perf cs-etm: Optimize copying last branches

If an instruction range packet can generate multiple instruction
samples, these samples share the same last branches; it's not necessary
to copy the same last branches repeatedly for these samples within the
same packet.

This patch moves out the last branches copying from function
cs_etm__synth_instruction_sample(), and execute it prior to generating
instruction samples.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: coresight ml <coresight@lists.linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lore.kernel.org/lkml/20200219021811.20067-5-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 1ddcc67..87d9943 100644 (file)
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -1151,10 +1151,8 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,
 
        cs_etm__copy_insn(etmq, tidq->trace_chan_id, tidq->packet, &sample);
 
-       if (etm->synth_opts.last_branch) {
-               cs_etm__copy_last_branch_rb(etmq, tidq);
+       if (etm->synth_opts.last_branch)
                sample.branch_stack = tidq->last_branch;
-       }
 
        if (etm->synth_opts.inject) {
                ret = cs_etm__inject_event(event, &sample,
@@ -1431,6 +1429,10 @@ static int cs_etm__sample(struct cs_etm_queue *etmq,
                u64 offset = etm->instructions_sample_period - instrs_prev;
                u64 addr;
 
+               /* Prepare last branches for instruction sample */
+               if (etm->synth_opts.last_branch)
+                       cs_etm__copy_last_branch_rb(etmq, tidq);
+
                while (tidq->period_instructions >=
                                etm->instructions_sample_period) {
                        /*
@@ -1508,6 +1510,11 @@ static int cs_etm__flush(struct cs_etm_queue *etmq,
 
        if (etmq->etm->synth_opts.last_branch &&
            tidq->prev_packet->sample_type == CS_ETM_RANGE) {
+               u64 addr;
+
+               /* Prepare last branches for instruction sample */
+               cs_etm__copy_last_branch_rb(etmq, tidq);
+
                /*
                 * Generate a last branch event for the branches left in the
                 * circular buffer at the end of the trace.
@@ -1515,7 +1522,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq,
                 * Use the address of the end of the last reported execution
                 * range
                 */
-               u64 addr = cs_etm__last_executed_instr(tidq->prev_packet);
+               addr = cs_etm__last_executed_instr(tidq->prev_packet);
 
                err = cs_etm__synth_instruction_sample(
                        etmq, tidq, addr,
@@ -1560,11 +1567,16 @@ static int cs_etm__end_block(struct cs_etm_queue *etmq,
         */
        if (etmq->etm->synth_opts.last_branch &&
            tidq->prev_packet->sample_type == CS_ETM_RANGE) {
+               u64 addr;
+
+               /* Prepare last branches for instruction sample */
+               cs_etm__copy_last_branch_rb(etmq, tidq);
+
                /*
                 * Use the address of the end of the last reported execution
                 * range.
                 */
-               u64 addr = cs_etm__last_executed_instr(tidq->prev_packet);
+               addr = cs_etm__last_executed_instr(tidq->prev_packet);
 
                err = cs_etm__synth_instruction_sample(
                        etmq, tidq, addr,