6 +784,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
cpudata->cpu = policy->cpu;
+ amd_pstate_init_prefcore(cpudata); + ret = amd_pstate_init_perf(cpudata); if (ret) goto free_cpudata1; @@ -845,6 +934,17 @@ static ssize_t show_amd_pstate_highest_perf(struct cpufreq_policy *policy, return sysfs_emit(buf, "%u\n", perf); }
+static ssize_t show_amd_pstate_hw_prefcore(struct cpufreq_policy *policy, + char *buf) +{ + bool hw_prefcore; + struct amd_cpudata *cpudata = policy->driver_data; + + hw_prefcore = READ_ONCE(cpudata->hw_prefcore); + + return sysfs_emit(buf, "%s\n", hw_prefcore ? "supported" : "unsupported"); +} + static ssize_t show_energy_performance_available_preferences( struct cpufreq_policy *policy, char *buf) { @@ -1037,18 +1137,27 @@ static ssize_t status_store(struct device *a, struct device_attribute *b, return ret < 0 ? ret : count; }
+static ssize_t prefcore_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%s\n", amd_pstate_prefcore ? "enabled" : "disabled"); +} + cpufreq_freq_attr_ro(amd_pstate_max_freq); cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
cpufreq_freq_attr_ro(amd_pstate_highest_perf); +cpufreq_freq_attr_ro(amd_pstate_hw_prefcore); 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 struct freq_attr *amd_pstate_attr[] = { &amd_pstate_max_freq, &amd_pstate_lowest_nonlinear_freq, &amd_pstate_highest_perf, + &amd_pstate_hw_prefcore, NULL, };
@@ -1056,6 +1165,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = { &amd_pstate_max_freq, &amd_pstate_lowest_nonlinear_freq, &amd_pstate_highest_perf, + &amd_pstate_hw_prefcore, &energy_performance_preference, &energy_performance_available_preferences, NULL, @@ -1063,6 +1173,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
static struct attribute *pstate_global_attributes[] = { &dev_attr_status.attr, + &dev_attr_prefcore.attr, NULL };
@@ -1114,6 +1225,8 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) cpudata->cpu = policy->cpu; cpudata->epp_policy = 0;
+ amd_pstate_init_prefcore(cpudata); + ret = amd_pstate_init_perf(cpudata); if (ret) goto free_cpudata1; @@ -1527,7 +1640,17 @@ static int __init amd_pstate_param(char *str)
return amd_pstate_set_driver(mode_idx); } + +static int __init amd_prefcore_param(char *str) +{ + if (!strcmp(str, "disable")) + amd_pstate_prefcore = false; + + return 0; +} + early_param("amd_pstate", amd_pstate_param); +early_param("amd_prefcore", amd_prefcore_param);
MODULE_AUTHOR("Huang Rui ray.huang@amd.com"); MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver"); diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h index 446394f84606..87e140e9e6db 100644 --- a/include/linux/amd-pstate.h +++ b/include/linux/amd-pstate.h @@ -52,6 +52,9 @@ struct amd_aperf_mperf { * @prev: Last Aperf/Mperf/tsc count value read from register * @freq: current cpu frequency value * @boost_supported: check whether the Processor or SBIOS supports boost mode + * @hw_prefcore: check whether HW supports preferred core featue. + * Only when hw_prefcore and early prefcore param are true, + * AMD P-State driver supports preferred core featue. * @epp_policy: Last saved policy used to set energy-performance preference * @epp_cached: Cached CPPC energy-performance preference value * @policy: Cpufreq policy value @@ -81,6 +84,7 @@ struct amd_cpudata {
u64 freq; bool boost_supported; + bool hw_prefcore;
/* EPP feature related attributes*/ s16 epp_policy;