Re: [PATCH v2 2/5] perf arm-spe: Calculate meta data size

[Leo Yan]

On 9/27/24 07:14, Namhyung Kim wrote:
> Warning: EXTERNAL SENDER, use caution when opening links or attachments.
>
>
> On Sat, Sep 14, 2024 at 10:54:55PM +0100, Leo Yan wrote:
> > The metadata is designed to contain a header and per CPU information.
> >
> > The arm_spe_find_cpus() function is introduced to identify how many CPUs
> > support ARM SPE. Based on the CPU number, calculates the metadata size.
> >
> > Signed-off-by: Leo Yan <leo.yan@xxxxxxx>
> > ---
> >   tools/perf/arch/arm64/util/arm-spe.c | 35 +++++++++++++++++++++++++---
> >   1 file changed, 32 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
> > index c2d5c8ca4900..15478989ef30 100644
> > --- a/tools/perf/arch/arm64/util/arm-spe.c
> > +++ b/tools/perf/arch/arm64/util/arm-spe.c
> > @@ -37,11 +37,40 @@ struct arm_spe_recording {
> >        bool                    *wrapped;
> >   };
> >
> > +static struct perf_cpu_map *arm_spe_find_cpus(struct evlist *evlist)
>
> Please add a comment that it returns a new cpu map, and caller should
> release the reference after use.

Will do.

Thanks,
Leo

> > +{
> > +     struct perf_cpu_map *event_cpus = evlist->core.user_requested_cpus;
> > +     struct perf_cpu_map *online_cpus = perf_cpu_map__new_online_cpus();
> > +     struct perf_cpu_map *intersect_cpus;
> > +
> > +     /* cpu map is not "any" CPU , we have specific CPUs to work with */
> > +     if (!perf_cpu_map__has_any_cpu(event_cpus)) {
> > +             intersect_cpus = perf_cpu_map__intersect(event_cpus, online_cpus);
> > +             perf_cpu_map__put(online_cpus);
> > +     /* Event can be "any" CPU so count all CPUs. */
> > +     } else {
> > +             intersect_cpus = online_cpus;
> > +     }
> > +
> > +     return intersect_cpus;
> > +}