Re: [RFC 02/11] coresight: etm-perf: Allow an event to use different sinks

[Suzuki K Poulose]

On 11/12/20 10:37 AM, Linu Cherian wrote:
> Hi Suzuki,
>
> On Thu, Nov 12, 2020 at 2:51 PM Suzuki K Poulose <suzuki.poulose@xxxxxxx> wrote:
> > Hi Linu,
> >
> > Please could you test this slightly modified version and give us
> > a Tested-by tag if you are happy with the results ?
> >
> > Suzuki
> >
> >
> > On 11/10/20 12:45 PM, Anshuman Khandual wrote:
> > > From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > >
> > > When there are multiple sinks on the system, in the absence
> > > of a specified sink, it is quite possible that a default sink
> > > for an ETM could be different from that of another ETM. However
> > > we do not support having multiple sinks for an event yet. This
> > > patch allows the event to use the default sinks on the ETMs
> > > where they are scheduled as long as the sinks are of the same
> > > type.
> > >
> > > e.g, if we have 1x1 topology with per-CPU ETRs, the event can
> > > use the per-CPU ETR for the session. However, if the sinks
> > > are of different type, e.g TMC-ETR on one and a custom sink
> > > on another, the event will only trace on the first detected
> > > sink.
> > >
> > > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > > Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> > > ---


> > > @@ -284,7 +307,12 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
> > >        if (!sink_ops(sink)->alloc_buffer || !sink_ops(sink)->free_buffer)
> > >                goto err;
> > >
> > > -     /* Allocate the sink buffer for this session */
> > > +     /*
> > > +      * Allocate the sink buffer for this session. All the sinks
> > > +      * where this event can be scheduled are ensured to be of the
> > > +      * same type. Thus the same sink configuration is used by the
> > > +      * sinks.
> > > +      */
> > >        event_data->snk_config =
> > >                        sink_ops(sink)->alloc_buffer(sink, event, pages,
> > >                                                     nr_pages, overwrite);
>
> Perf record and report worked fine with this as well, with formatting
> related opencsd hacks.
>
> Tested-by : Linu Cherian <lcherian@xxxxxxxxxxx>

Thanks Linu, much appreciated.

Suzuki