The existing method to synthesize instruction samples has the following issues: 1. Branch instruction mnemonics were being added to non-branch instructions too. 2. Branch target address was missing
To fix the issues, start synthesizing the instructions from the previous packet (tidq->prev_packet) instead of current packet (tidq->packet). This way it's easy to figure out the target address of the branch instruction in tidq->prev_packet which is the current packet's (tidq->packet) first executed instruction.
Since we have now switched to processing the previous packet first, we need not swap the packets during cs_etm__flush().
Signed-off-by: Tanmay Jagdale tanmay@marvell.com Reviewed-by: James Clark james.clark@arm.com --- tools/perf/util/cs-etm.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-)
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 0bf9e5c27b59..ebed5b98860e 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -1576,10 +1576,26 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq, sample.stream_id = etmq->etm->instructions_id; sample.period = period; sample.cpu = tidq->packet->cpu; - sample.flags = tidq->prev_packet->flags; sample.cpumode = event->sample.header.misc;
- cs_etm__copy_insn(etmq, tidq->trace_chan_id, tidq->packet, &sample); + cs_etm__copy_insn(etmq, tidq->trace_chan_id, tidq->prev_packet, &sample); + + /* Populate branch target information only when we encounter + * branch instruction, which is at the end of tidq->prev_packet. + */ + if (addr == (tidq->prev_packet->end_addr - 4)) { + /* Update the perf_sample flags using the prev_packet + * since that is the queue we are synthesizing. + */ + sample.flags = tidq->prev_packet->flags; + + /* The last instruction of the previous queue would be a + * branch operation. Get the target of that branch by looking + * into the first executed instruction of the current packet + * queue. + */ + sample.addr = cs_etm__first_executed_instr(tidq->packet); + }
if (etm->synth_opts.last_branch) sample.branch_stack = tidq->last_branch; @@ -1771,7 +1787,7 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, /* Get instructions remainder from previous packet */ instrs_prev = tidq->period_instructions;
- tidq->period_instructions += tidq->packet->instr_count; + tidq->period_instructions += tidq->prev_packet->instr_count;
/* * Record a branch when the last instruction in @@ -1851,8 +1867,11 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, * been executed, but PC has not advanced to next * instruction) */ + /* Get address from prev_packet since we are synthesizing + * that in cs_etm__synth_instruction_sample() + */ addr = cs_etm__instr_addr(etmq, trace_chan_id, - tidq->packet, offset - 1); + tidq->prev_packet, offset - 1); ret = cs_etm__synth_instruction_sample( etmq, tidq, addr, etm->instructions_sample_period); @@ -1916,7 +1935,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq,
/* Handle start tracing packet */ if (tidq->prev_packet->sample_type == CS_ETM_EMPTY) - goto swap_packet; + goto reset_last_br;
if (etmq->etm->synth_opts.last_branch && etmq->etm->synth_opts.instructions && @@ -1952,8 +1971,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq, return err; }
-swap_packet: - cs_etm__packet_swap(etm, tidq); +reset_last_br:
/* Reset last branches after flush the trace */ if (etm->synth_opts.last_branch)