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perf/x86: Add Intel RAPL PMU support

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This patch adds a new uncore PMU to expose the Intel
RAPL energy consumption counters. Up to 3 counters,
each counting a particular RAPL event are exposed.

The RAPL counters are available on Intel SandyBridge,
IvyBridge, Haswell. The server skus add a 3rd counter.

The following events are available and exposed in sysfs:

  - power/energy-cores: power consumption of all cores on socket
  - power/energy-pkg: power consumption of all cores + LLc cache
  - power/energy-dram: power consumption of DRAM (servers only)

For each event both the unit (Joules) and scale (2^-32 J)
is exposed in sysfs for use by perf stat and other tools.
The files are:

	/sys/devices/power/events/energy-*.unit
	/sys/devices/power/events/energy-*.scale

The RAPL PMU is uncore by nature and is implemented such
that it only works in system-wide mode. Measuring only
one CPU per socket is sufficient. The /sys/devices/power/cpumask
file can be used by tools to figure out which CPUs to monitor
by default. For instance, on a 2-socket system, 2 CPUs
(one on each socket) will be shown.

All the counters measure in the same unit (exposed via sysfs).
The perf_events API exposes all RAPL counters as 64-bit integers
counting in unit of 1/2^32 Joules (about 0.23 nJ). User level tools
must convert the counts by multiplying them by 2^-32 to obtain
Joules. The reason for this is that the kernel avoids
doing floating point math whenever possible because it is
expensive (user floating-point state must be saved). The method
used avoids kernel floating-point usage. There is no loss of
precision. Thanks to PeterZ for suggesting this approach.

To convert the raw count in Watt:
   W = C * 2.3 / (1e10 * time)
or ldexp(C, -32).

RAPL PMU is a new standalone PMU which registers with the
perf_event core subsystem. The PMU type (attr->type) is
dynamically allocated and is available from /sys/device/power/type.

Sampling is not supported by the RAPL PMU. There is no
privilege level filtering either.

Signed-off-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: zheng.z.yan@intel.com
Cc: bp@alien8.de
Link: http://lkml.kernel.org/r/1384275531-10892-4-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Stephane Eranian 2013-11-12 17:58:50 +01:00 committed by Ingo Molnar
parent 410136f5dd
commit 4788e5b4b2
2 changed files with 592 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/kernel/cpu/Makefile
View File

@ -36,7 +36,7 @@ obj-$(CONFIG_CPU_SUP_AMD) += perf_event_amd_iommu.o
endif
obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_p6.o perf_event_knc.o perf_event_p4.o
obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_lbr.o perf_event_intel_ds.o perf_event_intel.o
obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_uncore.o
obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_uncore.o perf_event_intel_rapl.o
endif

591
arch/x86/kernel/cpu/perf_event_intel_rapl.c Normal file
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@ -0,0 +1,591 @@
/*
* 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);