Re: [PATCH v2 1/4] perf-events: Add support for supplementary event registers

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Wed, 2011-03-02 at 08:48 +0100, Stephane Eranian wrote:
> >> >        __u32                   bp_type;
> >> > -       __u64                   bp_addr;
> >> > -       __u64                   bp_len;
> >> > +       union {
> >> > +               __u64           bp_addr;
> >> > +               __u64           config1; /* extension of config0 */
> >> > +       };
> >> > +       union {
> >> > +               __u64           bp_len;
> >> > +               __u64           config2; /* extension of config1 */
> >> > +       };
> >> >  };
> >> >
> >> I don't see where those config0 or config1 are coming from.
> >
> > config0 means perf_event_attr::config.
> >
> yes.
> 
> > Peter suggested to extend the attr config space.
> > http://marc.info/?l=linux-kernel&m=129838808907525&w=2
> >
> Ok, I get it, it is cascading. that's fine. 

I initially put config and config0 in a union, but that made compilation
fail and fixing that up vs the benefit of actually having a config0,
which seemed near 0, led me to drop that part. Forgot to update the
comment though ;-)