[v2,2/2] perf cs-etm: Add support sample flags
diff mbox series

Message ID 1541912876-20967-3-git-send-email-leo.yan@linaro.org
State New
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Series
  • perf cs-etm: Add support for sample flags
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Commit Message

Leo Yan Nov. 11, 2018, 5:07 a.m. UTC
We have prepared the flags in the packet structure, so need to copy
the related value into sample structure thus perf tool can facilitate
sample flags.

The PREV_PACKET contains the branch instruction flags and PACKET
actually contains the flags for next branch instruction.  So this patch
is to set sample flags with 'etmq->prev_packet->flags'.

This patch includes three fixing up for sample flags based on the
packets context:

- If the packet is exception packet or exception return packet, update
  the previous packet for exception specific flags;
- If there has TRACE_ON or TRACE_OFF packet in the middle of instruction
  packets, this indicates the trace is discontinuous, so append the flag
  PERF_IP_FLAG_TRACE_END to the previous packet to indicate the trace
  has been ended;
- If one instruction packet is behind TRACE_OFF packet, this instruction
  is restarting trace packet.  So set flag PERF_IP_FLAG_TRACE_START to
  TRACE_OFF packet if one, this flag isn't used by TRACE_OFF packet but
  used to indicate trace restarting when generate sample.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 tools/perf/util/cs-etm.c | 43 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 41 insertions(+), 2 deletions(-)

Comments

Mathieu Poirier Nov. 19, 2018, 11:22 p.m. UTC | #1
On Sun, Nov 11, 2018 at 01:07:56PM +0800, Leo Yan wrote:
> We have prepared the flags in the packet structure, so need to copy
> the related value into sample structure thus perf tool can facilitate
> sample flags.
> 
> The PREV_PACKET contains the branch instruction flags and PACKET
> actually contains the flags for next branch instruction.  So this patch
> is to set sample flags with 'etmq->prev_packet->flags'.
> 
> This patch includes three fixing up for sample flags based on the
> packets context:
> 
> - If the packet is exception packet or exception return packet, update
>   the previous packet for exception specific flags;
> - If there has TRACE_ON or TRACE_OFF packet in the middle of instruction
>   packets, this indicates the trace is discontinuous, so append the flag
>   PERF_IP_FLAG_TRACE_END to the previous packet to indicate the trace
>   has been ended;
> - If one instruction packet is behind TRACE_OFF packet, this instruction
>   is restarting trace packet.  So set flag PERF_IP_FLAG_TRACE_START to
>   TRACE_OFF packet if one, this flag isn't used by TRACE_OFF packet but
>   used to indicate trace restarting when generate sample.
> 
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> ---
>  tools/perf/util/cs-etm.c | 43 +++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 41 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index 455f132..afca6f3 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -676,7 +676,7 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,
>  	sample.stream_id = etmq->etm->instructions_id;
>  	sample.period = period;
>  	sample.cpu = etmq->packet->cpu;
> -	sample.flags = 0;
> +	sample.flags = etmq->prev_packet->flags;
>  	sample.insn_len = 1;
>  	sample.cpumode = event->sample.header.misc;
>  
> @@ -735,7 +735,7 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq)
>  	sample.stream_id = etmq->etm->branches_id;
>  	sample.period = 1;
>  	sample.cpu = etmq->packet->cpu;
> -	sample.flags = 0;
> +	sample.flags = etmq->prev_packet->flags;
>  	sample.cpumode = event->sample.header.misc;
>  
>  	/*
> @@ -878,6 +878,43 @@ static int cs_etm__synth_events(struct cs_etm_auxtrace *etm,
>  	return 0;
>  }
>  
> +static void cs_etm__fixup_flags(struct cs_etm_queue *etmq)
> +{
> +	/*
> +	 * Decoding stream might insert one TRACE_OFF packet in the
> +	 * middle of instruction packets, this means it doesn't
> +	 * contain the pair packets with TRACE_OFF and TRACE_ON.
> +	 * For this case, the instruction packet follows with
> +	 * TRACE_OFF packet so we need to fixup prev_packet with flag
> +	 * PERF_IP_FLAG_TRACE_BEGIN, this flag finally is used by the
> +	 * instruction packet to generate samples.
> +	 */
> +	if (etmq->prev_packet->sample_type == CS_ETM_TRACE_OFF &&
> +	    etmq->packet->sample_type == CS_ETM_RANGE)
> +		etmq->prev_packet->flags = PERF_IP_FLAG_BRANCH |
> +					   PERF_IP_FLAG_TRACE_BEGIN;
> +
> +	if (etmq->prev_packet->sample_type == CS_ETM_RANGE) {
> +		/*
> +		 * When the exception packet is inserted, update flags
> +		 * so tell perf it is exception related branches.
> +		 */
> +		if (etmq->packet->sample_type == CS_ETM_EXCEPTION ||
> +		    etmq->packet->sample_type == CS_ETM_EXCEPTION_RET)
> +			etmq->prev_packet->flags = etmq->packet->flags;
> +
> +		/*
> +		 * The trace is discontinuous, weather this is caused by
> +		 * TRACE_ON packet or TRACE_OFF packet is coming, if the
> +		 * previous packet is instruction packet, simply set flag
> +		 * PERF_IP_FLAG_TRACE_END for previous packet.
> +		 */
> +		if (etmq->packet->sample_type == CS_ETM_TRACE_ON ||
> +		    etmq->packet->sample_type == CS_ETM_TRACE_OFF)
> +			etmq->prev_packet->flags |= PERF_IP_FLAG_TRACE_END;
> +	}
> +}
> +

I think it would be better to keep all the flag related processing in
cs-etm-decoder.c so that things in cs-etm.c are only concered with dealing with
perf.

Look at function cs_etm__alloc_queue(), there you'll find "d_params.data = etmq".

In function cs_etm_decoder__new(), decoder->data = d_params->data;

This means that anywhere you have a decoder, decoder->data is an etmq.  I've
used this profusely in my work on CPU-wide trace scenarios.  Because you're
getting there ahead of me you'll need to fix the declaration of struct
cs_etm_queue but that's easy.

Regards,
Mathieu 

>  static int cs_etm__sample(struct cs_etm_queue *etmq)
>  {
>  	struct cs_etm_auxtrace *etm = etmq->etm;
> @@ -1100,6 +1137,8 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq)
>  					 */
>  					break;
>  
> +				cs_etm__fixup_flags(etmq);
> +
>  				switch (etmq->packet->sample_type) {
>  				case CS_ETM_RANGE:
>  					/*
> -- 
> 2.7.4
>
Mathieu Poirier Nov. 20, 2018, 4:53 p.m. UTC | #2
On Mon, 19 Nov 2018 at 16:22, Mathieu Poirier
<mathieu.poirier@linaro.org> wrote:
>
> On Sun, Nov 11, 2018 at 01:07:56PM +0800, Leo Yan wrote:
> > We have prepared the flags in the packet structure, so need to copy
> > the related value into sample structure thus perf tool can facilitate
> > sample flags.
> >
> > The PREV_PACKET contains the branch instruction flags and PACKET
> > actually contains the flags for next branch instruction.  So this patch
> > is to set sample flags with 'etmq->prev_packet->flags'.
> >
> > This patch includes three fixing up for sample flags based on the
> > packets context:
> >
> > - If the packet is exception packet or exception return packet, update
> >   the previous packet for exception specific flags;
> > - If there has TRACE_ON or TRACE_OFF packet in the middle of instruction
> >   packets, this indicates the trace is discontinuous, so append the flag
> >   PERF_IP_FLAG_TRACE_END to the previous packet to indicate the trace
> >   has been ended;
> > - If one instruction packet is behind TRACE_OFF packet, this instruction
> >   is restarting trace packet.  So set flag PERF_IP_FLAG_TRACE_START to
> >   TRACE_OFF packet if one, this flag isn't used by TRACE_OFF packet but
> >   used to indicate trace restarting when generate sample.
> >
> > Signed-off-by: Leo Yan <leo.yan@linaro.org>
> > ---
> >  tools/perf/util/cs-etm.c | 43 +++++++++++++++++++++++++++++++++++++++++--
> >  1 file changed, 41 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> > index 455f132..afca6f3 100644
> > --- a/tools/perf/util/cs-etm.c
> > +++ b/tools/perf/util/cs-etm.c
> > @@ -676,7 +676,7 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,
> >       sample.stream_id = etmq->etm->instructions_id;
> >       sample.period = period;
> >       sample.cpu = etmq->packet->cpu;
> > -     sample.flags = 0;
> > +     sample.flags = etmq->prev_packet->flags;
> >       sample.insn_len = 1;
> >       sample.cpumode = event->sample.header.misc;
> >
> > @@ -735,7 +735,7 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq)
> >       sample.stream_id = etmq->etm->branches_id;
> >       sample.period = 1;
> >       sample.cpu = etmq->packet->cpu;
> > -     sample.flags = 0;
> > +     sample.flags = etmq->prev_packet->flags;
> >       sample.cpumode = event->sample.header.misc;
> >
> >       /*
> > @@ -878,6 +878,43 @@ static int cs_etm__synth_events(struct cs_etm_auxtrace *etm,
> >       return 0;
> >  }
> >
> > +static void cs_etm__fixup_flags(struct cs_etm_queue *etmq)
> > +{
> > +     /*
> > +      * Decoding stream might insert one TRACE_OFF packet in the
> > +      * middle of instruction packets, this means it doesn't
> > +      * contain the pair packets with TRACE_OFF and TRACE_ON.
> > +      * For this case, the instruction packet follows with
> > +      * TRACE_OFF packet so we need to fixup prev_packet with flag
> > +      * PERF_IP_FLAG_TRACE_BEGIN, this flag finally is used by the
> > +      * instruction packet to generate samples.
> > +      */
> > +     if (etmq->prev_packet->sample_type == CS_ETM_TRACE_OFF &&
> > +         etmq->packet->sample_type == CS_ETM_RANGE)
> > +             etmq->prev_packet->flags = PERF_IP_FLAG_BRANCH |
> > +                                        PERF_IP_FLAG_TRACE_BEGIN;
> > +
> > +     if (etmq->prev_packet->sample_type == CS_ETM_RANGE) {
> > +             /*
> > +              * When the exception packet is inserted, update flags
> > +              * so tell perf it is exception related branches.
> > +              */
> > +             if (etmq->packet->sample_type == CS_ETM_EXCEPTION ||
> > +                 etmq->packet->sample_type == CS_ETM_EXCEPTION_RET)
> > +                     etmq->prev_packet->flags = etmq->packet->flags;
> > +
> > +             /*
> > +              * The trace is discontinuous, weather this is caused by
> > +              * TRACE_ON packet or TRACE_OFF packet is coming, if the
> > +              * previous packet is instruction packet, simply set flag
> > +              * PERF_IP_FLAG_TRACE_END for previous packet.
> > +              */
> > +             if (etmq->packet->sample_type == CS_ETM_TRACE_ON ||
> > +                 etmq->packet->sample_type == CS_ETM_TRACE_OFF)
> > +                     etmq->prev_packet->flags |= PERF_IP_FLAG_TRACE_END;
> > +     }
> > +}
> > +
>
> I think it would be better to keep all the flag related processing in
> cs-etm-decoder.c so that things in cs-etm.c are only concered with dealing with
> perf.
>
> Look at function cs_etm__alloc_queue(), there you'll find "d_params.data = etmq".
>
> In function cs_etm_decoder__new(), decoder->data = d_params->data;
>
> This means that anywhere you have a decoder, decoder->data is an etmq.  I've
> used this profusely in my work on CPU-wide trace scenarios.  Because you're
> getting there ahead of me you'll need to fix the declaration of struct
> cs_etm_queue but that's easy.

I've been thinking further about this and manipulating the etmq packet
and prev_packet from the cs-etm-decoder.c won't work because all we
have at that time is the decoder's packet queue.  My goal is to
manipulate the flags in only one place - either in cs-etm.c or
cs-etm-decoder.c but not in both.  It might be worth trying to do the
implementation in cs-etm.c since there is already a lot of packet flow
intelligence happening there.

>
> Regards,
> Mathieu
>
> >  static int cs_etm__sample(struct cs_etm_queue *etmq)
> >  {
> >       struct cs_etm_auxtrace *etm = etmq->etm;
> > @@ -1100,6 +1137,8 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq)
> >                                        */
> >                                       break;
> >
> > +                             cs_etm__fixup_flags(etmq);
> > +
> >                               switch (etmq->packet->sample_type) {
> >                               case CS_ETM_RANGE:
> >                                       /*
> > --
> > 2.7.4
> >
Leo Yan Dec. 5, 2018, 6:38 a.m. UTC | #3
On Tue, Nov 20, 2018 at 09:53:41AM -0700, Mathieu Poirier wrote:

[...]

> > > +static void cs_etm__fixup_flags(struct cs_etm_queue *etmq)
> > > +{
> > > +     /*
> > > +      * Decoding stream might insert one TRACE_OFF packet in the
> > > +      * middle of instruction packets, this means it doesn't
> > > +      * contain the pair packets with TRACE_OFF and TRACE_ON.
> > > +      * For this case, the instruction packet follows with
> > > +      * TRACE_OFF packet so we need to fixup prev_packet with flag
> > > +      * PERF_IP_FLAG_TRACE_BEGIN, this flag finally is used by the
> > > +      * instruction packet to generate samples.
> > > +      */
> > > +     if (etmq->prev_packet->sample_type == CS_ETM_TRACE_OFF &&
> > > +         etmq->packet->sample_type == CS_ETM_RANGE)
> > > +             etmq->prev_packet->flags = PERF_IP_FLAG_BRANCH |
> > > +                                        PERF_IP_FLAG_TRACE_BEGIN;
> > > +
> > > +     if (etmq->prev_packet->sample_type == CS_ETM_RANGE) {
> > > +             /*
> > > +              * When the exception packet is inserted, update flags
> > > +              * so tell perf it is exception related branches.
> > > +              */
> > > +             if (etmq->packet->sample_type == CS_ETM_EXCEPTION ||
> > > +                 etmq->packet->sample_type == CS_ETM_EXCEPTION_RET)
> > > +                     etmq->prev_packet->flags = etmq->packet->flags;
> > > +
> > > +             /*
> > > +              * The trace is discontinuous, weather this is caused by
> > > +              * TRACE_ON packet or TRACE_OFF packet is coming, if the
> > > +              * previous packet is instruction packet, simply set flag
> > > +              * PERF_IP_FLAG_TRACE_END for previous packet.
> > > +              */
> > > +             if (etmq->packet->sample_type == CS_ETM_TRACE_ON ||
> > > +                 etmq->packet->sample_type == CS_ETM_TRACE_OFF)
> > > +                     etmq->prev_packet->flags |= PERF_IP_FLAG_TRACE_END;
> > > +     }
> > > +}
> > > +
> >
> > I think it would be better to keep all the flag related processing in
> > cs-etm-decoder.c so that things in cs-etm.c are only concered with dealing with
> > perf.
> >
> > Look at function cs_etm__alloc_queue(), there you'll find "d_params.data = etmq".
> >
> > In function cs_etm_decoder__new(), decoder->data = d_params->data;
> >
> > This means that anywhere you have a decoder, decoder->data is an etmq.  I've
> > used this profusely in my work on CPU-wide trace scenarios.  Because you're
> > getting there ahead of me you'll need to fix the declaration of struct
> > cs_etm_queue but that's easy.
> 
> I've been thinking further about this and manipulating the etmq packet
> and prev_packet from the cs-etm-decoder.c won't work because all we
> have at that time is the decoder's packet queue.  My goal is to
> manipulate the flags in only one place - either in cs-etm.c or
> cs-etm-decoder.c but not in both.  It might be worth trying to do the
> implementation in cs-etm.c since there is already a lot of packet flow
> intelligence happening there.

Agree.  cs-etm.c has more context info than cs-etm-decoder.c, will
try to refactor in single place in cs-etm.c.

[...]

Thanks,
Leo Yan

Patch
diff mbox series

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 455f132..afca6f3 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -676,7 +676,7 @@  static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,
 	sample.stream_id = etmq->etm->instructions_id;
 	sample.period = period;
 	sample.cpu = etmq->packet->cpu;
-	sample.flags = 0;
+	sample.flags = etmq->prev_packet->flags;
 	sample.insn_len = 1;
 	sample.cpumode = event->sample.header.misc;
 
@@ -735,7 +735,7 @@  static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq)
 	sample.stream_id = etmq->etm->branches_id;
 	sample.period = 1;
 	sample.cpu = etmq->packet->cpu;
-	sample.flags = 0;
+	sample.flags = etmq->prev_packet->flags;
 	sample.cpumode = event->sample.header.misc;
 
 	/*
@@ -878,6 +878,43 @@  static int cs_etm__synth_events(struct cs_etm_auxtrace *etm,
 	return 0;
 }
 
+static void cs_etm__fixup_flags(struct cs_etm_queue *etmq)
+{
+	/*
+	 * Decoding stream might insert one TRACE_OFF packet in the
+	 * middle of instruction packets, this means it doesn't
+	 * contain the pair packets with TRACE_OFF and TRACE_ON.
+	 * For this case, the instruction packet follows with
+	 * TRACE_OFF packet so we need to fixup prev_packet with flag
+	 * PERF_IP_FLAG_TRACE_BEGIN, this flag finally is used by the
+	 * instruction packet to generate samples.
+	 */
+	if (etmq->prev_packet->sample_type == CS_ETM_TRACE_OFF &&
+	    etmq->packet->sample_type == CS_ETM_RANGE)
+		etmq->prev_packet->flags = PERF_IP_FLAG_BRANCH |
+					   PERF_IP_FLAG_TRACE_BEGIN;
+
+	if (etmq->prev_packet->sample_type == CS_ETM_RANGE) {
+		/*
+		 * When the exception packet is inserted, update flags
+		 * so tell perf it is exception related branches.
+		 */
+		if (etmq->packet->sample_type == CS_ETM_EXCEPTION ||
+		    etmq->packet->sample_type == CS_ETM_EXCEPTION_RET)
+			etmq->prev_packet->flags = etmq->packet->flags;
+
+		/*
+		 * The trace is discontinuous, weather this is caused by
+		 * TRACE_ON packet or TRACE_OFF packet is coming, if the
+		 * previous packet is instruction packet, simply set flag
+		 * PERF_IP_FLAG_TRACE_END for previous packet.
+		 */
+		if (etmq->packet->sample_type == CS_ETM_TRACE_ON ||
+		    etmq->packet->sample_type == CS_ETM_TRACE_OFF)
+			etmq->prev_packet->flags |= PERF_IP_FLAG_TRACE_END;
+	}
+}
+
 static int cs_etm__sample(struct cs_etm_queue *etmq)
 {
 	struct cs_etm_auxtrace *etm = etmq->etm;
@@ -1100,6 +1137,8 @@  static int cs_etm__run_decoder(struct cs_etm_queue *etmq)
 					 */
 					break;
 
+				cs_etm__fixup_flags(etmq);
+
 				switch (etmq->packet->sample_type) {
 				case CS_ETM_RANGE:
 					/*