perf lock: Print the number of lost entries for BPF

Like the normal 'perf lock contention' output, it'd print the number of
lost entries for BPF if exists or -v option is passed.

Currently it uses BROKEN_CONTENDED stat for the lost count (due to full
stack maps).

  $ sudo perf lock con -a -b --map-nr-entries 128 sleep 5
  ...
  === output for debug===

  bad: 43, total: 14903
  bad rate: 0.29 %
  histogram of events caused bad sequence
      acquire: 0
     acquired: 0
    contended: 43
      release: 0

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220802191004.347740-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index c6cc6c296419..dd11d3471baf 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -1472,8 +1472,11 @@ static void print_contention_result(void)
 		pr_info("  %10s   %s\n\n", "type", "caller");
 
 	bad = total = 0;
+	if (use_bpf)
+		bad = bad_hist[BROKEN_CONTENDED];
+
 	while ((st = pop_from_result())) {
-		total++;
+		total += use_bpf ? st->nr_contended : 1;
 		if (st->broken)
 			bad++;
 
@@ -1687,6 +1690,9 @@ static int __cmd_contention(int argc, const char **argv)
 
 		lock_contention_stop();
 		lock_contention_read(&con);
+
+		/* abuse bad hist stats for lost entries */
+		bad_hist[BROKEN_CONTENDED] = con.lost;
 	} else {
 		err = perf_session__process_events(session);
 		if (err)