Messages in this thread Patch in this message | | | From | Kan Liang <> | Subject | [PATCH RFC V2 1/1] x86, perf: Add a freq pmu driver | Date | Mon, 20 Jul 2015 11:49:06 -0400 |
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From: Andy Lutomirski <luto@kernel.org>
This patch adds freq PMU to support time and freq related counters includes TSC, IA32_APERF, IA32_MPERF and IA32_PPERF.
The events are exposed in sysfs for use by perf stat and other tools. The files are under /sys/devices/freq/events/
These events only support system-wide mode counting.
The PMU type (attr->type) is PERF_TYPE_FREQ.
Example:
To caculate the CPU% CPU_Utilization = CPU_CLK_UNHALTED.REF_TSC / TSC
$ perf stat -e '{ref-cycles,freq/tsc/}' -C0 -- taskset -c 0 sleep 1 3164023,,ref-cycles,1048387386,100.00 2410812089,,freq/tsc/,1050022373,100.00 The CPU% for sleep is 0.13%.
$ perf stat -e '{ref-cycles,freq/tsc/}' -C0 -- taskset -c 0 busyloop 15662183572,,ref-cycles,6822637855,100.00 15667608992,,freq/tsc/,6823978523,100.00 The CPU% for busy loop is 99.9%.
Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Kan Liang <kan.liang@intel.com> ---
The patch is based on the patch "x86, perf: Add an aperfmperf driver" from Andy Lutomirski (https://lkml.org/lkml/2015/4/28/757)
Changes from V1 - Change the name from aperfmperf to freq - Add TSC and PPERF support - Change to perf_sw_context - Assign new PERF_TYPE name - Split stop_or_del to two functions - Update state of hw_perf_event - Update changlog
arch/x86/kernel/cpu/Makefile | 2 + arch/x86/kernel/cpu/perf_event_freq.c | 207 ++++++++++++++++++++++++++++++++++ include/uapi/linux/perf_event.h | 1 + 3 files changed, 210 insertions(+) create mode 100644 arch/x86/kernel/cpu/perf_event_freq.c
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index 9bff687..f621dba 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -46,6 +46,8 @@ obj-$(CONFIG_PERF_EVENTS_INTEL_UNCORE) += perf_event_intel_uncore.o \ perf_event_intel_uncore_snb.o \ perf_event_intel_uncore_snbep.o \ perf_event_intel_uncore_nhmex.o +obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_freq.o +obj-$(CONFIG_CPU_SUP_AMD) += perf_event_freq.o endif diff --git a/arch/x86/kernel/cpu/perf_event_freq.c b/arch/x86/kernel/cpu/perf_event_freq.c new file mode 100644 index 0000000..9389b3b --- /dev/null +++ b/arch/x86/kernel/cpu/perf_event_freq.c @@ -0,0 +1,207 @@ +#include <linux/perf_event.h> + +enum perf_freq_id { + /* + * freq events, generalized by the kernel: + */ + PERF_FREQ_TSC = 0, + PERF_FREQ_APERF = 1, + PERF_FREQ_MPERF = 2, + PERF_FREQ_PPERF = 3, + + PERF_FREQ_EVENT_MAX, /* non-ABI */ +}; + +struct perf_freq_msr { + int id; + u64 msr; +}; + +static struct perf_freq_msr freq_msr[] = { + { PERF_FREQ_TSC, 0 }, + { PERF_FREQ_APERF, MSR_IA32_APERF }, + { PERF_FREQ_MPERF, MSR_IA32_MPERF }, + { PERF_FREQ_PPERF, MSR_PPERF }, +}; + + + +PMU_EVENT_ATTR_STRING(tsc, evattr_tsc, "event=0x00"); +PMU_EVENT_ATTR_STRING(aperf, evattr_aperf, "event=0x01"); +PMU_EVENT_ATTR_STRING(mperf, evattr_mperf, "event=0x02"); +PMU_EVENT_ATTR_STRING(pperf, evattr_pperf, "event=0x03"); + +static struct attribute *events_attrs[PERF_FREQ_EVENT_MAX + 1] = { + &evattr_tsc.attr.attr, +}; + +static struct attribute_group events_attr_group = { + .name = "events", + .attrs = events_attrs, +}; + +PMU_FORMAT_ATTR(event, "config:0-63"); +static struct attribute *format_attrs[] = { + &format_attr_event.attr, + NULL, +}; +static struct attribute_group format_attr_group = { + .name = "format", + .attrs = format_attrs, +}; + +static const struct attribute_group *attr_groups[] = { + &events_attr_group, + &format_attr_group, + NULL, +}; + +static int freq_event_init(struct perf_event *event) +{ + u64 cfg = event->attr.config; + + if (event->attr.type != event->pmu->type) + return -ENOENT; + + if (cfg >= PERF_FREQ_EVENT_MAX) + 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; + + event->hw.idx = -1; + event->hw.event_base = freq_msr[cfg].msr; + event->hw.config = cfg; + + return 0; +} + +static inline u64 freq_read_counter(struct perf_event *event) +{ + u64 now; + + if (event->hw.event_base) + rdmsrl(event->hw.event_base, now); + else + now = rdtsc(); + + return now; +} +static void freq_event_update(struct perf_event *event) +{ + u64 prev; + u64 now; + + /* Assume counters are 64bit */ + now = freq_read_counter(event); + prev = local64_xchg(&event->hw.prev_count, now); + local64_add(now - prev, &event->count); +} + +static void freq_event_start(struct perf_event *event, int flags) +{ + u64 now; + + now = freq_read_counter(event); + local64_set(&event->hw.prev_count, now); +} + +static void freq_event_stop(struct perf_event *event, int flags) +{ + 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 update of sw counter is necessary */ + if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) { + freq_event_update(event); + hwc->state |= PERF_HES_UPTODATE; + } +} + +static void freq_event_del(struct perf_event *event, int flags) +{ + freq_event_stop(event, PERF_EF_UPDATE); +} + +static int freq_event_add(struct perf_event *event, int flags) +{ + struct hw_perf_event *hwc = &event->hw; + + hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED; + + if (flags & PERF_EF_START) + freq_event_start(event, flags); + + return 0; +} + +static struct pmu pmu_freq = { + .task_ctx_nr = perf_sw_context, + .attr_groups = attr_groups, + .event_init = freq_event_init, + .add = freq_event_add, + .del = freq_event_del, + .start = freq_event_start, + .stop = freq_event_stop, + .read = freq_event_update, + .capabilities = PERF_PMU_CAP_NO_INTERRUPT, +}; + +static int __init intel_freq_specific_init(int idx) +{ + /* Skylake has pperf support */ + if ((boot_cpu_data.x86_model == 78) || + (boot_cpu_data.x86_model == 94)) + events_attrs[idx++] = &evattr_pperf.attr.attr; + + events_attrs[idx++] = NULL; + + return 0; +} + +static int __init amd_freq_specific_init(int idx) +{ + return 0; +} + +static int __init freq_init(void) +{ + int err; + int idx = 1; + + if (boot_cpu_has(X86_FEATURE_APERFMPERF)) { + events_attrs[idx++] = &evattr_aperf.attr.attr; + events_attrs[idx++] = &evattr_mperf.attr.attr; + } + + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_INTEL: + err = intel_freq_specific_init(idx); + break; + case X86_VENDOR_AMD: + err = amd_freq_specific_init(idx); + break; + default: + err = -ENOTSUPP; + } + + if (err != 0) { + pr_cont("no freq PMU driver.\n"); + return 0; + } + + perf_pmu_register(&pmu_freq, "freq", PERF_TYPE_FREQ); + + return 0; +} +device_initcall(freq_init); diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index d97f84c..1f8c400 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -32,6 +32,7 @@ enum perf_type_id { PERF_TYPE_HW_CACHE = 3, PERF_TYPE_RAW = 4, PERF_TYPE_BREAKPOINT = 5, + PERF_TYPE_FREQ = 6, PERF_TYPE_MAX, /* non-ABI */ }; -- 1.8.3.1
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