perf lock: Allow concurrent record and report

To support live monitoring of kernel lock contention without BPF,
it should support something like below:

  # perf lock record -a -o- sleep 1 | perf lock contention -i-
   contended   total wait     max wait     avg wait         type   caller

           2     10.27 us      6.17 us      5.13 us     spinlock   load_balance+0xc03
           1      5.29 us      5.29 us      5.29 us     rwlock:W   ep_scan_ready_list+0x54
           1      4.12 us      4.12 us      4.12 us     spinlock   smpboot_thread_fn+0x116
           1      3.28 us      3.28 us      3.28 us        mutex   pipe_read+0x50

To do that, it needs to handle HEAD_ATTR, HEADER_EVENT_UPDATE and
HEADER_TRACING_DATA which are generated only for the pipe mode.
And setting event handler also should be delayed until it gets the
event information.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221104051440.220989-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/tools/perf/tests/shell/lock_contention.sh b/tools/perf/tests/shell/lock_contention.sh
index 04bf604e3c6f..f7bd0d8eb5c3 100755
--- a/tools/perf/tests/shell/lock_contention.sh
+++ b/tools/perf/tests/shell/lock_contention.sh
@@ -53,7 +53,7 @@ test_bpf()
 
 	if ! perf lock con -b true > /dev/null 2>&1 ; then
 		echo "[Skip] No BPF support"
-		exit
+		return
 	fi
 
 	# the perf lock contention output goes to the stderr
@@ -65,9 +65,22 @@ test_bpf()
 	fi
 }
 
+test_record_concurrent()
+{
+	echo "Testing perf lock record and perf lock contention at the same time"
+	perf lock record -o- -- perf bench sched messaging 2> /dev/null | \
+	perf lock contention -i- -E 1 -q 2> ${result}
+	if [ $(cat "${result}" | wc -l) != "1" ]; then
+		echo "[Fail] Recorded result count is not 1:" $(cat "${result}" | wc -l)
+		err=1
+		exit
+	fi
+}
+
 check
 
 test_record
 test_bpf
+test_record_concurrent
 
 exit ${err}