[tip:perf/core] perf/x86: Add an MSR PMU driver

tip-bot for Andy Lutomirski
2015-08-04T09:02:05Z

Commit-ID: b7b7c7821d932ba18ef6c8eafc8536066b4c2ef4
Gitweb: http://git.kernel.org/tip/b7b7c7821d932ba18ef6c8eafc8536066b4c2ef4
Author: Andy Lutomirski <luto@kernel.org>
AuthorDate: Mon, 20 Jul 2015 11:49:06 -0400
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 4 Aug 2015 10:17:00 +0200

perf/x86: Add an MSR PMU driver

This patch adds an MSR PMU to support free running MSR counters. Such
as time and freq related counters includes TSC, IA32_APERF, IA32_MPERF
and IA32_PPERF, but also SMI_COUNT.

The events are exposed in sysfs for use by perf stat and other tools.
The files are under /sys/devices/msr/events/

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Kan Liang <kan.liang@intel.com>
[ s/freq/msr/, added SMI_COUNT, fixed bugs. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: adrian.hunter@intel.com
Cc: dsahern@gmail.com
Cc: eranian@google.com
Cc: jolsa@kernel.org
Cc: mark.rutland@arm.com
Cc: namhyung@kernel.org
Link: http://lkml.kernel.org/r/1437407346-31186-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/cpu/Makefile | 2 +
arch/x86/kernel/cpu/perf_event_msr.c | 242 +++++++++++++++++++++++++++++++++++
2 files changed, 244 insertions(+)

diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index 9bff687..4eb065c 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_msr.o
+obj-$(CONFIG_CPU_SUP_AMD) += perf_event_msr.o
endif

diff --git a/arch/x86/kernel/cpu/perf_event_msr.c b/arch/x86/kernel/cpu/perf_event_msr.c
new file mode 100644
index 0000000..af216e9
--- /dev/null
+++ b/arch/x86/kernel/cpu/perf_event_msr.c
@@ -0,0 +1,242 @@
+#include <linux/perf_event.h>
+
+enum perf_msr_id {
+ PERF_MSR_TSC = 0,
+ PERF_MSR_APERF = 1,
+ PERF_MSR_MPERF = 2,
+ PERF_MSR_PPERF = 3,
+ PERF_MSR_SMI = 4,
+
+ PERF_MSR_EVENT_MAX,
+};
+
+struct perf_msr {
+ int id;
+ u64 msr;
+};
+
+static struct perf_msr msr[] = {
+ { PERF_MSR_TSC, 0 },
+ { PERF_MSR_APERF, MSR_IA32_APERF },
+ { PERF_MSR_MPERF, MSR_IA32_MPERF },
+ { PERF_MSR_PPERF, MSR_PPERF },
+ { PERF_MSR_SMI, MSR_SMI_COUNT },
+};
+
+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");
+PMU_EVENT_ATTR_STRING(smi, evattr_smi, "event=0x04");
+
+static struct attribute *events_attrs[PERF_MSR_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 msr_event_init(struct perf_event *event)
+{
+ u64 cfg = event->attr.config;
+
+ if (event->attr.type != event->pmu->type)
+ return -ENOENT;
+
+ if (cfg >= PERF_MSR_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 = msr[cfg].msr;
+ event->hw.config = cfg;
+
+ return 0;
+}
+
+static inline u64 msr_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 msr_event_update(struct perf_event *event)
+{
+ u64 prev, now;
+ s64 delta;
+
+ /* Careful, an NMI might modify the previous event value. */
+again:
+ prev = local64_read(&event->hw.prev_count);
+ now = msr_read_counter(event);
+
+ if (local64_cmpxchg(&event->hw.prev_count, prev, now) != prev)
+ goto again;
+
+ delta = now - prev;
+ if (unlikely(event->hw.event_base == MSR_SMI_COUNT)) {
+ delta <<= 32;
+ delta >>= 32; /* sign extend */
+ }
+ local64_add(now - prev, &event->count);
+}
+
+static void msr_event_start(struct perf_event *event, int flags)
+{
+ u64 now;
+
+ now = msr_read_counter(event);
+ local64_set(&event->hw.prev_count, now);
+}
+
+static void msr_event_stop(struct perf_event *event, int flags)
+{
+ msr_event_update(event);
+}
+
+static void msr_event_del(struct perf_event *event, int flags)
+{
+ msr_event_stop(event, PERF_EF_UPDATE);
+}
+
+static int msr_event_add(struct perf_event *event, int flags)
+{
+ if (flags & PERF_EF_START)
+ msr_event_start(event, flags);
+
+ return 0;
+}
+
+static struct pmu pmu_msr = {
+ .task_ctx_nr = perf_sw_context,
+ .attr_groups = attr_groups,
+ .event_init = msr_event_init,
+ .add = msr_event_add,
+ .del = msr_event_del,
+ .start = msr_event_start,
+ .stop = msr_event_stop,
+ .read = msr_event_update,
+ .capabilities = PERF_PMU_CAP_NO_INTERRUPT,
+};
+
+static int __init intel_msr_init(int idx)
+{
+ if (boot_cpu_data.x86 != 6)
+ return 0;
+
+ switch (boot_cpu_data.x86_model) {
+ case 30: /* 45nm Nehalem */
+ case 26: /* 45nm Nehalem-EP */
+ case 46: /* 45nm Nehalem-EX */
+
+ case 37: /* 32nm Westmere */
+ case 44: /* 32nm Westmere-EP */
+ case 47: /* 32nm Westmere-EX */
+
+ case 42: /* 32nm SandyBridge */
+ case 45: /* 32nm SandyBridge-E/EN/EP */
+
+ case 58: /* 22nm IvyBridge */
+ case 62: /* 22nm IvyBridge-EP/EX */
+
+ case 60: /* 22nm Haswell Core */
+ case 63: /* 22nm Haswell Server */
+ case 69: /* 22nm Haswell ULT */
+ case 70: /* 22nm Haswell + GT3e (Intel Iris Pro graphics) */
+
+ case 61: /* 14nm Broadwell Core-M */
+ case 86: /* 14nm Broadwell Xeon D */
+ case 71: /* 14nm Broadwell + GT3e (Intel Iris Pro graphics) */
+ case 79: /* 14nm Broadwell Server */
+ events_attrs[idx++] = &evattr_smi.attr.attr;
+ break;
+
+ case 78: /* 14nm Skylake Mobile */
+ case 94: /* 14nm Skylake Desktop */
+ events_attrs[idx++] = &evattr_pperf.attr.attr;
+ events_attrs[idx++] = &evattr_smi.attr.attr;
+ break;
+
+ case 55: /* 22nm Atom "Silvermont" */
+ case 76: /* 14nm Atom "Airmont" */
+ case 77: /* 22nm Atom "Silvermont Avoton/Rangely" */
+ events_attrs[idx++] = &evattr_smi.attr.attr;
+ break;
+ }
+
+ events_attrs[idx] = NULL;
+
+ return 0;
+}
+
+static int __init amd_msr_init(int idx)
+{
+ return 0;
+}
+
+static int __init msr_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;
+ events_attrs[idx] = NULL;
+ }
+
+ switch (boot_cpu_data.x86_vendor) {
+ case X86_VENDOR_INTEL:
+ err = intel_msr_init(idx);
+ break;
+
+ case X86_VENDOR_AMD:
+ err = amd_msr_init(idx);
+ break;
+
+ default:
+ err = -ENOTSUPP;
+ }
+
+ if (err != 0) {
+ pr_cont("no msr PMU driver.\n");
+ return 0;
+ }
+
+ perf_pmu_register(&pmu_msr, "msr", -1);
+
+ return 0;
+}
+device_initcall(msr_init);