As described in OpenCSD (CoreSight decoder lib), in the decoding stream it includes one trace element with type OCSD_GEN_TRC_ELEM_NO_SYNC; the element indicates 'either at start of decode, or after overflow / bad packet', we should take it as a signal for the tracing off and this will cause tracing discontinuity. From the trace dump with 'perf script', sometimes the element OCSD_GEN_TRC_ELEM_NO_SYNC collaborates with element OCSD_GEN_TRC_ELEM_TRACE_ON to show the tracing flow have been turned off and on, in this case the cs-etm code has handled TRACE_ON packet well so we observe the tracing discontinuity; but in another case it only inserts the element OCSD_GEN_TRC_ELEM_NO_SYNC into instructions packets, we miss to handle the case if has only standalone NO_SYNC element and users cannot receive the info for tracing discontinuity.
This patch introduces new type CS_ETM_TRACE_OFF to generate packet for receiving element OCSD_GEN_TRC_ELEM_NO_SYNC from decoder; when generate sample, CS_ETM_TRACE_OFF packet has almost the same behaviour with CS_ETM_TRACE_ON packet: both of them invokes cs_etm__flush() to generate samples for the previous instructions packet, and in cs_etm__sample() it also needs to generate samples if TRACE_OFF packet is followed by one sequential instructions packet. This patch also converts the address to 0 for TRACE_OFF packet, this is same with TRACE_ON packet as well.
Signed-off-by: Leo Yan leo.yan@linaro.org --- tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 10 ++++++++++ tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 7 ++++--- tools/perf/util/cs-etm.c | 15 +++++++++++---- 3 files changed, 25 insertions(+), 7 deletions(-)
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 5efb616..9d52727 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c @@ -369,6 +369,14 @@ cs_etm_decoder__buffer_range(struct cs_etm_decoder *decoder, }
static ocsd_datapath_resp_t +cs_etm_decoder__buffer_trace_off(struct cs_etm_decoder *decoder, + const uint8_t trace_chan_id) +{ + return cs_etm_decoder__buffer_packet(decoder, trace_chan_id, + CS_ETM_TRACE_OFF); +} + +static ocsd_datapath_resp_t cs_etm_decoder__buffer_trace_on(struct cs_etm_decoder *decoder, const uint8_t trace_chan_id) { @@ -389,6 +397,8 @@ 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: + resp = cs_etm_decoder__buffer_trace_off(decoder, + trace_chan_id); decoder->trace_on = false; break; case OCSD_GEN_TRC_ELEM_TRACE_ON: diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h index 9351bd1..a38c97c 100644 --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h @@ -23,9 +23,10 @@ struct cs_etm_buffer { };
enum cs_etm_sample_type { - CS_ETM_EMPTY = 0, - CS_ETM_RANGE = 1 << 0, - CS_ETM_TRACE_ON = 1 << 1, + CS_ETM_EMPTY = 0, + CS_ETM_RANGE = 1 << 0, + CS_ETM_TRACE_ON = 1 << 1, + CS_ETM_TRACE_OFF = 1 << 2, };
enum cs_etm_isa { diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index f4fa877..2a0cef9 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -517,8 +517,9 @@ static inline int cs_etm__t32_instr_size(struct cs_etm_queue *etmq,
static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet *packet) { - /* Returns 0 for the CS_ETM_TRACE_ON packet */ - if (packet->sample_type == CS_ETM_TRACE_ON) + /* Returns 0 for TRACE_ON and TRACE_OFF packets */ + if (packet->sample_type == CS_ETM_TRACE_ON || + packet->sample_type == CS_ETM_TRACE_OFF) return 0;
return packet->start_addr; @@ -527,8 +528,9 @@ static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet *packet) static inline u64 cs_etm__last_executed_instr(const struct cs_etm_packet *packet) { - /* Returns 0 for the CS_ETM_TRACE_ON packet */ - if (packet->sample_type == CS_ETM_TRACE_ON) + /* Returns 0 for TRACE_ON and TRACE_OFF packets */ + if (packet->sample_type == CS_ETM_TRACE_ON || + packet->sample_type == CS_ETM_TRACE_OFF) return 0;
return packet->end_addr - packet->last_instr_size; @@ -930,6 +932,10 @@ static int cs_etm__sample(struct cs_etm_queue *etmq) if (etmq->prev_packet->sample_type == CS_ETM_TRACE_ON) generate_sample = true;
+ /* Generate sample for tracing off packet */ + if (etmq->prev_packet->sample_type == CS_ETM_TRACE_OFF) + generate_sample = true; + /* Generate sample for branch taken packet */ if (etmq->prev_packet->sample_type == CS_ETM_RANGE && etmq->prev_packet->last_instr_taken_branch) @@ -1085,6 +1091,7 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq) cs_etm__sample(etmq); break; case CS_ETM_TRACE_ON: + case CS_ETM_TRACE_OFF: /* * Discontinuity in trace, flush * previous branch stack