[PATCH 1/2] perf: Introduce a new "round of buffers read" pseudo event

[Frederic Weisbecker <fweisbec@gmail.com>]

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

This patch introduces a new PERF_RECORD_FINISHED_ROUND pseudo event
that only consists 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>
---
 tools/perf/builtin-record.c |   34 ++++++++++++++++++++++++----------
 tools/perf/util/event.h     |    3 ++-
 2 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 0ff67d1..96bbf42 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -494,6 +494,29 @@ static void event__synthesize_guest_os(struct machine *machine, void *data)
 		       " relocation symbol.\n", machine->pid);
 }
 
+static struct perf_event_header finished_round_event = {
+	.size = sizeof(struct perf_event_header),
+	.type = PERF_RECORD_FINISHED_ROUND,
+};
+
+static void mmap_read_all(void)
+{
+	int i, counter, thread;
+
+	for (i = 0; i < nr_cpu; i++) {
+		for (counter = 0; counter < nr_counters; counter++) {
+			for (thread = 0; thread < thread_num; thread++) {
+				if (mmap_array[i][counter][thread].base)
+					mmap_read(&mmap_array[i][counter][thread]);
+			}
+
+		}
+	}
+
+	if (perf_header__has_feat(&session->header, HEADER_TRACE_INFO))
+		write_output(&finished_round_event, sizeof(finished_round_event));
+}
+
 static int __cmd_record(int argc, const char **argv)
 {
 	int i, counter;
@@ -735,16 +758,7 @@ static int __cmd_record(int argc, const char **argv)
 		int hits = samples;
 		int thread;
 
-		for (i = 0; i < nr_cpu; i++) {
-			for (counter = 0; counter < nr_counters; counter++) {
-				for (thread = 0;
-					thread < thread_num; thread++) {
-					if (mmap_array[i][counter][thread].base)
-						mmap_read(&mmap_array[i][counter][thread]);
-				}
-
-			}
-		}
+		mmap_read_all();
 
 		if (hits == samples) {
 			if (done)
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 @@ struct build_id_event {
 	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
 };
 
-- 
1.6.2.3