Commit 7c246504 authored May 10, 2019 by Adrian Hunter Committed by Greg Kroah-Hartman May 25, 2019

perf intel-pt: Fix sample timestamp wrt non-taken branches



commit 1b6599a9d8e6c9f7e9b0476012383b1777f7fc93 upstream.

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>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org # v4.4+
Fixes: 3f04d98e972b ("perf intel-pt: Improve sample timestamp")
Link: http://lkml.kernel.org/r/20190510124143.27054-4-adrian.hunter@intel.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 8a566f7c

tools/perf/util/intel-pt-decoder/intel-pt-decoder.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1235,8 +1235,11 @@ 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;
		}