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perf cs-etm: Fix start tracing packet handling 

Usually the start tracing packet is a CS_ETM_TRACE_ON packet, this
packet is passed to cs_etm__flush();  cs_etm__flush() will check the
condition 'prev_packet->sample_type == CS_ETM_RANGE' but 'prev_packet'
is allocated by zalloc() so 'prev_packet->sample_type' is zero in
initialization and this condition is false.  So cs_etm__flush() will
directly bail out without handling the start tracing packet.

This patch is to introduce a new sample type CS_ETM_EMPTY, which is used
to indicate the packet is an empty packet.  cs_etm__flush() will swap
packets when it finds the previous packet is empty, so this can record
the start tracing packet into 'etmq->prev_packet'.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1531295145-596-4-git-send-email-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Leo Yan 2018-07-11 15:45:42 +08:00 committed by Arnaldo Carvalho de Melo
parent 83868bf71d
commit 3eb3e07bcf
2 changed files with 19 additions and 1 deletions
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1
tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
View File

@ -23,6 +23,7 @@ struct cs_etm_buffer {
};
enum cs_etm_sample_type {
CS_ETM_EMPTY = 0,
CS_ETM_RANGE = 1 << 0,
CS_ETM_TRACE_ON = 1 << 1,
};

19
tools/perf/util/cs-etm.c
View File

@ -924,8 +924,14 @@ static int cs_etm__flush(struct cs_etm_queue *etmq)
int err = 0;
struct cs_etm_packet *tmp;
if (!etmq->prev_packet)
return 0;
/* Handle start tracing packet */
if (etmq->prev_packet->sample_type == CS_ETM_EMPTY)
goto swap_packet;
if (etmq->etm->synth_opts.last_branch &&
etmq->prev_packet &&
etmq->prev_packet->sample_type == CS_ETM_RANGE) {
/*
* Generate a last branch event for the branches left in the
@ -944,6 +950,10 @@ static int cs_etm__flush(struct cs_etm_queue *etmq)
etmq->period_instructions = 0;
}
swap_packet:
if (etmq->etm->synth_opts.last_branch) {
/*
* Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
* the next incoming packet.
@ -1023,6 +1033,13 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq)
*/
cs_etm__flush(etmq);
break;
case CS_ETM_EMPTY:
/*
* Should not receive empty packet,
* report error.
*/
pr_err("CS ETM Trace: empty packet\n");
return -EINVAL;
default:
break;
}