From: Adrian Hunter adrian.hunter@intel.com
timestamp_insn_cnt is used to estimate the timestamp based on the number of instructions since the last known timestamp.
If the estimate is not accurate enough decoding might not be correctly synchronized with side-band events causing more trace errors.
However there are always timestamps following an overflow, so the estimate is not needed and can indeed result in more errors.
Suppress the estimate by setting timestamp_insn_cnt to zero.
Signed-off-by: Adrian Hunter adrian.hunter@intel.com Cc: Jiri Olsa jolsa@redhat.com Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1520431349-30689-5-git-send-email-adrian.hunter@int... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com --- tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 1 + 1 file changed, 1 insertion(+)
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 5e4d0bbafc8b..f9157aed1289 100644 --- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c +++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c @@ -1378,6 +1378,7 @@ static int intel_pt_overflow(struct intel_pt_decoder *decoder) intel_pt_clear_tx_flags(decoder); decoder->have_tma = false; decoder->cbr = 0; + decoder->timestamp_insn_cnt = 0; decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC; decoder->overflow = true; return -EOVERFLOW;