[PATCH v6 2/2] perf/x86/amd/power: Add AMD accumulated power reporting mechanism
From: Huang Rui
Date: Thu Mar 03 2016 - 03:16:46 EST
Introduce an AMD accumlated power reporting mechanism for the Family
15h, Model 60h processor that can be used to calculate the average
power consumed by a processor during a measurement interval. The
feature support is indicated by CPUID Fn8000_0007_EDX[12].
This feature will be implemented both in hwmon and perf. The current
design provides one event to report per package/processor power
consumption by counting each compute unit power value.
Here the gory details of how the computation is done:
---------------------------------------------------------------------
* Tsample: compute unit power accumulator sample period
* Tref: the PTSC counter period (PTSC: performance timestamp counter)
* N: the ratio of compute unit power accumulator sample period to the
PTSC period
* Jmax: max compute unit accumulated power which is indicated by
MSR_C001007b[MaxCpuSwPwrAcc]
* Jx/Jy: compute unit accumulated power which is indicated by
MSR_C001007a[CpuSwPwrAcc]
* Tx/Ty: the value of performance timestamp counter which is indicated
by CU_PTSC MSR_C0010280[PTSC]
* PwrCPUave: CPU average power
i. Determine the ratio of Tsample to Tref by executing CPUID Fn8000_0007.
N = value of CPUID Fn8000_0007_ECX[CpuPwrSampleTimeRatio[15:0]].
ii. Read the full range of the cumulative energy value from the new
MSR MaxCpuSwPwrAcc.
Jmax = value returned.
iii. At time x, software reads CpuSwPwrAcc and samples the PTSC.
Jx = value read from CpuSwPwrAcc and Tx = value read from PTSC.
iv. At time y, software reads CpuSwPwrAcc and samples the PTSC.
Jy = value read from CpuSwPwrAcc and Ty = value read from PTSC.
v. Calculate the average power consumption for a compute unit over
time period (y-x). Unit of result is uWatt:
if (Jy < Jx) // Rollover has occurred
Jdelta = (Jy + Jmax) - Jx
else
Jdelta = Jy - Jx
PwrCPUave = N * Jdelta * 1000 / (Ty - Tx)
----------------------------------------------------------------------
Simple example:
root@hr-zp:/home/ray/tip# ./tools/perf/perf stat -a -e 'power/power-pkg/' make -j4
CHK include/config/kernel.release
CHK include/generated/uapi/linux/version.h
CHK include/generated/utsrelease.h
CHK include/generated/timeconst.h
CHK include/generated/bounds.h
CHK include/generated/asm-offsets.h
CALL scripts/checksyscalls.sh
CHK include/generated/compile.h
SKIPPED include/generated/compile.h
Building modules, stage 2.
Kernel: arch/x86/boot/bzImage is ready (#40)
MODPOST 4225 modules
Performance counter stats for 'system wide':
183.44 mWatts power/power-pkg/
341.837270111 seconds time elapsed
root@hr-zp:/home/ray/tip# ./tools/perf/perf stat -a -e 'power/power-pkg/' sleep 10
Performance counter stats for 'system wide':
0.18 mWatts power/power-pkg/
10.012551815 seconds time elapsed
Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Suggested-by: Ingo Molnar <mingo@xxxxxxxxxx>
Suggested-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
---
Hi Thomas,
Thanks to suggest the updates for power_cpu_init(), but there are some
minor issues with below codes.
target = cpumask_any_and(&cpu_mask, topology_sibling_cpumask(cpu));
if (target < nr_cpu_ids)
cpumask_set_cpu(cpu, &cpu_mask);
For example: cores number is 4, and compute unit number is 2 (2 cores
per compute units).
When amd_power_pmu completes initialization, the cpumask will be set
as 1111. Actually, I just would like to choose one core per compute
unit. So the expected value should be 0101.
when core 2 and core 3 are both online (they are in same compute
unit) and cpu_mask is 1111,
set core 2 offline, then 1111 -> 1011,
set core 2 online again, then 1011 -> 1111.
Actually, we don't expect two cores both set at cpu_mask in the same
compute unit.
So as inspired by you, I do below change for power_cpu_init and tested
in my platform, please see my codes. :-)
Thanks,
Rui
---
arch/x86/Kconfig | 9 +
arch/x86/kernel/cpu/Makefile | 1 +
arch/x86/kernel/cpu/perf_event_amd_power.c | 360 +++++++++++++++++++++++++++++
include/linux/perf_event.h | 4 +
4 files changed, 374 insertions(+)
create mode 100644 arch/x86/kernel/cpu/perf_event_amd_power.c
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 330e738..a0d3fb0 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1202,6 +1202,15 @@ config MICROCODE_OLD_INTERFACE
def_bool y
depends on MICROCODE
+config PERF_EVENTS_AMD_POWER
+ depends on PERF_EVENTS && CPU_SUP_AMD
+ tristate "AMD Processor Power Reporting Mechanism"
+ ---help---
+ Provide power reporting mechanism support for AMD processors.
+ Currently, it leverages X86_FEATURE_ACC_POWER
+ (CPUID Fn8000_0007_EDX[12]) interface to calculate the
+ average power consumption on Family 15h processors.
+
config X86_MSR
tristate "/dev/cpu/*/msr - Model-specific register support"
---help---
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index faa7b52..95d8419 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_PERF_EVENTS) += perf_event.o
ifdef CONFIG_PERF_EVENTS
obj-$(CONFIG_CPU_SUP_AMD) += perf_event_amd.o perf_event_amd_uncore.o
+obj-$(CONFIG_PERF_EVENTS_AMD_POWER) += perf_event_amd_power.o
ifdef CONFIG_AMD_IOMMU
obj-$(CONFIG_CPU_SUP_AMD) += perf_event_amd_iommu.o
endif
diff --git a/arch/x86/kernel/cpu/perf_event_amd_power.c b/arch/x86/kernel/cpu/perf_event_amd_power.c
new file mode 100644
index 0000000..42d5072
--- /dev/null
+++ b/arch/x86/kernel/cpu/perf_event_amd_power.c
@@ -0,0 +1,360 @@
+/*
+ * Performance events - AMD Processor Power Reporting Mechanism
+ *
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ *
+ * Author: Huang Rui <ray.huang@xxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/perf_event.h>
+#include <asm/cpu_device_id.h>
+#include "perf_event.h"
+
+#define MSR_F15H_CU_PWR_ACCUMULATOR 0xc001007a
+#define MSR_F15H_CU_MAX_PWR_ACCUMULATOR 0xc001007b
+#define MSR_F15H_PTSC 0xc0010280
+
+/* Event code: LSB 8 bits, passed in attr->config any other bit is reserved. */
+#define AMD_POWER_EVENT_MASK 0xFFULL
+
+/*
+ * Accumulated power status counters.
+ */
+#define AMD_POWER_EVENTSEL_PKG 1
+
+/*
+ * The ratio of compute unit power accumulator sample period to the
+ * PTSC period.
+ */
+static unsigned int cpu_pwr_sample_ratio;
+static unsigned int cu_num;
+
+/* Maximum accumulated power of a compute unit. */
+static u64 max_cu_acc_power;
+
+static struct pmu pmu_class;
+
+/*
+ * Accumulated power represents the sum of each compute unit's (CU) power
+ * consumption. On any core of each CU we read the total accumulated power from
+ * MSR_F15H_CU_PWR_ACCUMULATOR. cpu_mask represents CPU bit map of all cores
+ * which are picked to measure the power for the CUs they belong to.
+ */
+static cpumask_t cpu_mask;
+
+static void event_update(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ u64 prev_pwr_acc, new_pwr_acc, prev_ptsc, new_ptsc;
+ u64 delta, tdelta;
+
+ prev_pwr_acc = hwc->pwr_acc;
+ prev_ptsc = hwc->ptsc;
+ rdmsrl(MSR_F15H_CU_PWR_ACCUMULATOR, new_pwr_acc);
+ rdmsrl(MSR_F15H_PTSC, new_ptsc);
+
+ /*
+ * Calculate the CU power consumption over a time period, the unit of
+ * final value (delta) is micro-Watts. Then add it to the event count.
+ */
+ if (new_pwr_acc < prev_pwr_acc) {
+ delta = max_cu_acc_power + new_pwr_acc;
+ delta -= prev_pwr_acc;
+ } else
+ delta = new_pwr_acc - prev_pwr_acc;
+
+ delta *= cpu_pwr_sample_ratio * 1000;
+ tdelta = new_ptsc - prev_ptsc;
+
+ do_div(delta, tdelta);
+ local64_add(delta, &event->count);
+}
+
+static void __pmu_event_start(struct perf_event *event)
+{
+ if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
+ return;
+
+ event->hw.state = 0;
+
+ rdmsrl(MSR_F15H_PTSC, event->hw.ptsc);
+ rdmsrl(MSR_F15H_CU_PWR_ACCUMULATOR, event->hw.pwr_acc);
+}
+
+static void pmu_event_start(struct perf_event *event, int mode)
+{
+ __pmu_event_start(event);
+}
+
+static void pmu_event_stop(struct perf_event *event, int mode)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ /* Mark event as deactivated and stopped. */
+ if (!(hwc->state & PERF_HES_STOPPED))
+ hwc->state |= PERF_HES_STOPPED;
+
+ /* Check if software counter update is necessary. */
+ if ((mode & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
+ /*
+ * Drain the remaining delta count out of an event
+ * that we are disabling:
+ */
+ event_update(event);
+ hwc->state |= PERF_HES_UPTODATE;
+ }
+}
+
+static int pmu_event_add(struct perf_event *event, int mode)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+
+ if (mode & PERF_EF_START)
+ __pmu_event_start(event);
+
+ return 0;
+}
+
+static void pmu_event_del(struct perf_event *event, int flags)
+{
+ pmu_event_stop(event, PERF_EF_UPDATE);
+}
+
+static int pmu_event_init(struct perf_event *event)
+{
+ u64 cfg = event->attr.config & AMD_POWER_EVENT_MASK;
+
+ /* Only look at AMD power events. */
+ if (event->attr.type != pmu_class.type)
+ return -ENOENT;
+
+ /* 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 ||
+ /* no sampling */
+ event->attr.sample_period)
+ return -EINVAL;
+
+ if (cfg != AMD_POWER_EVENTSEL_PKG)
+ return -EINVAL;
+
+ return 0;
+}
+
+static void pmu_event_read(struct perf_event *event)
+{
+ event_update(event);
+}
+
+static ssize_t
+get_attr_cpumask(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return cpumap_print_to_pagebuf(true, buf, &cpu_mask);
+}
+
+static DEVICE_ATTR(cpumask, S_IRUGO, get_attr_cpumask, NULL);
+
+static struct attribute *pmu_attrs[] = {
+ &dev_attr_cpumask.attr,
+ NULL,
+};
+
+static struct attribute_group pmu_attr_group = {
+ .attrs = pmu_attrs,
+};
+
+/*
+ * Currently it only supports to report the power of each
+ * processor/package.
+ */
+EVENT_ATTR_STR(power-pkg, power_pkg, "event=0x01");
+
+EVENT_ATTR_STR(power-pkg.unit, power_pkg_unit, "mWatts");
+
+/* Convert the count from micro-Watts to milli-Watts. */
+EVENT_ATTR_STR(power-pkg.scale, power_pkg_scale, "1.000000e-3");
+
+static struct attribute *events_attr[] = {
+ EVENT_PTR(power_pkg),
+ EVENT_PTR(power_pkg_unit),
+ EVENT_PTR(power_pkg_scale),
+ NULL,
+};
+
+static struct attribute_group pmu_events_group = {
+ .name = "events",
+ .attrs = events_attr,
+};
+
+PMU_FORMAT_ATTR(event, "config:0-7");
+
+static struct attribute *formats_attr[] = {
+ &format_attr_event.attr,
+ NULL,
+};
+
+static struct attribute_group pmu_format_group = {
+ .name = "format",
+ .attrs = formats_attr,
+};
+
+static const struct attribute_group *attr_groups[] = {
+ &pmu_attr_group,
+ &pmu_format_group,
+ &pmu_events_group,
+ NULL,
+};
+
+static struct pmu pmu_class = {
+ .attr_groups = attr_groups,
+ /* system-wide only */
+ .task_ctx_nr = perf_invalid_context,
+ .event_init = pmu_event_init,
+ .add = pmu_event_add,
+ .del = pmu_event_del,
+ .start = pmu_event_start,
+ .stop = pmu_event_stop,
+ .read = pmu_event_read,
+};
+
+static void power_cpu_exit(int cpu)
+{
+ int target = nr_cpumask_bits;
+
+ if (!cpumask_test_and_clear_cpu(cpu, &cpu_mask))
+ return;
+
+ /*
+ * Find a new CPU on the same compute unit, if was set in cpumask
+ * and still some CPUs on compute unit. Then migrate event and
+ * context to new CPU.
+ */
+ target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu);
+ if (target < nr_cpumask_bits) {
+ cpumask_set_cpu(target, &cpu_mask);
+ perf_pmu_migrate_context(&pmu_class, cpu, target);
+ }
+}
+
+static void power_cpu_init(int cpu)
+{
+ /*
+ * 1) If any CPU is set at cpu_mask in the same compute unit, do
+ * nothing.
+ * 2) If no CPU is set at cpu_mask in the same compute unit,
+ * set current STARTING CPU.
+ *
+ * If cpu_mask and topology_sibling_cpumask has intersected
+ * bits, that means any CPU is set in the same compute unit.
+ * But cpumask_weight(topology_sibling_cpumask(cpu)) == 1
+ * means no CPU is set on cpu_mask in the same compute unit
+ * before init current STARTING CPU.
+ */
+ if (!cpumask_intersects(&cpu_mask, topology_sibling_cpumask(cpu)) &&
+ cpumask_weight(topology_sibling_cpumask(cpu)) == 1)
+ cpumask_set_cpu(cpu, &cpu_mask);
+}
+
+static int
+power_cpu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (long)hcpu;
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_STARTING:
+ power_cpu_init(cpu);
+ break;
+ case CPU_DOWN_PREPARE:
+ power_cpu_exit(cpu);
+ break;
+ default:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block power_cpu_notifier_nb = {
+ .notifier_call = power_cpu_notifier,
+ .priority = CPU_PRI_PERF,
+};
+
+static const struct x86_cpu_id cpu_match[] = {
+ { .vendor = X86_VENDOR_AMD, .family = 0x15 },
+ {},
+};
+
+static int __init amd_power_pmu_init(void)
+{
+ int i, ret;
+ u64 tmp;
+
+ if (!x86_match_cpu(cpu_match))
+ return 0;
+
+ if (!boot_cpu_has(X86_FEATURE_ACC_POWER))
+ return -ENODEV;
+
+ cu_num = boot_cpu_data.x86_max_cores / smp_num_siblings;
+
+ cpu_pwr_sample_ratio = cpuid_ecx(0x80000007);
+
+ if (rdmsrl_safe(MSR_F15H_CU_MAX_PWR_ACCUMULATOR, &tmp)) {
+ pr_err("Failed to read max compute unit power accumulator MSR\n");
+ return -ENODEV;
+ }
+ max_cu_acc_power = tmp;
+
+ cpu_notifier_register_begin();
+
+ /* Choose one online core of each compute unit. */
+ for (i = 0; i < boot_cpu_data.x86_max_cores; i += smp_num_siblings) {
+ WARN_ON(cpumask_empty(topology_sibling_cpumask(i)));
+ cpumask_set_cpu(cpumask_any(topology_sibling_cpumask(i)), &cpu_mask);
+ }
+
+ for_each_online_cpu(i)
+ power_cpu_init(i);
+
+ __register_cpu_notifier(&power_cpu_notifier_nb);
+
+ ret = perf_pmu_register(&pmu_class, "power", -1);
+ if (WARN_ON(ret)) {
+ pr_warn("AMD Power PMU registration failed\n");
+ goto out;
+ }
+
+ pr_info("AMD Power PMU detected, %d compute units\n", cu_num);
+
+out:
+ cpu_notifier_register_done();
+
+ return ret;
+}
+module_init(amd_power_pmu_init);
+
+static void __exit amd_power_pmu_exit(void)
+{
+ cpu_notifier_register_begin();
+ __unregister_cpu_notifier(&power_cpu_notifier_nb);
+ cpu_notifier_register_done();
+
+ perf_pmu_unregister(&pmu_class);
+}
+module_exit(amd_power_pmu_exit);
+
+MODULE_AUTHOR("Huang Rui <ray.huang@xxxxxxx>");
+MODULE_DESCRIPTION("AMD Processor Power Reporting Mechanism");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index f9828a4..01ea21c 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -128,6 +128,10 @@ struct hw_perf_event {
struct { /* itrace */
int itrace_started;
};
+ struct { /* amd_power */
+ u64 pwr_acc;
+ u64 ptsc;
+ };
#ifdef CONFIG_HAVE_HW_BREAKPOINT
struct { /* breakpoint */
/*
--
1.9.1