Messages in this thread | | | Date | Thu, 13 Dec 2018 09:38:54 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v3 6/8] perf cs-etm: Treat NO_SYNC element as trace discontinuity |
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Em Tue, Dec 11, 2018 at 03:38:26PM +0800, Leo Yan escreveu: > 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.
"In upper case"? Maybe:
In the former case it causes the insertion of a OCSD_GEN_TRC_ELEM_NO_SYNC in the middle of the the tracing stream, but as we were npt handling the NO_SYNC element properly which ends up making users miss the discontinuity indication"?
> 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
can we remove the "but" and "of them" (redundant) above?
> discontinuous; this patch treats OCSD_GEN_TRC_ELEM_NO_SYNC as trace a > discontinuity and generates CS_ETM_DISCONTINUITY packet for it, so > cs-etm can handle discontinuity for this case, finally it saves the last it (way too many "discontinuity") > 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); > -- > 2.7.4
--
- Arnaldo
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