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

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.
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(-)

-- 
2.7.4

Comments

Mathieu Poirier Nov. 19, 2018, 11:22 p.m. | #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. | #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. | #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 --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:
 					/*