perf: Introduce a new "round of buffers read" pseudo event

In order to provide a more rubust and deterministic reordering
algorithm, we need to know when we reach a point where we just
did a pass through over every counter buffers to read every thing
they had.

This patch introduces a new PERF_RECORD_FINISHED_ROUND pseudo event
that only consist in an event header and doesn't need to contain
anything.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index b364da5..6cc1b1d 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -84,11 +84,12 @@
 	char			 filename[];
 };
 
-enum perf_header_event_type { /* above any possible kernel type */
+enum perf_user_event_type { /* above any possible kernel type */
 	PERF_RECORD_HEADER_ATTR			= 64,
 	PERF_RECORD_HEADER_EVENT_TYPE		= 65,
 	PERF_RECORD_HEADER_TRACING_DATA		= 66,
 	PERF_RECORD_HEADER_BUILD_ID		= 67,
+	PERF_RECORD_FINISHED_ROUND		= 68,
 	PERF_RECORD_HEADER_MAX
 };