[PATCH 18/18] perf tools: Allow out of order messages in forced flush

From: Jiri Olsa
Date: Wed Jun 18 2014 - 11:00:15 EST


In forced flush (OEQ_FLUSH__HALF) we break the rules of the
flush timestamp via PERF_RECORD_FINISHED_ROUND event, so
we could get out of order event.

Do not force error in this case and also changing the
output warning to use WARN_ONCE.

Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jean Pihet <jean.pihet@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
tools/perf/util/ordered-events.c | 4 ++++
tools/perf/util/ordered-events.h | 2 ++
tools/perf/util/session.c | 8 ++++++--
3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/ordered-events.c b/tools/perf/util/ordered-events.c
index aa98b6a..bfaf065 100644
--- a/tools/perf/util/ordered-events.c
+++ b/tools/perf/util/ordered-events.c
@@ -213,12 +213,14 @@ int ordered_events_flush(struct perf_session *s, struct perf_tool *tool,
}

case OEQ_FLUSH__ROUND:
+ case OEQ_FLUSH__NONE:
default:
break;
};

if (unlikely(debug_sample_queue)) {
static const char * const str[] = {
+ "NONE",
"FINAL",
"ROUND",
"HALF ",
@@ -235,6 +237,8 @@ int ordered_events_flush(struct perf_session *s, struct perf_tool *tool,
if (!err) {
if (how == OEQ_FLUSH__ROUND)
q->next_flush = q->max_timestamp;
+
+ q->last_flush_type = how;
}

if (unlikely(debug_sample_queue)) {
diff --git a/tools/perf/util/ordered-events.h b/tools/perf/util/ordered-events.h
index 8a717de..7e92688 100644
--- a/tools/perf/util/ordered-events.h
+++ b/tools/perf/util/ordered-events.h
@@ -14,6 +14,7 @@ struct ordered_event {
};

enum oeq_flush {
+ OEQ_FLUSH__NONE,
OEQ_FLUSH__FINAL,
OEQ_FLUSH__ROUND,
OEQ_FLUSH__HALF,
@@ -32,6 +33,7 @@ struct ordered_events_queue {
struct ordered_event *last;
int buffer_idx;
unsigned int nr_events;
+ enum oeq_flush last_flush_type;
};

struct ordered_event *ordered_events_get(struct ordered_events_queue *q,
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 28fe6a1..337a783 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -15,6 +15,7 @@
#include "cpumap.h"
#include "perf_regs.h"
#include "vdso.h"
+#include "asm/bug.h"

static int perf_session__open(struct perf_session *session)
{
@@ -502,8 +503,11 @@ int perf_session_queue_event(struct perf_session *s, union perf_event *event,
return -ETIME;

if (timestamp < s->ordered_events.last_flush) {
- printf("Warning: Timestamp below last timeslice flush\n");
- return -EINVAL;
+ WARN_ONCE(1, "Timestamp below last timeslice flush\n");
+
+ /* We could get out of order messages after forced flush. */
+ if (q->last_flush_type != OEQ_FLUSH__HALF)
+ return -EINVAL;
}

new = ordered_events_get(q, timestamp);
--
1.8.3.1

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