linux-kernel - [tip:perf/urgent] perf intel-pt: Fix estimated timestamps for cycle-accurate mode

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Message-ID: <tip-51ee6481fa8e879cc942bcc1b0af713e158b7a98@git.kernel.org>
Date:   Thu, 6 Oct 2016 15:40:28 -0700
From:   tip-bot for Adrian Hunter <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, acme@...hat.com, mingo@...nel.org,
        hpa@...or.com, adrian.hunter@...el.com, jolsa@...hat.com,
        linux-kernel@...r.kernel.org
Subject: [tip:perf/urgent] perf intel-pt: Fix estimated timestamps for
 cycle-accurate mode

Commit-ID:  51ee6481fa8e879cc942bcc1b0af713e158b7a98
Gitweb:     http://git.kernel.org/tip/51ee6481fa8e879cc942bcc1b0af713e158b7a98
Author:     Adrian Hunter <adrian.hunter@...el.com>
AuthorDate: Wed, 28 Sep 2016 14:41:35 +0300
Committer:  Arnaldo Carvalho de Melo <acme@...hat.com>
CommitDate: Wed, 5 Oct 2016 08:15:29 -0300

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: Jiri Olsa <jolsa@...hat.com>
Cc: stable@...r.kernel.org # v4.3+
Link: http://lkml.kernel.org/r/1475062896-22274-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 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 7591a0c..3d1d446 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. */