--- /dev/null
+/*
+ * perf_event_intel_rapl.c: support Intel RAPL energy consumption counters
+ * Copyright (C) 2013 Google, Inc., Stephane Eranian
+ *
+ * Intel RAPL interface is specified in the IA-32 Manual Vol3b
+ * section 14.7.1 (September 2013)
+ *
+ * RAPL provides more controls than just reporting energy consumption
+ * however here we only expose the 3 energy consumption free running
+ * counters (pp0, pkg, dram).
+ *
+ * Each of those counters increments in a power unit defined by the
+ * RAPL_POWER_UNIT MSR. On SandyBridge, this unit is 1/(2^16) Joules
+ * but it can vary.
+ *
+ * Counter to rapl events mappings:
+ *
+ * pp0 counter: consumption of all physical cores (power plane 0)
+ * event: rapl_energy_cores
+ * perf code: 0x1
+ *
+ * pkg counter: consumption of the whole processor package
+ * event: rapl_energy_pkg
+ * perf code: 0x2
+ *
+ * dram counter: consumption of the dram domain (servers only)
+ * event: rapl_energy_dram
+ * perf code: 0x3
+ *
+ * We manage those counters as free running (read-only). They may be
+ * use simultaneously by other tools, such as turbostat.
+ *
+ * The events only support system-wide mode counting. There is no
+ * sampling support because it does not make sense and is not
+ * supported by the RAPL hardware.
+ *
+ * Because we want to avoid floating-point operations in the kernel,
+ * the events are all reported in fixed point arithmetic (32.32).
+ * Tools must adjust the counts to convert them to Watts using
+ * the duration of the measurement. Tools may use a function such as
+ * ldexp(raw_count, -32);
+ */
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/perf_event.h>
+#include <asm/cpu_device_id.h>
+#include "perf_event.h"
+
+/*
+ * RAPL energy status counters
+ */
+#define RAPL_IDX_PP0_NRG_STAT 0 /* all cores */
+#define INTEL_RAPL_PP0 0x1 /* pseudo-encoding */
+#define RAPL_IDX_PKG_NRG_STAT 1 /* entire package */
+#define INTEL_RAPL_PKG 0x2 /* pseudo-encoding */
+#define RAPL_IDX_RAM_NRG_STAT 2 /* DRAM */
+#define INTEL_RAPL_RAM 0x3 /* pseudo-encoding */
+
+/* Clients have PP0, PKG */
+#define RAPL_IDX_CLN (1<<RAPL_IDX_PP0_NRG_STAT|\
+ 1<<RAPL_IDX_PKG_NRG_STAT)
+
+/* Servers have PP0, PKG, RAM */
+#define RAPL_IDX_SRV (1<<RAPL_IDX_PP0_NRG_STAT|\
+ 1<<RAPL_IDX_PKG_NRG_STAT|\
+ 1<<RAPL_IDX_RAM_NRG_STAT)
+
+/*
+ * event code: LSB 8 bits, passed in attr->config
+ * any other bit is reserved
+ */
+#define RAPL_EVENT_MASK 0xFFULL
+
+#define DEFINE_RAPL_FORMAT_ATTR(_var, _name, _format) \
+static ssize_t __rapl_##_var##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, \
+ char *page) \
+{ \
+ BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE); \
+ return sprintf(page, _format "\n"); \
+} \
+static struct kobj_attribute format_attr_##_var = \
+ __ATTR(_name, 0444, __rapl_##_var##_show, NULL)
+
+#define RAPL_EVENT_DESC(_name, _config) \
+{ \
+ .attr = __ATTR(_name, 0444, rapl_event_show, NULL), \
+ .config = _config, \
+}
+
+#define RAPL_CNTR_WIDTH 32 /* 32-bit rapl counters */
+
+struct rapl_pmu {
+ spinlock_t lock;
+ int hw_unit; /* 1/2^hw_unit Joule */
+ int n_active; /* number of active events */
+ struct list_head active_list;
+ struct pmu *pmu; /* pointer to rapl_pmu_class */
+};
+
+static struct pmu rapl_pmu_class;
+static cpumask_t rapl_cpu_mask;
+static int rapl_cntr_mask;
+
+static DEFINE_PER_CPU(struct rapl_pmu *, rapl_pmu);
+static DEFINE_PER_CPU(struct rapl_pmu *, rapl_pmu_to_free);
+
+static inline u64 rapl_read_counter(struct perf_event *event)
+{
+ u64 raw;
+ rdmsrl(event->hw.event_base, raw);
+ return raw;
+}
+
+static inline u64 rapl_scale(u64 v)
+{
+ /*
+ * scale delta to smallest unit (1/2^32)
+ * users must then scale back: count * 1/(1e9*2^32) to get Joules
+ * or use ldexp(count, -32).
+ * Watts = Joules/Time delta
+ */
+ return v << (32 - __get_cpu_var(rapl_pmu)->hw_unit);
+}
+
+static u64 rapl_event_update(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ u64 prev_raw_count, new_raw_count;
+ s64 delta, sdelta;
+ int shift = RAPL_CNTR_WIDTH;
+
+again:
+ prev_raw_count = local64_read(&hwc->prev_count);
+ rdmsrl(event->hw.event_base, new_raw_count);
+
+ if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+ new_raw_count) != prev_raw_count) {
+ cpu_relax();
+ goto again;
+ }
+
+ /*
+ * Now we have the new raw value and have updated the prev
+ * timestamp already. We can now calculate the elapsed delta
+ * (event-)time and add that to the generic event.
+ *
+ * Careful, not all hw sign-extends above the physical width
+ * of the count.
+ */
+ delta = (new_raw_count << shift) - (prev_raw_count << shift);
+ delta >>= shift;
+
+ sdelta = rapl_scale(delta);
+
+ local64_add(sdelta, &event->count);
+
+ return new_raw_count;
+}
+
+static void __rapl_pmu_event_start(struct rapl_pmu *pmu,
+ struct perf_event *event)
+{
+ if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
+ return;
+
+ event->hw.state = 0;
+
+ list_add_tail(&event->active_entry, &pmu->active_list);
+
+ local64_set(&event->hw.prev_count, rapl_read_counter(event));
+
+ pmu->n_active++;
+}
+
+static void rapl_pmu_event_start(struct perf_event *event, int mode)
+{
+ struct rapl_pmu *pmu = __get_cpu_var(rapl_pmu);
+ unsigned long flags;
+
+ spin_lock_irqsave(&pmu->lock, flags);
+ __rapl_pmu_event_start(pmu, event);
+ spin_unlock_irqrestore(&pmu->lock, flags);
+}
+
+static void rapl_pmu_event_stop(struct perf_event *event, int mode)
+{
+ struct rapl_pmu *pmu = __get_cpu_var(rapl_pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pmu->lock, flags);
+
+ /* mark event as deactivated and stopped */
+ if (!(hwc->state & PERF_HES_STOPPED)) {
+ WARN_ON_ONCE(pmu->n_active <= 0);
+ pmu->n_active--;
+
+ list_del(&event->active_entry);
+
+ WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
+ hwc->state |= PERF_HES_STOPPED;
+ }
+
+ /* check if update of sw counter is necessary */
+ if ((mode & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
+ /*
+ * Drain the remaining delta count out of a event
+ * that we are disabling:
+ */
+ rapl_event_update(event);
+ hwc->state |= PERF_HES_UPTODATE;
+ }
+
+ spin_unlock_irqrestore(&pmu->lock, flags);
+}
+
+static int rapl_pmu_event_add(struct perf_event *event, int mode)
+{
+ struct rapl_pmu *pmu = __get_cpu_var(rapl_pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pmu->lock, flags);
+
+ hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+
+ if (mode & PERF_EF_START)
+ __rapl_pmu_event_start(pmu, event);
+
+ spin_unlock_irqrestore(&pmu->lock, flags);
+
+ return 0;
+}
+
+static void rapl_pmu_event_del(struct perf_event *event, int flags)
+{
+ rapl_pmu_event_stop(event, PERF_EF_UPDATE);
+}
+
+static int rapl_pmu_event_init(struct perf_event *event)
+{
+ u64 cfg = event->attr.config & RAPL_EVENT_MASK;
+ int bit, msr, ret = 0;
+
+ /* only look at RAPL events */
+ if (event->attr.type != rapl_pmu_class.type)
+ return -ENOENT;
+
+ /* check only supported bits are set */
+ if (event->attr.config & ~RAPL_EVENT_MASK)
+ return -EINVAL;
+
+ /*
+ * check event is known (determines counter)
+ */
+ switch (cfg) {
+ case INTEL_RAPL_PP0:
+ bit = RAPL_IDX_PP0_NRG_STAT;
+ msr = MSR_PP0_ENERGY_STATUS;
+ break;
+ case INTEL_RAPL_PKG:
+ bit = RAPL_IDX_PKG_NRG_STAT;
+ msr = MSR_PKG_ENERGY_STATUS;
+ break;
+ case INTEL_RAPL_RAM:
+ bit = RAPL_IDX_RAM_NRG_STAT;
+ msr = MSR_DRAM_ENERGY_STATUS;
+ break;
+ default:
+ return -EINVAL;
+ }
+ /* check event supported */
+ if (!(rapl_cntr_mask & (1 << bit)))
+ return -EINVAL;
+
+ /* unsupported modes and filters */
+ if (event->attr.exclude_user ||
+ event->attr.exclude_kernel ||
+ event->attr.exclude_hv ||
+ event->attr.exclude_idle ||
+ event->attr.exclude_host ||
+ event->attr.exclude_guest ||
+ event->attr.sample_period) /* no sampling */
+ return -EINVAL;
+
+ /* must be done before validate_group */
+ event->hw.event_base = msr;
+ event->hw.config = cfg;
+ event->hw.idx = bit;
+
+ return ret;
+}
+
+static void rapl_pmu_event_read(struct perf_event *event)
+{
+ rapl_event_update(event);
+}
+
+static ssize_t rapl_get_attr_cpumask(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int n = cpulist_scnprintf(buf, PAGE_SIZE - 2, &rapl_cpu_mask);
+
+ buf[n++] = '\n';
+ buf[n] = '\0';
+ return n;
+}
+
+static DEVICE_ATTR(cpumask, S_IRUGO, rapl_get_attr_cpumask, NULL);
+
+static struct attribute *rapl_pmu_attrs[] = {
+ &dev_attr_cpumask.attr,
+ NULL,
+};
+
+static struct attribute_group rapl_pmu_attr_group = {
+ .attrs = rapl_pmu_attrs,
+};
+
+EVENT_ATTR_STR(energy-cores, rapl_cores, "event=0x01");
+EVENT_ATTR_STR(energy-pkg , rapl_pkg, "event=0x02");
+EVENT_ATTR_STR(energy-ram , rapl_ram, "event=0x03");
+
+EVENT_ATTR_STR(energy-cores.unit, rapl_cores_unit, "Joules");
+EVENT_ATTR_STR(energy-pkg.unit , rapl_pkg_unit, "Joules");
+EVENT_ATTR_STR(energy-ram.unit , rapl_ram_unit, "Joules");
+
+/*
+ * we compute in 0.23 nJ increments regardless of MSR
+ */
+EVENT_ATTR_STR(energy-cores.scale, rapl_cores_scale, "2.3283064365386962890625e-10");
+EVENT_ATTR_STR(energy-pkg.scale, rapl_pkg_scale, "2.3283064365386962890625e-10");
+EVENT_ATTR_STR(energy-ram.scale, rapl_ram_scale, "2.3283064365386962890625e-10");
+
+static struct attribute *rapl_events_srv_attr[] = {
+ EVENT_PTR(rapl_cores),
+ EVENT_PTR(rapl_pkg),
+ EVENT_PTR(rapl_ram),
+
+ EVENT_PTR(rapl_cores_unit),
+ EVENT_PTR(rapl_pkg_unit),
+ EVENT_PTR(rapl_ram_unit),
+
+ EVENT_PTR(rapl_cores_scale),
+ EVENT_PTR(rapl_pkg_scale),
+ EVENT_PTR(rapl_ram_scale),
+ NULL,
+};
+
+static struct attribute *rapl_events_cln_attr[] = {
+ EVENT_PTR(rapl_cores),
+ EVENT_PTR(rapl_pkg),
+
+ EVENT_PTR(rapl_cores_unit),
+ EVENT_PTR(rapl_pkg_unit),
+
+ EVENT_PTR(rapl_cores_scale),
+ EVENT_PTR(rapl_pkg_scale),
+ NULL,
+};
+
+static struct attribute_group rapl_pmu_events_group = {
+ .name = "events",
+ .attrs = NULL, /* patched at runtime */
+};
+
+DEFINE_RAPL_FORMAT_ATTR(event, event, "config:0-7");
+static struct attribute *rapl_formats_attr[] = {
+ &format_attr_event.attr,
+ NULL,
+};
+
+static struct attribute_group rapl_pmu_format_group = {
+ .name = "format",
+ .attrs = rapl_formats_attr,
+};
+
+const struct attribute_group *rapl_attr_groups[] = {
+ &rapl_pmu_attr_group,
+ &rapl_pmu_format_group,
+ &rapl_pmu_events_group,
+ NULL,
+};
+
+static struct pmu rapl_pmu_class = {
+ .attr_groups = rapl_attr_groups,
+ .task_ctx_nr = perf_invalid_context, /* system-wide only */
+ .event_init = rapl_pmu_event_init,
+ .add = rapl_pmu_event_add, /* must have */
+ .del = rapl_pmu_event_del, /* must have */
+ .start = rapl_pmu_event_start,
+ .stop = rapl_pmu_event_stop,
+ .read = rapl_pmu_event_read,
+};
+
+static void rapl_cpu_exit(int cpu)
+{
+ struct rapl_pmu *pmu = per_cpu(rapl_pmu, cpu);
+ int i, phys_id = topology_physical_package_id(cpu);
+ int target = -1;
+
+ /* find a new cpu on same package */
+ for_each_online_cpu(i) {
+ if (i == cpu)
+ continue;
+ if (phys_id == topology_physical_package_id(i)) {
+ target = i;
+ break;
+ }
+ }
+ /*
+ * clear cpu from cpumask
+ * if was set in cpumask and still some cpu on package,
+ * then move to new cpu
+ */
+ if (cpumask_test_and_clear_cpu(cpu, &rapl_cpu_mask) && target >= 0)
+ cpumask_set_cpu(target, &rapl_cpu_mask);
+
+ WARN_ON(cpumask_empty(&rapl_cpu_mask));
+ /*
+ * migrate events and context to new cpu
+ */
+ if (target >= 0)
+ perf_pmu_migrate_context(pmu->pmu, cpu, target);
+}
+
+static void rapl_cpu_init(int cpu)
+{
+ int i, phys_id = topology_physical_package_id(cpu);
+
+ /* check if phys_is is already covered */
+ for_each_cpu(i, &rapl_cpu_mask) {
+ if (phys_id == topology_physical_package_id(i))
+ return;
+ }
+ /* was not found, so add it */
+ cpumask_set_cpu(cpu, &rapl_cpu_mask);
+}
+
+static int rapl_cpu_prepare(int cpu)
+{
+ struct rapl_pmu *pmu = per_cpu(rapl_pmu, cpu);
+ int phys_id = topology_physical_package_id(cpu);
+
+ if (pmu)
+ return 0;
+
+ if (phys_id < 0)
+ return -1;
+
+ pmu = kzalloc_node(sizeof(*pmu), GFP_KERNEL, cpu_to_node(cpu));
+ if (!pmu)
+ return -1;
+
+ spin_lock_init(&pmu->lock);
+
+ INIT_LIST_HEAD(&pmu->active_list);
+
+ /*
+ * grab power unit as: 1/2^unit Joules
+ *
+ * we cache in local PMU instance
+ */
+ rdmsrl(MSR_RAPL_POWER_UNIT, pmu->hw_unit);
+ pmu->hw_unit = (pmu->hw_unit >> 8) & 0x1FULL;
+ pmu->pmu = &rapl_pmu_class;
+
+ /* set RAPL pmu for this cpu for now */
+ per_cpu(rapl_pmu, cpu) = pmu;
+ per_cpu(rapl_pmu_to_free, cpu) = NULL;
+
+ return 0;
+}
+
+static void rapl_cpu_kfree(int cpu)
+{
+ struct rapl_pmu *pmu = per_cpu(rapl_pmu_to_free, cpu);
+
+ kfree(pmu);
+
+ per_cpu(rapl_pmu_to_free, cpu) = NULL;
+}
+
+static int rapl_cpu_dying(int cpu)
+{
+ struct rapl_pmu *pmu = per_cpu(rapl_pmu, cpu);
+
+ if (!pmu)
+ return 0;
+
+ per_cpu(rapl_pmu, cpu) = NULL;
+
+ per_cpu(rapl_pmu_to_free, cpu) = pmu;
+
+ return 0;
+}
+
+static int rapl_cpu_notifier(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (long)hcpu;
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_UP_PREPARE:
+ rapl_cpu_prepare(cpu);
+ break;
+ case CPU_STARTING:
+ rapl_cpu_init(cpu);
+ break;
+ case CPU_UP_CANCELED:
+ case CPU_DYING:
+ rapl_cpu_dying(cpu);
+ break;
+ case CPU_ONLINE:
+ case CPU_DEAD:
+ rapl_cpu_kfree(cpu);
+ break;
+ case CPU_DOWN_PREPARE:
+ rapl_cpu_exit(cpu);
+ break;
+ default:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static const struct x86_cpu_id rapl_cpu_match[] = {
+ [0] = { .vendor = X86_VENDOR_INTEL, .family = 6 },
+ [1] = {},
+};
+
+static int __init rapl_pmu_init(void)
+{
+ struct rapl_pmu *pmu;
+ int cpu, ret;
+
+ /*
+ * check for Intel processor family 6
+ */
+ if (!x86_match_cpu(rapl_cpu_match))
+ return 0;
+
+ /* check supported CPU */
+ switch (boot_cpu_data.x86_model) {
+ case 42: /* Sandy Bridge */
+ case 58: /* Ivy Bridge */
+ case 60: /* Haswell */
+ rapl_cntr_mask = RAPL_IDX_CLN;
+ rapl_pmu_events_group.attrs = rapl_events_cln_attr;
+ break;
+ case 45: /* Sandy Bridge-EP */
+ case 62: /* IvyTown */
+ rapl_cntr_mask = RAPL_IDX_SRV;
+ rapl_pmu_events_group.attrs = rapl_events_srv_attr;
+ break;
+
+ default:
+ /* unsupported */
+ return 0;
+ }
+ get_online_cpus();
+
+ for_each_online_cpu(cpu) {
+ rapl_cpu_prepare(cpu);
+ rapl_cpu_init(cpu);
+ }
+
+ perf_cpu_notifier(rapl_cpu_notifier);
+
+ ret = perf_pmu_register(&rapl_pmu_class, "power", -1);
+ if (WARN_ON(ret)) {
+ pr_info("RAPL PMU detected, registration failed (%d), RAPL PMU disabled\n", ret);
+ put_online_cpus();
+ return -1;
+ }
+
+ pmu = __get_cpu_var(rapl_pmu);
+
+ pr_info("RAPL PMU detected, hw unit 2^-%d Joules,"
+ " API unit is 2^-32 Joules,"
+ " %d fixed counters\n",
+ pmu->hw_unit,
+ hweight32(rapl_cntr_mask));
+
+ put_online_cpus();
+
+ return 0;
+}
+device_initcall(rapl_pmu_init);
projects / cascardo / linux.git / commitdiff