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

Signed-off-by: Agustin Vega-Frias <agust...@codeaurora.org>
---
 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.

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