linux-kernel - [PATCH 1/2] perf intel-pt: Fix estimated timestamps for cycle-accurate mode

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Date:   Wed, 28 Sep 2016 14:41:35 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] perf intel-pt: Fix estimated timestamps for cycle-accurate mode

In cycle-accurate mode, timestamps can be calculated from CYC packets. The
decoder also estimates timestamps based on the number of instructions since
the last timestamp. For that to work in cycle-accurate mode, the
instruction count needs to be reset to zero when a timestamp is calculated
from a CYC packet, but that wasn't happening, so fix it.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Cc: stable@...r.kernel.org # v4.3+
---
 tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
index 7591a0c37473..3d1d446f037f 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -1353,6 +1353,8 @@ static void intel_pt_calc_cyc_timestamp(struct intel_pt_decoder *decoder)
 			     timestamp, decoder->timestamp);
 	else
 		decoder->timestamp = timestamp;
+
+	decoder->timestamp_insn_cnt = 0;
 }
 
 /* Walk PSB+ packets when already in sync. */
-- 
1.9.1