perf stat: Separate bperf from bpf_profiler

It seems that perf stat -b <prog id> doesn't produce any results:

    $ perf stat -e cycles -b 4 -I 10000 -vvv
    Control descriptor is not initialized
    cycles: 0 0 0
                time        counts unit      events
	10.007641640    <not supported>      cycles

Looks like this happens because fentry/fexit progs are getting loaded, but the
corresponding perf event is not enabled and not added into the events bpf map.
I think there is some mixing up between two type of bpf support, one for bperf
and one for bpf_profiler. Both are identified via evsel__is_bpf, based on which
perf events are enabled, but for the latter (bpf_profiler) a perf event is
required. Using evsel__is_bperf to check only bperf produces expected results:

    $ perf stat -e cycles -b 4 -I 10000 -vvv
    Control descriptor is not initialized
    ------------------------------------------------------------
    perf_event_attr:
      size                             136
      sample_type                      IDENTIFIER
      read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
      disabled                         1
      exclude_guest                    1
    ------------------------------------------------------------
    sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 3
    ------------------------------------------------------------
    [...perf_event_attr for other CPUs...]
    ------------------------------------------------------------
    cycles: 309426 169009 169009
		time             counts unit events
	10.010091271             309426      cycles

The final numbers correspond (at least in the level of magnitude) to the
same metric obtained via bpftool.

Fixes: 112cb56 ("perf stat: Introduce config stat.bpf-counter-events")
Reviewed-by: Song Liu <[email protected]>
Signed-off-by: Dmitrii Dolgov <[email protected]>
Tested-by: Song Liu <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Song Liu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: erthalion

tools/perf/builtin-stat.c

@@ -712,7 +712,7 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
 		counter->reset_group = false;
 		if (bpf_counter__load(counter, &target))
 			return -1;
-		if (!evsel__is_bpf(counter))
+		if (!(evsel__is_bperf(counter)))
 			all_counters_use_bpf = false;
 	}
 
@@ -728,7 +728,7 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
 
 		if (counter->reset_group || counter->errored)
 			continue;
-		if (evsel__is_bpf(counter))
+		if (evsel__is_bperf(counter))
 			continue;
 try_again:
 		if (create_perf_stat_counter(counter, &stat_config, &target,

tools/perf/util/evsel.h

@@ -269,6 +269,11 @@ static inline bool evsel__is_bpf(struct evsel *evsel)
 	return evsel->bpf_counter_ops != NULL;
 }
 
+static inline bool evsel__is_bperf(struct evsel *evsel)
+{
+	return evsel->bpf_counter_ops != NULL && list_empty(&evsel->bpf_counter_list);
+}
+
 #define EVSEL__MAX_ALIASES 8
 
 extern const char *const evsel__hw_cache[PERF_COUNT_HW_CACHE_MAX][EVSEL__MAX_ALIASES];