Making hardware events translations available through the sysfs.
Adding 'events' group attribute under the sysfs x86 PMU record
with attribute/file for each hardware event:
# ls /sys/devices/cpu/events/
branch-instructions
branch-misses
bus-cycles
cache-misses
cache-references
cpu-cycles
instructions
ref-cycles
stalled-cycles-backend
stalled-cycles-frontend
The file - hw event ID mappings is:
file hw event ID
---------------------------------------------------------------
cpu-cycles PERF_COUNT_HW_CPU_CYCLES
instructions PERF_COUNT_HW_INSTRUCTIONS
cache-references PERF_COUNT_HW_CACHE_REFERENCES
cache-misses PERF_COUNT_HW_CACHE_MISSES
branch-instructions PERF_COUNT_HW_BRANCH_INSTRUCTIONS
branch-misses PERF_COUNT_HW_BRANCH_MISSES
bus-cycles PERF_COUNT_HW_BUS_CYCLES
stalled-cycles-frontend PERF_COUNT_HW_STALLED_CYCLES_FRONTEND
stalled-cycles-backend PERF_COUNT_HW_STALLED_CYCLES_BACKEND
ref-cycles PERF_COUNT_HW_REF_CPU_CYCLES
Each file in 'events' directory contains term translation for the
symbolic hw event for the currently running cpu model.
# cat /sys/devices/cpu/events/stalled-cycles-backend
event=0xb1,umask=0x01,inv,cmask=0x01
Suggested-by: Peter Zijlstra <a.p.zijls...@chello.nl>
Signed-off-by: Jiri Olsa <jo...@redhat.com>
---
arch/x86/kernel/cpu/perf_event.c | 74 ++++++++++++++++++++++++++++++++++++++
1 file changed, 74 insertions(+)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 29557aa..09452c2 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1638,9 +1638,83 @@ static struct attribute_group x86_pmu_attr_group = {
.attrs = x86_pmu_attrs,
};
+static ssize_t event_sysfs_data(char *page, u64 config)
+{
+ u64 event = (config & ARCH_PERFMON_EVENTSEL_EVENT) |
+ (config & AMD64_EVENTSEL_EVENT) >> 24;
+ u64 umask = (config & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
+ u64 inv = (config & ARCH_PERFMON_EVENTSEL_INV) >> 23;
+ u64 cmask = (config & ARCH_PERFMON_EVENTSEL_CMASK) >> 24;
+ ssize_t ret;
+
+ /*
+ * We have whole page size to spend and just little data
+ * to write, so we can safely use sprintf.
+ */
+ ret = sprintf(page, "event=0x%02llx", event);
+
+ if (umask)
+ ret += sprintf(page + ret, ",umask=0x%02llx", umask);
+
+ if (inv)
+ ret += sprintf(page + ret, ",inv");
+
+ if (cmask)
+ ret += sprintf(page + ret, ",cmask=0x%02llx", cmask);
+
+ ret += sprintf(page + ret, "\n");
+
+ return ret;
+}
+
+#define PMU_EVENTS_ATTR(_name, _id) \
+static ssize_t \
+_id##_show(struct device *dev, \
+ struct device_attribute *attr, \
+ char *page) \
+{ \
+ u64 config = x86_pmu.event_map(_id); \
+ BUILD_BUG_ON(_id >= PERF_COUNT_HW_MAX); \
+ return event_sysfs_data(page, config); \
+} \
+ \
+static struct device_attribute event_attr_##_id = \
+ __ATTR(_name, 0444, _id##_show, NULL)
+
+PMU_EVENTS_ATTR(cpu-cycles, PERF_COUNT_HW_CPU_CYCLES);
+PMU_EVENTS_ATTR(instructions, PERF_COUNT_HW_INSTRUCTIONS);
+PMU_EVENTS_ATTR(cache-references, PERF_COUNT_HW_CACHE_REFERENCES);
+PMU_EVENTS_ATTR(cache-misses, PERF_COUNT_HW_CACHE_MISSES);
+PMU_EVENTS_ATTR(branch-instructions, PERF_COUNT_HW_BRANCH_INSTRUCTIONS);
+PMU_EVENTS_ATTR(branch-misses, PERF_COUNT_HW_BRANCH_MISSES);
+PMU_EVENTS_ATTR(bus-cycles, PERF_COUNT_HW_BUS_CYCLES);
+PMU_EVENTS_ATTR(stalled-cycles-frontend,
PERF_COUNT_HW_STALLED_CYCLES_FRONTEND);
+PMU_EVENTS_ATTR(stalled-cycles-backend, PERF_COUNT_HW_STALLED_CYCLES_BACKEND);
+PMU_EVENTS_ATTR(ref-cycles, PERF_COUNT_HW_REF_CPU_CYCLES);
+
+static struct attribute *events_attr[] = {
+ &event_attr_PERF_COUNT_HW_CPU_CYCLES.attr,
+ &event_attr_PERF_COUNT_HW_INSTRUCTIONS.attr,
+ &event_attr_PERF_COUNT_HW_CACHE_REFERENCES.attr,
+ &event_attr_PERF_COUNT_HW_CACHE_MISSES.attr,
+ &event_attr_PERF_COUNT_HW_BRANCH_INSTRUCTIONS.attr,
+ &event_attr_PERF_COUNT_HW_BRANCH_MISSES.attr,
+ &event_attr_PERF_COUNT_HW_BUS_CYCLES.attr,
+ &event_attr_PERF_COUNT_HW_STALLED_CYCLES_FRONTEND.attr,
+ &event_attr_PERF_COUNT_HW_STALLED_CYCLES_BACKEND.attr,
+ &event_attr_PERF_COUNT_HW_REF_CPU_CYCLES.attr,
+ NULL,
+};
+
+static struct attribute_group x86_pmu_events_group = {
+ .name = "events",
+ .attrs = events_attr,
+};
+
static const struct attribute_group *x86_pmu_attr_groups[] = {
&x86_pmu_attr_group,
&x86_pmu_format_group,
+ &x86_pmu_events_group,
NULL,
};
--
1.7.10.4
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