Re: [PATCH v2 04/10] coresight: trbe: Ensure the format flag is set on truncation

[Suzuki K Poulose]

On 30/07/2021 05:26, Anshuman Khandual wrote:
> On 7/23/21 6:16 PM, Suzuki K Poulose wrote:
> > When the TRBE is stopped on truncating an event, we may not
> > set the FORMAT flag, even though the size of the record is 0.
> > Let us be consistent and not confuse the user. Always set the
> > format flag for TRBE generated records.
> >
> > Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> > Cc: Leo Yan <leo.yan@xxxxxxxxxx>
> > Cc: Mike Leach <mike.leach@xxxxxxxxxx>
> > Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > ---
> >   drivers/hwtracing/coresight/coresight-trbe.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
> > index 176868496879..446f080f8320 100644
> > --- a/drivers/hwtracing/coresight/coresight-trbe.c
> > +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> > @@ -132,7 +132,8 @@ static void trbe_stop_and_truncate_event(struct perf_output_handle *handle)
> >   	 * the update_buffer() to return a 0 size.
> >   	 */
> >   	trbe_drain_and_disable_local();
> > -	perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
> > +	perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED |
> > +				     PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW);
> >   	*this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL;
> >   }
>
> But why should not PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW also be set on
> zero sized records as well ? Otherwise there are two instances during
> TRBE buffer management, where PERF_AUX_FLAG_TRUNCATED is marked alone
> without PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW. Those could be changed as
> well.

All records (irrespective of the size) generated by the TRBE must
contain the "RAW" flag. Did I miss another instance where we don't
do this ?

Suzuki
>