[RFC V3 2/3] perf, tools: Display pmu name when printing unmerged events in stat

From: Agustin Vega-Frias
Date: Tue Mar 06 2018 - 09:05:39 EST


To simplify creation of events accross multiple instances of the same type
of PMU stat supports two methods for creating multiple events from a single
event specification:
1. A prefix or glob can be used in the PMU name.
2. Aliases, which are listed immediately after the Kernel PMU events
by perf list, are used.

When the --no-merge option is passed and these events are displayed
individually the PMU name is lost and it's not possible to see which
count corresponds to which pmu:

$ ./perf stat -a -e l3cache/read-miss/ --no-merge ls > /dev/null

Performance counter stats for 'system wide':

67 l3cache/read-miss/
67 l3cache/read-miss/
63 l3cache/read-miss/
60 l3cache/read-miss/

0.001675706 seconds time elapsed

$ ./perf stat -a -e l3cache_read_miss --no-merge ls > /dev/null

Performance counter stats for 'system wide':

12 l3cache_read_miss
17 l3cache_read_miss
10 l3cache_read_miss
8 l3cache_read_miss

0.001661305 seconds time elapsed

This change adds the original pmu name to the event. For dynamic pmu
events the pmu name is restored in the event name:

$ ./perf stat -a -e l3cache/read-miss/ --no-merge ls > /dev/null

Performance counter stats for 'system wide':

63 l3cache_0_3/read-miss/
74 l3cache_0_1/read-miss/
64 l3cache_0_2/read-miss/
74 l3cache_0_0/read-miss/

0.001675706 seconds time elapsed

For alias events the name is added after the event name:

$ ./perf stat -a -e l3cache_read_miss --no-merge ls > /dev/null

Performance counter stats for 'system wide':

10 l3cache_read_miss [l3cache_0_3]
12 l3cache_read_miss [l3cache_0_1]
10 l3cache_read_miss [l3cache_0_2]
17 l3cache_read_miss [l3cache_0_0]

0.001661305 seconds time elapsed

Change-Id: I8056b9eda74bda33e95065056167ad96e97cb1fb
Signed-off-by: Agustin Vega-Frias <agustinv@xxxxxxxxxxxxxx>
---
tools/perf/builtin-stat.c | 29 ++++++++++++++++++++++++++++-
tools/perf/util/evsel.c | 1 +
tools/perf/util/evsel.h | 1 +
tools/perf/util/parse-events.c | 8 +++++++-
4 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 98bf9d3..d196972 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1225,6 +1225,31 @@ static void aggr_update_shadow(void)
}
}

+static void uniquify_event_name(struct perf_evsel *counter)
+{
+ char *new_name;
+ char *config;
+
+ if (!counter->pmu_name || !strncmp(counter->name, counter->pmu_name,
+ strlen(counter->pmu_name)))
+ return;
+
+ config = strchr(counter->name, '/');
+ if (config) {
+ if (asprintf(&new_name,
+ "%s%s", counter->pmu_name, config) > 0) {
+ free(counter->name);
+ counter->name = new_name;
+ }
+ } else {
+ if (asprintf(&new_name,
+ "%s [%s]", counter->name, counter->pmu_name) > 0) {
+ free(counter->name);
+ counter->name = new_name;
+ }
+ }
+}
+
static void collect_all_aliases(struct perf_evsel *counter,
void (*cb)(struct perf_evsel *counter, void *data,
bool first),
@@ -1253,7 +1278,9 @@ static bool collect_data(struct perf_evsel *counter,
if (counter->merged_stat)
return false;
cb(counter, data, true);
- if (!no_merge && counter->auto_merge_stats)
+ if (no_merge)
+ uniquify_event_name(counter);
+ else if (counter->auto_merge_stats)
collect_all_aliases(counter, cb, data);
return true;
}
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index ef35168..4841000 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -244,6 +244,7 @@ void perf_evsel__init(struct perf_evsel *evsel,
evsel->metric_name = NULL;
evsel->metric_events = NULL;
evsel->collect_stat = false;
+ evsel->pmu_name = NULL;
}

struct perf_evsel *perf_evsel__new_idx(struct perf_event_attr *attr, int idx)
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index a7487c6..c2ac16a 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -142,6 +142,7 @@ struct perf_evsel {
struct perf_evsel **metric_events;
bool collect_stat;
bool weak_group;
+ const char *pmu_name;
};

union u64_swap {
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 34589c4..bafc91e 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1247,7 +1247,12 @@ static int __parse_events_add_pmu(struct parse_events_state *parse_state,
if (!head_config) {
attr.type = pmu->type;
evsel = __add_event(list, &parse_state->idx, &attr, NULL, pmu, NULL, auto_merge_stats);
- return evsel ? 0 : -ENOMEM;
+ if (evsel) {
+ evsel->pmu_name = name;
+ return 0;
+ } else {
+ return -ENOMEM;
+ }
}

if (perf_pmu__check_alias(pmu, head_config, &info))
@@ -1276,6 +1281,7 @@ static int __parse_events_add_pmu(struct parse_events_state *parse_state,
evsel->snapshot = info.snapshot;
evsel->metric_expr = info.metric_expr;
evsel->metric_name = info.metric_name;
+ evsel->pmu_name = name;
}

return evsel ? 0 : -ENOMEM;
--
Qualcomm Datacenter Technologies, Inc. on behalf of the Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.