Re: perf: store and retrieve trace event names in the perf.data file

[Arjan van de Ven]

Frederic Weisbecker wrote:
> On Sun, Aug 09, 2009 at 04:01:30PM -0700, Arjan van de Ven wrote:
> > Frederic Weisbecker wrote:
> > > On Sun, Aug 09, 2009 at 02:49:23PM -0700, Arjan van de Ven wrote:
> > > > In order to be able to use trace events, a key aspect is the "type" field;
> > > > this is the id of the event that you recorded, as stored in the /sys/kernel/debug/events/*/*/id file.
> > > > What is currently missing is a way to map the id number (which is not abi stable)
> > > > to the event that was recorded.
> > >
> > >
> > > We already have that.
> > > See tools/perf/util/parse-events.c: char *tracepoint_id_to_name(u64 id)
> >
> > sadly... we don't.
> >
> > You do it *on the same boot and machine* as you created the perf.data file.
> > You don't have it when you reboot into a new kernel, or move the perf.data file
> > to a new machine........
> >
> > Which is to be honest a very common usecase.
>
>
> Ah right... I always forget the offline report case.
> But you can at least reuse this existing helper to resolve
> the id to name.

ok I'll unstatic it, move it to a different file and ..

eh how about not?

this helper looks up an on disk id/name pair, and is private to it's existing file.
Fine.

The other one is based on the perf data, and all that is in header.c instead....


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