Jin Yao reported the issue (and posted first versions of this change)
with groups being defined over events with different cpu mask.
This causes assert aborts in get_group_fd, like:
# perf stat -M "C2_Pkg_Residency" -a -- sleep 1
perf: util/evsel.c:1464: get_group_fd: Assertion `!(fd == -1)' failed.
Aborted
All the events in the group have to be defined over the same cpus so the
group_fd can be found for every leader/member pair.
Adding check to ensure this condition is met and removing the group
(with warning) if we detect mixed cpus, like:
$ sudo perf stat -e '{power/energy-cores/,cycles},{instructions,power/energy-cores/}'
WARNING: event cpu maps do not match, disabling group:
anon group { power/energy-cores/, cycles }
anon group { instructions, power/energy-cores/ }
Ian asked also for cpu maps details, it's displayed in verbose mode:
$ sudo perf stat -e '{cycles,power/energy-cores/}' -v
WARNING: group events cpu maps do not match, disabling group:
anon group { power/energy-cores/, cycles }
power/energy-cores/: 0
cycles: 0-7
anon group { instructions, power/energy-cores/ }
instructions: 0-7
power/energy-cores/: 0
Committer testing:
[root@seventh ~]# perf stat -e '{power/energy-cores/,cycles},{instructions,power/energy-cores/}'
WARNING: grouped events cpus do not match, disabling group:
anon group { power/energy-cores/, cycles }
anon group { instructions, power/energy-cores/ }
^C
Performance counter stats for 'system wide':
12.62 Joules power/energy-cores/
106,920,637 cycles
80,228,899 instructions # 0.75 insn per cycle
12.62 Joules power/energy-cores/
14.
514476987 seconds time elapsed
[root@seventh ~]#
But if we put compatible events in each group it works:
[root@seventh ~]# perf stat -e '{power/energy-cores/,power/energy-ram/},{instructions,cycles}' -a sleep 2
Performance counter stats for 'system wide':
1.95 Joules power/energy-cores/
0.92 Joules power/energy-ram/
29,305,715 instructions # 1.03 insn per cycle
28,423,338 cycles
2.
001438142 seconds time elapsed
[root@seventh ~]#
This needs improvement tho:
[root@seventh ~]# perf stat -e '{power/energy-cores/,power/energy-ram/},{instructions,cycles}' sleep 2
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (power/energy-cores/).
/bin/dmesg | grep -i perf may provide additional information.
[root@seventh ~]#
We need to emit a better message, one stating that the power/ events
can't be used for a specific workload, instead it is per-cpu or system
wide.
Fixes: 6a4bb04caacc8 ("perf tools: Enable grouping logic for parsed events")
Co-developed-by: Jin Yao <yao.jin@linux.intel.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200602101736.GE1112120@krava
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
.big_num = true,
};
+static bool cpus_map_matched(struct evsel *a, struct evsel *b)
+{
+ if (!a->core.cpus && !b->core.cpus)
+ return true;
+
+ if (!a->core.cpus || !b->core.cpus)
+ return false;
+
+ if (a->core.cpus->nr != b->core.cpus->nr)
+ return false;
+
+ for (int i = 0; i < a->core.cpus->nr; i++) {
+ if (a->core.cpus->map[i] != b->core.cpus->map[i])
+ return false;
+ }
+
+ return true;
+}
+
+static void evlist__check_cpu_maps(struct evlist *evlist)
+{
+ struct evsel *evsel, *pos, *leader;
+ char buf[1024];
+
+ evlist__for_each_entry(evlist, evsel) {
+ leader = evsel->leader;
+
+ /* Check that leader matches cpus with each member. */
+ if (leader == evsel)
+ continue;
+ if (cpus_map_matched(leader, evsel))
+ continue;
+
+ /* If there's mismatch disable the group and warn user. */
+ WARN_ONCE(1, "WARNING: grouped events cpus do not match, disabling group:\n");
+ evsel__group_desc(leader, buf, sizeof(buf));
+ pr_warning(" %s\n", buf);
+
+ if (verbose) {
+ cpu_map__snprint(leader->core.cpus, buf, sizeof(buf));
+ pr_warning(" %s: %s\n", leader->name, buf);
+ cpu_map__snprint(evsel->core.cpus, buf, sizeof(buf));
+ pr_warning(" %s: %s\n", evsel->name, buf);
+ }
+
+ for_each_group_evsel(pos, leader) {
+ pos->leader = pos;
+ pos->core.nr_members = 0;
+ }
+ evsel->leader->core.nr_members = 0;
+ }
+}
+
static inline void diff_timespec(struct timespec *r, struct timespec *a,
struct timespec *b)
{
goto out;
}
+ evlist__check_cpu_maps(evsel_list);
+
/*
* Initialize thread_map with comm names,
* so we could print it out on output.