Re: [PATCH v2 3/6] perf cs-etm: Rename CS_ETM_TRACE_ON to CS_ETM_DISCONTINUITY

Mathieu Poirier
2018-12-10T22:51:38Z

Hi Leo,

On Mon, Dec 10, 2018 at 04:52:58PM +0800, Leo Yan wrote:
> TRACE_ON element is used at the beginning of trace, it also can be
> appeared in the middle of trace data to indicate discontinuity; for
> example, it's possible to see multiple TRACE_ON elements in the trace
> stream if the trace is being limited by address range filtering.
>
> Furthermore, except TRACE_ON element is for discontinuity, NO_SYNC and
> EO_TRACE also can be used to indicate discontinuity, though they are
> used for different scenarios for trace is interrupted.
>
> This patch is to rename sample type CS_ETM_TRACE_ON to
> CS_ETM_DISCONTINUITY, firstly the new name describes more closely the
> purpose of the packet; secondly this is a preparation for other output
> elements which also cause the trace discontinuity thus they can share
> the same one packet type.
>
> This patch also refactors the enumerations in cs_etm_sample_type by
> converting from bit shifting value to continuous numbers.
>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Mike Leach <mike.leach@linaro.org>
> Cc: Robert Walker <robert.walker@arm.com>
> 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 | 6 +++---
> tools/perf/util/cs-etm.c | 12 ++++++------
> 3 files changed, 14 insertions(+), 14 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 0b4c862..a3994f1 100644
> --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> @@ -391,11 +391,11 @@ cs_etm_decoder__buffer_range(struct cs_etm_decoder *decoder,
> }
>
> static ocsd_datapath_resp_t
> -cs_etm_decoder__buffer_trace_on(struct cs_etm_decoder *decoder,
> - const uint8_t trace_chan_id)
> +cs_etm_decoder__buffer_discontinuity(struct cs_etm_decoder *decoder,
> + const uint8_t trace_chan_id)
> {
> return cs_etm_decoder__buffer_packet(decoder, trace_chan_id,
> - CS_ETM_TRACE_ON);
> + CS_ETM_DISCONTINUITY);
> }
>
> static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
> @@ -414,8 +414,8 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
> decoder->trace_on = false;
> break;
> case OCSD_GEN_TRC_ELEM_TRACE_ON:
> - resp = cs_etm_decoder__buffer_trace_on(decoder,
> - trace_chan_id);
> + resp = cs_etm_decoder__buffer_discontinuity(decoder,
> + trace_chan_id);
> decoder->trace_on = true;
> break;
> case OCSD_GEN_TRC_ELEM_INSTR_RANGE:
> 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 b295dd2..a272317 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 +23,9 @@ 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,
> + CS_ETM_RANGE,
> + CS_ETM_DISCONTINUITY,
> };

I'm in agreement with what you're doing in this patch but the above is a
different change and you can't pack it in here. Just split it off in a separate
patch and everything will be fine.

>
> enum cs_etm_isa {
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index ffc4fe5..cea3158 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -562,8 +562,8 @@ 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 the CS_ETM_DISCONTINUITY packet */
> + if (packet->sample_type == CS_ETM_DISCONTINUITY)
> return 0;
>
> return packet->start_addr;
> @@ -572,8 +572,8 @@ 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 the CS_ETM_DISCONTINUITY packet */
> + if (packet->sample_type == CS_ETM_DISCONTINUITY)
> return 0;
>
> return packet->end_addr - packet->last_instr_size;
> @@ -972,7 +972,7 @@ static int cs_etm__sample(struct cs_etm_queue *etmq)
> bool generate_sample = false;
>
> /* Generate sample for tracing on packet */
> - if (etmq->prev_packet->sample_type == CS_ETM_TRACE_ON)
> + if (etmq->prev_packet->sample_type == CS_ETM_DISCONTINUITY)
> generate_sample = true;
>
> /* Generate sample for branch taken packet */
> @@ -1148,7 +1148,7 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq)
> */
> cs_etm__sample(etmq);
> break;
> - case CS_ETM_TRACE_ON:
> + case CS_ETM_DISCONTINUITY:
> /*
> * Discontinuity in trace, flush
> * previous branch stack
> --
> 2.7.4
>