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From: Adrian Hunter <adrian.hunter@intel.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>, linux-kernel@vger.kernel.org
Subject: [PATCH 3/3] perf intel-pt: Fix sample timestamp wrt non-taken branches
Date: Fri, 10 May 2019 15:41:43 +0300	[thread overview]
Message-ID: <20190510124143.27054-4-adrian.hunter@intel.com> (raw)
In-Reply-To: <20190510124143.27054-1-adrian.hunter@intel.com>

The sample timestamp is updated to ensure that the timestamp represents
the time of the sample and not a branch that the decoder is still
walking towards. The sample timestamp is updated when the decoder
returns, but the decoder does not return for non-taken branches. Update
the sample timestamp then also.

Note that commit 3f04d98e972b5 ("perf intel-pt: Improve sample timestamp")
was also a stable fix and appears, for example, in v4.4 stable tree as
commit a4ebb58fd124 ("perf intel-pt: Improve sample timestamp").

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: 3f04d98e972b ("perf intel-pt: Improve sample timestamp")
Cc: stable@vger.kernel.org # v4.4+
---
 tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

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 9cbd587489bf..f4c3c84b090f 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -1318,8 +1318,11 @@ static int intel_pt_walk_tnt(struct intel_pt_decoder *decoder)
 				return 0;
 			}
 			decoder->ip += intel_pt_insn.length;
-			if (!decoder->tnt.count)
+			if (!decoder->tnt.count) {
+				decoder->sample_timestamp = decoder->timestamp;
+				decoder->sample_insn_cnt = decoder->timestamp_insn_cnt;
 				return -EAGAIN;
+			}
 			decoder->tnt.payload <<= 1;
 			continue;
 		}
-- 
2.17.1


  parent reply	other threads:[~2019-05-10 12:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-10 12:41 [PATCH 0/3] perf intel-pt: Intel PT fixes Adrian Hunter
2019-05-10 12:41 ` [PATCH 1/3] perf intel-pt: Fix instructions sampling rate Adrian Hunter
2019-05-18  9:32   ` [tip:perf/core] " tip-bot for Adrian Hunter
2019-05-10 12:41 ` [PATCH 2/3] perf intel-pt: Fix improved sample timestamp Adrian Hunter
2019-05-18  9:33   ` [tip:perf/core] " tip-bot for Adrian Hunter
2019-05-10 12:41 ` Adrian Hunter [this message]
2019-05-18  9:34   ` [tip:perf/core] perf intel-pt: Fix sample timestamp wrt non-taken branches tip-bot for Adrian Hunter
2019-05-15 19:30 ` [PATCH 0/3] perf intel-pt: Intel PT fixes Arnaldo Carvalho de Melo

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