2020-02-03 01:54:00

by Leo Yan

Subject: [PATCH v3 1/5] perf cs-etm: Swap packets for instruction samples

If use option '--itrace=iNNN' with Arm CoreSight trace data, perf tool
fails inject instruction samples; the root cause is the packets are
only switched for branch samples and last branches but not for
instruction samples, so the new coming packets cannot be properly
handled for only synthesizing instruction samples.

To fix this issue, this patch switches packets for instruction samples.

Signed-off-by: Leo Yan <[email protected]>
---
tools/perf/util/cs-etm.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 5471045ebf5c..3dd5ba34a2c2 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -1404,7 +1404,8 @@ static int cs_etm__sample(struct cs_etm_queue *etmq,
}
}

- if (etm->sample_branches || etm->synth_opts.last_branch) {
+ if (etm->sample_branches || etm->synth_opts.last_branch ||
+ etm->sample_instructions) {
/*
* Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
* the next incoming packet.
@@ -1476,7 +1477,8 @@ static int cs_etm__flush(struct cs_etm_queue *etmq,
}

swap_packet:
- if (etm->sample_branches || etm->synth_opts.last_branch) {
+ if (etm->sample_branches || etm->synth_opts.last_branch ||
+ etm->sample_instructions) {
/*
* Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
* the next incoming packet.
--
2.17.1

2020-02-05 16:01:25

by Mike Leach

Subject: Re: [PATCH v3 1/5] perf cs-etm: Swap packets for instruction samples

Hi Leo

On Mon, 3 Feb 2020 at 01:52, Leo Yan <[email protected]> wrote:
>
> If use option '--itrace=iNNN' with Arm CoreSight trace data, perf tool
> fails inject instruction samples; the root cause is the packets are
> only switched for branch samples and last branches but not for
> instruction samples, so the new coming packets cannot be properly
> handled for only synthesizing instruction samples.
>
> To fix this issue, this patch switches packets for instruction samples.
>
> Signed-off-by: Leo Yan <[email protected]>
> ---
> tools/perf/util/cs-etm.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index 5471045ebf5c..3dd5ba34a2c2 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -1404,7 +1404,8 @@ static int cs_etm__sample(struct cs_etm_queue *etmq,
> }
> }
>
> - if (etm->sample_branches || etm->synth_opts.last_branch) {
> + if (etm->sample_branches || etm->synth_opts.last_branch ||
> + etm->sample_instructions) {
> /*
> * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
> * the next incoming packet.
> @@ -1476,7 +1477,8 @@ static int cs_etm__flush(struct cs_etm_queue *etmq,
> }
>
> swap_packet:
> - if (etm->sample_branches || etm->synth_opts.last_branch) {
> + if (etm->sample_branches || etm->synth_opts.last_branch ||
> + etm->sample_instructions) {
> /*
> * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
> * the next incoming packet.
> --
> 2.17.1
>
if is worth putting the 'if <options> { swap packet }' into a separate
function as it appears twice in identical form? Might help if more
options for swap packet are needed later.

Either way

Reviewed by: Mike Leach <[email protected]>


--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK

2020-02-06 07:48:42

by Leo Yan

Subject: Re: [PATCH v3 1/5] perf cs-etm: Swap packets for instruction samples

Hi Mike,

On Wed, Feb 05, 2020 at 03:59:40PM +0000, Mike Leach wrote:
> Hi Leo
>
> On Mon, 3 Feb 2020 at 01:52, Leo Yan <[email protected]> wrote:
> >
> > If use option '--itrace=iNNN' with Arm CoreSight trace data, perf tool
> > fails inject instruction samples; the root cause is the packets are
> > only switched for branch samples and last branches but not for
> > instruction samples, so the new coming packets cannot be properly
> > handled for only synthesizing instruction samples.
> >
> > To fix this issue, this patch switches packets for instruction samples.
> >
> > Signed-off-by: Leo Yan <[email protected]>
> > ---
> > tools/perf/util/cs-etm.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> > index 5471045ebf5c..3dd5ba34a2c2 100644
> > --- a/tools/perf/util/cs-etm.c
> > +++ b/tools/perf/util/cs-etm.c
> > @@ -1404,7 +1404,8 @@ static int cs_etm__sample(struct cs_etm_queue *etmq,
> > }
> > }
> >
> > - if (etm->sample_branches || etm->synth_opts.last_branch) {
> > + if (etm->sample_branches || etm->synth_opts.last_branch ||
> > + etm->sample_instructions) {
> > /*
> > * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
> > * the next incoming packet.
> > @@ -1476,7 +1477,8 @@ static int cs_etm__flush(struct cs_etm_queue *etmq,
> > }
> >
> > swap_packet:
> > - if (etm->sample_branches || etm->synth_opts.last_branch) {
> > + if (etm->sample_branches || etm->synth_opts.last_branch ||
> > + etm->sample_instructions) {
> > /*
> > * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
> > * the next incoming packet.
> > --
> > 2.17.1
> >
> if is worth putting the 'if <options> { swap packet }' into a separate
> function as it appears twice in identical form? Might help if more
> options for swap packet are needed later.

Makes sense. Will factor out a new function for this.

Thanks for reviewing!
Leo

> Either way
>
> Reviewed by: Mike Leach <[email protected]>
>
>
> --
> Mike Leach
> Principal Engineer, ARM Ltd.
> Manchester Design Centre. UK