[PATCH 19/19] perf tools: Allow out of order messages in forced flush

From: Jiri Olsa
Date: Fri Jul 25 2014 - 10:57:46 EST


In forced flush (OE_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 plus 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 | 12 +++++++++---
3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/ordered-events.c b/tools/perf/util/ordered-events.c
index 292cb627e51a..a62c6a8cd24d 100644
--- a/tools/perf/util/ordered-events.c
+++ b/tools/perf/util/ordered-events.c
@@ -169,6 +169,7 @@ int ordered_events_flush(struct perf_session *s, struct perf_tool *tool,
{
struct ordered_events *oe = &s->ordered_events;
static const char * const str[] = {
+ "NONE",
"FINAL",
"ROUND",
"HALF ",
@@ -198,6 +199,7 @@ int ordered_events_flush(struct perf_session *s, struct perf_tool *tool,
}

case OE_FLUSH__ROUND:
+ case OE_FLUSH__NONE:
default:
break;
};
@@ -211,6 +213,8 @@ int ordered_events_flush(struct perf_session *s, struct perf_tool *tool,
if (!err) {
if (how == OE_FLUSH__ROUND)
oe->next_flush = oe->max_timestamp;
+
+ oe->last_flush_type = how;
}

pr_oe_time(oe->next_flush, "next_flush - ordered_events_flush POST %s, nr_events %u\n",
diff --git a/tools/perf/util/ordered-events.h b/tools/perf/util/ordered-events.h
index a4fc435f0fc6..6dd36dd01be6 100644
--- a/tools/perf/util/ordered-events.h
+++ b/tools/perf/util/ordered-events.h
@@ -14,6 +14,7 @@ struct ordered_event {
};

enum oe_flush {
+ OE_FLUSH__NONE,
OE_FLUSH__FINAL,
OE_FLUSH__ROUND,
OE_FLUSH__HALF,
@@ -32,6 +33,7 @@ struct ordered_events {
struct ordered_event *last;
int buffer_idx;
unsigned int nr_events;
+ enum oe_flush last_flush_type;
};

struct ordered_event *ordered_events_new(struct ordered_events *oe, u64 timestamp);
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index fe868abd6c87..02dd6c65d8b8 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)
{
@@ -502,10 +503,15 @@ int perf_session_queue_event(struct perf_session *s, union perf_event *event,
return -ETIME;

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

new = ordered_events_new(oe, timestamp);
--
1.8.3.1

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