From: Frederic Weisbecker on
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(a)gmail.com>
Cc: Ingo Molnar <mingo(a)elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra(a)chello.nl>
Cc: Arnaldo Carvalho de Melo <acme(a)redhat.com>
Cc: Paul Mackerras <paulus(a)samba.org>
Cc: Tom Zanussi <tzanussi(a)gmail.com>
Cc: Masami Hiramatsu <mhiramat(a)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

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