linux-kernel - [PATCH] perf tools: Fix Intel BTS/PT timestamp handling

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Date:	Thu, 20 Aug 2015 11:51:32 +0300
From:	Adrian Hunter <adrian.hunter@...el.com>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:	linux-kernel@...r.kernel.org, Jiri Olsa <jolsa@...hat.com>
Subject: [PATCH] perf tools: Fix Intel BTS/PT timestamp handling

Events that don't sample the timestamp have a timestamp
value of -1.  Intel BTS and Intel PT processing wasn't
taking that into account.  This is particularly noticeable
with Intel BTS because timestamps are not requested by
default.  Then, if the conversion of -1 to TSC results
in a small number, the processing is unaffected.
However if the conversion results in a big number, then
the data is processed prematurely before relevant sideband
data like mmap events, which in turn results in samples
with unknown dsos.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
 tools/perf/util/intel-bts.c | 2 +-
 tools/perf/util/intel-pt.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/intel-bts.c b/tools/perf/util/intel-bts.c
index dce99cfb1309..ea768625ab5b 100644
--- a/tools/perf/util/intel-bts.c
+++ b/tools/perf/util/intel-bts.c
@@ -610,7 +610,7 @@ static int intel_bts_process_event(struct perf_session *session,
 		return -EINVAL;
 	}
 
-	if (sample->time)
+	if (sample->time && sample->time != (u64)-1)
 		timestamp = perf_time_to_tsc(sample->time, &bts->tc);
 	else
 		timestamp = 0;
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 2a4a4120473b..a5acd2fe2447 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -1450,7 +1450,7 @@ static int intel_pt_process_event(struct perf_session *session,
 		return -EINVAL;
 	}
 
-	if (sample->time)
+	if (sample->time && sample->time != (u64)-1)
 		timestamp = perf_time_to_tsc(sample->time, &pt->tc);
 	else
 		timestamp = 0;
-- 
1.9.1

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