perf script: Add --show-round-event to display PERF_RECORD_FINISHED_ROUND

Adding --show-round-event to display PERF_RECORD_FINISHED_ROUND events
like:

  # perf script --show-round-events 2>/dev/null
               yes  8591 [002] 124177.397597:         18         cpu/mem-stores/P: ff...
               yes  8591 [002] 124177.397615:          1 cpu/mem-loads,ldlat=30/P: ff...
  PERF_RECORD_FINISHED_ROUND
              perf 10380 [001] 124177.397622:          6 cpu/mem-loads,ldlat=30/P: ff...
  PERF_RECORD_FINISHED_ROUND
           swapper     0 [000] 124177.400518:         88         cpu/mem-stores/P: ff...
           swapper     0 [000] 124177.400521:         88         cpu/mem-stores/P: ff...

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180206181813.10943-4-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-script.txt

@@ -303,6 +303,9 @@ OPTIONS
 --show-lost-events
 	Display lost events i.e. events of type PERF_RECORD_LOST.
 
+--show-round-events
+	Display finished round events i.e. events of type PERF_RECORD_FINISHED_ROUND.
+
 --demangle::
 	Demangle symbol names to human readable form. It's enabled by default,
 	disable with --no-demangle.

tools/perf/builtin-script.c

@@ -1489,6 +1489,7 @@ struct perf_script {
 	bool			show_switch_events;
 	bool			show_namespace_events;
 	bool			show_lost_events;
+	bool			show_round_events;
 	bool			allocated;
 	bool			per_event_dump;
 	struct cpu_map		*cpus;
@@ -2104,6 +2105,16 @@ process_lost_event(struct perf_tool *tool,
 	return 0;
 }
 
+static int
+process_finished_round_event(struct perf_tool *tool __maybe_unused,
+			     union perf_event *event,
+			     struct ordered_events *oe __maybe_unused)
+
+{
+	perf_event__fprintf(event, stdout);
+	return 0;
+}
+
 static void sig_handler(int sig __maybe_unused)
 {
 	session_done = 1;
@@ -2200,6 +2211,10 @@ static int __cmd_script(struct perf_script *script)
 		script->tool.namespaces = process_namespaces_event;
 	if (script->show_lost_events)
 		script->tool.lost = process_lost_event;
+	if (script->show_round_events) {
+		script->tool.ordered_events = false;
+		script->tool.finished_round = process_finished_round_event;
+	}
 
 	if (perf_script__setup_per_event_dump(script)) {
 		pr_err("Couldn't create the per event dump files\n");
@@ -3139,6 +3154,8 @@ int cmd_script(int argc, const char **argv)
 		    "Show namespace events (if recorded)"),
 	OPT_BOOLEAN('\0', "show-lost-events", &script.show_lost_events,
 		    "Show lost events (if recorded)"),
+	OPT_BOOLEAN('\0', "show-round-events", &script.show_round_events,
+		    "Show round events (if recorded)"),
 	OPT_BOOLEAN('\0', "per-event-dump", &script.per_event_dump,
 		    "Dump trace output to files named by the monitored events"),
 	OPT_BOOLEAN('f', "force", &symbol_conf.force, "don't complain, do it"),