perf tools: Allow out of order messages in forced flush

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.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-8q8794a8nlmpd1u8xrqmcyd2@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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",

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);

tools/perf/util/session.c

@@ -14,6 +14,7 @@
 #include "util.h"
 #include "cpumap.h"
 #include "perf_regs.h"
+#include "asm/bug.h"
 
 static int perf_session__open(struct perf_session *session)
 {
@@ -500,10 +501,15 @@ 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);