From: Ian Rogers irogers@google.com
[ Upstream commit dcc81be0fc4e66943041e6e19a5faf8f8704a27e ]
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
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.jin@linux.intel.com Signed-off-by: Ian Rogers irogers@google.com Cc: Adrian Hunter adrian.hunter@intel.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Alexei Starovoitov ast@kernel.org Cc: Andi Kleen ak@linux.intel.com Cc: Andrii Nakryiko andriin@fb.com Cc: Athira Jajeev atrajeev@linux.vnet.ibm.com Cc: Daniel Borkmann daniel@iogearbox.net Cc: Jiri Olsa jolsa@redhat.com Cc: John Fastabend john.fastabend@gmail.com Cc: KP Singh kpsingh@chromium.org Cc: Mark Rutland mark.rutland@arm.com Cc: Martin KaFai Lau kafai@fb.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Song Liu songliubraving@fb.com Cc: Stephane Eranian eranian@google.com Cc: Yonghong Song yhs@fb.com Cc: bpf@vger.kernel.org Cc: netdev@vger.kernel.org Link: http://lore.kernel.org/lkml/20200917201807.4090224-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/metricgroup.c | 75 ++++++++++++++++++++++++++--------- 1 file changed, 56 insertions(+), 19 deletions(-)
diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c index ab5030fcfed4e..d948a7f910cfa 100644 --- a/tools/perf/util/metricgroup.c +++ b/tools/perf/util/metricgroup.c @@ -150,6 +150,18 @@ static void expr_ids__exit(struct expr_ids *ids) free(ids->id[i].id); }
+static bool contains_event(struct evsel **metric_events, int num_events, + const char *event_name) +{ + int i; + + for (i = 0; i < num_events; i++) { + if (!strcmp(metric_events[i]->name, event_name)) + return true; + } + return false; +} + /** * Find a group of events in perf_evlist that correpond to those from a parsed * metric expression. Note, as find_evsel_group is called in the same order as @@ -180,7 +192,11 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist, int i = 0, matched_events = 0, events_to_match; const int idnum = (int)hashmap__size(&pctx->ids);
- /* duration_time is grouped separately. */ + /* + * duration_time is always grouped separately, when events are grouped + * (ie has_constraint is false) then ignore it in the matching loop and + * add it to metric_events at the end. + */ if (!has_constraint && hashmap__find(&pctx->ids, "duration_time", (void **)&val_ptr)) events_to_match = idnum - 1; @@ -207,23 +223,20 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist, sizeof(struct evsel *) * idnum); current_leader = ev->leader; } - if (hashmap__find(&pctx->ids, ev->name, (void **)&val_ptr)) { - if (has_constraint) { - /* - * Events aren't grouped, ensure the same event - * isn't matched from two groups. - */ - for (i = 0; i < matched_events; i++) { - if (!strcmp(ev->name, - metric_events[i]->name)) { - break; - } - } - if (i != matched_events) - continue; - } + /* + * 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. If events aren't grouped then this also + * ensures that the same event in different sibling groups + * aren't both added to metric_events. + */ + if (contains_event(metric_events, matched_events, ev->name)) + continue; + /* Does this event belong to the parse context? */ + if (hashmap__find(&pctx->ids, ev->name, (void **)&val_ptr)) metric_events[matched_events++] = ev; - } + if (matched_events == events_to_match) break; } @@ -239,7 +252,7 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist, }
if (matched_events != idnum) { - /* Not whole match */ + /* Not a whole match */ return NULL; }
@@ -247,8 +260,32 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist,
for (i = 0; i < idnum; i++) { ev = metric_events[i]; - ev->metric_leader = ev; + /* Don't free the used events. */ set_bit(ev->idx, evlist_used); + /* + * The metric leader points to the identically named event in + * metric_events. + */ + ev->metric_leader = ev; + /* + * 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 of such events to be the + * event that appears in metric_events. + */ + evlist__for_each_entry_continue(perf_evlist, ev) { + /* + * If events are grouped then the search can terminate + * when then group is left. + */ + if (!has_constraint && + ev->leader != metric_events[i]->leader) + break; + if (!strcmp(metric_events[i]->name, ev->name)) { + set_bit(ev->idx, evlist_used); + ev->metric_leader = metric_events[i]; + } + } }
return metric_events[0];