From: Adrian Hunter adrian.hunter@intel.com
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
--- tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c +++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c @@ -1313,8 +1313,11 @@ static int intel_pt_walk_tnt(struct inte 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; }