| Message ID | 1541912383-19915-4-git-send-email-leo.yan@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | perf cs-etm: Correct packets handling | expand |
On Sun, Nov 11, 2018 at 12:59:41PM +0800, Leo Yan wrote: > 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 Here you have used the word "almost", leading me to beleive there are cases where the handling of TRACE_ON and NO_SYNC packets differ, but the implementation enacts the same behavior for both. Mike or Robert, can you confirm that TRACE_ON and NO_SYNC packets should be treated the same way? Leo, if handling of the TRACE_ON and NO_SYNC packets is the same then we should treat them the same way in cs_etm_decoder__gen_trace_elem_printer(), i.e simply call cs_etm_decoder__buffer_trace_on(). That way packet handling in cs-etm.c doesn't change. Otherwise see my comments below. > 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); If we want to handle NO_SYNC element types, why introduce a "trace_off" function? Wouldn't it make more sense to call it cs_etm_decoder__buffer_no_sync() ? > 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, CS_ETM_NO_SYNC, see above comment. And please don't use indentation. > }; > > 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 > -- > 2.7.4 >
On Mon, Nov 19, 2018 at 11:27:59AM -0700, Mathieu Poirier wrote: > On Sun, Nov 11, 2018 at 12:59:41PM +0800, Leo Yan wrote: > > 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 > > Here you have used the word "almost", leading me to beleive there are cases > where the handling of TRACE_ON and NO_SYNC packets differ, but the > implementation enacts the same behavior for both. > > Mike or Robert, can you confirm that TRACE_ON and NO_SYNC packets should be > treated the same way? I also would like to get suggestions/comments from Mike and Rob. For NO_SYNC packet, Mike before has given some explination for it: "looking at the decoder flow, when the decoder is reset, then it is returned to an unsynchronised state and a NO_SYNC will be output. With perf, it can concatenate multiple trace buffers into a single section of the perf.data file. To ensure that the decode process can see the start of a new buffer, the drivers will insert a barrier packet between different buffers so that the decoder can spot the boundaries. When the decoder hits a barrier packet it will automatically reset so that it correctly decodes the next trace buffer. This could be what you are seeing here." So I think there still have some difference between TRACE_ON and NO_SYNC packets, TRACE_ON packet indicates the start of trace and it's also possible caused by tracing discontinuity; NO_SYNC packets usually caused by an unsynchronised state. But both of them presents discontinuity in perf trace data. I prefer to use two different packet types to present them, this can let the code to be more readable and easier to be maintained later. If you agree with this, I also will rephrase the commit log to avoid confusion that these two packets are the same thing. > Leo, if handling of the TRACE_ON and NO_SYNC packets is the same then we should > treat them the same way in cs_etm_decoder__gen_trace_elem_printer(), i.e simply > call cs_etm_decoder__buffer_trace_on(). That way packet handling in cs-etm.c > doesn't change. Otherwise see my comments below. > > > 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); > > If we want to handle NO_SYNC element types, why introduce a "trace_off" > function? Wouldn't it make more sense to call it > cs_etm_decoder__buffer_no_sync() ? Will change to cs_etm_decoder__buffer_no_sync(). > > 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, > > CS_ETM_NO_SYNC, see above comment. And please don't use indentation. Will do this. > > }; > > > > 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 > > -- > > 2.7.4 > >
On Tue, 4 Dec 2018 at 20:31, <leo.yan@linaro.org> wrote: > > On Mon, Nov 19, 2018 at 11:27:59AM -0700, Mathieu Poirier wrote: > > On Sun, Nov 11, 2018 at 12:59:41PM +0800, Leo Yan wrote: > > > 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 > > > > Here you have used the word "almost", leading me to beleive there are cases > > where the handling of TRACE_ON and NO_SYNC packets differ, but the > > implementation enacts the same behavior for both. > > > > Mike or Robert, can you confirm that TRACE_ON and NO_SYNC packets should be > > treated the same way? > > I also would like to get suggestions/comments from Mike and Rob. > > For NO_SYNC packet, Mike before has given some explination for it: > > "looking at the decoder flow, when the decoder is reset, then it is > returned to an unsynchronised state and a NO_SYNC will be output. > With perf, it can concatenate multiple trace buffers into a single > section of the perf.data file. To ensure that the decode process can > see the start of a new buffer, the drivers will insert a barrier > packet between different buffers so that the decoder can spot the > boundaries. When the decoder hits a barrier packet it will > automatically reset so that it correctly decodes the next trace > buffer. This could be what you are seeing here." > > So I think there still have some difference between TRACE_ON and > NO_SYNC packets, TRACE_ON packet indicates the start of trace and it's > also possible caused by tracing discontinuity; NO_SYNC packets usually > caused by an unsynchronised state. But both of them presents > discontinuity in perf trace data. > > I prefer to use two different packet types to present them, this can > let the code to be more readable and easier to be maintained later. Absolutely. Make sure to get to the bottom of the story with Mike and/or Robert before sending your next patchset. > > If you agree with this, I also will rephrase the commit log to avoid > confusion that these two packets are the same thing. Yes please. > > > Leo, if handling of the TRACE_ON and NO_SYNC packets is the same then we should > > treat them the same way in cs_etm_decoder__gen_trace_elem_printer(), i.e simply > > call cs_etm_decoder__buffer_trace_on(). That way packet handling in cs-etm.c > > doesn't change. Otherwise see my comments below. > > > > > 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); > > > > If we want to handle NO_SYNC element types, why introduce a "trace_off" > > function? Wouldn't it make more sense to call it > > cs_etm_decoder__buffer_no_sync() ? > > Will change to cs_etm_decoder__buffer_no_sync(). > > > > 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, > > > > CS_ETM_NO_SYNC, see above comment. And please don't use indentation. > > Will do this. > > > > }; > > > > > > 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 > > > -- > > > 2.7.4 > > >
On Wed, Dec 05, 2018 at 10:48:45AM -0700, Mathieu Poirier wrote: [...] > > So I think there still have some difference between TRACE_ON and > > NO_SYNC packets, TRACE_ON packet indicates the start of trace and it's > > also possible caused by tracing discontinuity; NO_SYNC packets usually > > caused by an unsynchronised state. But both of them presents > > discontinuity in perf trace data. > > > > I prefer to use two different packet types to present them, this can > > let the code to be more readable and easier to be maintained later. > > Absolutely. Make sure to get to the bottom of the story with Mike > and/or Robert before sending your next patchset. Sure, will sync with Mike/Rob. Thanks, Leo Yan
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
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(-)