A metric like DRAM_BW_Use has on SkylakeX events uncore_imc/cas_count_read/ and uncore_imc/case_count_write/. These events open 6 events per socket with pmu names of uncore_imc_[0-5]. The current metric setup code in find_evsel_group assumes one ID will map to 1 event to be recorded in metric_events. For events with multiple matches, the first event is recorded in metric_events (avoiding matching >1 event with the same name) and the evlist_used updated so that duplicate events aren't removed when the evlist has unused events removed.
Before this change: $ /tmp/perf/perf stat -M DRAM_BW_Use -a -- sleep 1 Performance counter stats for 'system wide': 41.14 MiB uncore_imc/cas_count_read/ 1,002,614,251 ns duration_time 1.002614251 seconds time elapsed After this change: $ /tmp/perf/perf stat -M DRAM_BW_Use -a -- sleep 1 Performance counter stats for 'system wide': 157.47 MiB uncore_imc/cas_count_read/ # 0.00 DRAM_BW_Use 126.97 MiB uncore_imc/cas_count_write/ 1,003,019,728 ns duration_time v2. avoids iterating over the whole evlist as suggested by namhy...@kernel.org. It also fixes the metric_leader computation that was broken in the same commits. Erroneous duplication introduced in: commit 2440689d62e9 ("perf metricgroup: Remove duped metric group events"). Fixes: ded80bda8bc9 ("perf expr: Migrate expr ids table to a hashmap"). Reported-by: Jin Yao <yao....@linux.intel.com> Signed-off-by: Ian Rogers <irog...@google.com> --- tools/perf/util/metricgroup.c | 45 ++++++++++++++++++++++++++++++++--- 1 file changed, 42 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c index 662f4e8777d5..79080de9217d 100644 --- a/tools/perf/util/metricgroup.c +++ b/tools/perf/util/metricgroup.c @@ -206,6 +206,18 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist, sizeof(struct evsel *) * idnum); current_leader = ev->leader; } + /* + * Check for duplicate events with the same name. For example, + * uncore_imc/cas_count_read/ will turn into 6 events per socket + * on skylakex. Only the first such event is placed in + * metric_events. + */ + for (i = 0; i < matched_events; i++) { + if (!strcmp(metric_events[i]->name, ev->name)) + break; + } + if (i != matched_events) + continue; if (hashmap__find(&pctx->ids, ev->name, (void **)&val_ptr)) { if (has_constraint) { /* @@ -245,9 +257,36 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist, metric_events[idnum] = NULL; for (i = 0; i < idnum; i++) { - ev = metric_events[i]; - ev->metric_leader = ev; - set_bit(ev->idx, evlist_used); + /* Don't free used events. */ + set_bit(metric_events[i]->idx, evlist_used); + /* + * The metric leader points to the identically named event in + * metric_events. + */ + metric_events[i]->metric_leader = metric_events[i]; + /* + * Mark two events with identical names in the same group (or + * globally) as being in use as uncore events may be duplicated + * for each pmu. Set the metric leader to be the event that + * appears in metric_events. + */ + if (!has_constraint) { + for_each_group_evsel(ev, metric_events[i]->leader) { + if (ev != metric_events[i] && + !strcmp(metric_events[i]->name, ev->name)) { + set_bit(ev->idx, evlist_used); + ev->metric_leader = metric_events[i]; + } + } + } else { + evlist__for_each_entry(perf_evlist, ev) { + if (ev != metric_events[i] && + !strcmp(metric_events[i]->name, ev->name)) { + set_bit(ev->idx, evlist_used); + ev->metric_leader = metric_events[i]; + } + } + } } return metric_events[0]; -- 2.28.0.526.ge36021eeef-goog