CoreSight tracer driver might insert barrier packet between different buffers, thus the decoder can spot the boundaries based on the barrier packet; the decoder is possible to hit a barrier packet and emit a NO_SYNC element, then the decoder will find a periodic synchronisation point inside that next trace block that starts trace again but does not have the TRACE_ON element as indicator - usually because this block of trace has wrapped the buffer so we have lost the original point that trace was enabled.
In upper case, it results in the trace stream only inserts the OCSD_GEN_TRC_ELEM_NO_SYNC element in the middle of tracing stream, but we don't handle NO_SYNC element properly and at the end users miss to see the info for trace discontinuity.
Though OCSD_GEN_TRC_ELEM_NO_SYNC is different from CS_ETM_TRACE_ON when output from the decoder, but both of them indicate the trace data is discontinuous; this patch treats OCSD_GEN_TRC_ELEM_NO_SYNC as trace discontinuity and generates CS_ETM_DISCONTINUITY packet for it, so cs-etm can handle discontinuity for this case, finally it saves the last trace data for previous trace block and restart samples for new block.
Signed-off-by: Leo Yan leo.yan@linaro.org Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org Cc: Mike Leach mike.leach@linaro.org Cc: Robert Walker robert.walker@arm.com --- tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c index 1039f364..bee026e 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c @@ -410,7 +410,6 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer( case OCSD_GEN_TRC_ELEM_UNKNOWN: break; case OCSD_GEN_TRC_ELEM_NO_SYNC: - break; case OCSD_GEN_TRC_ELEM_TRACE_ON: resp = cs_etm_decoder__buffer_discontinuity(decoder, trace_chan_id);