Re: [PATCH] perf parse: Allow names to start with digits

[Dominique Martinet <asmadeus@codewreck.org>]

Hi Jiri, Ian,

Jiri Olsa wrote on Mon, Jul 04, 2022 at 01:25:28PM +0200:
> > If you're ok with that I can resend this as three patches: my original
> > patch, a patch with your diff and test_event() keeping current
> > behaviour, and a last patch adding that last flag and testing 9p without
> > format check.
> > 
> > (and if you don't think it's worth checking probe existence same thing
> > but even simpler)
> 
> I have that patch split into 2 separated changes,
> I'll try to send it later today

It's been a while (I had totally forgotten), but I don't think I saw
this patch.

For reminder you've requested that I add some test for a tracepoint
starting with digits e.g. 9p:9p_client_res but there's nothing commonly
available to use there, so you added a way to only check without
checking if a backing tracepoint exist, but I see no trace of the update
you sent here:
https://lore.kernel.org/all/YsGduWiTvkM2/tHv@krava/

Should I take it, do the split you suggested and send it together with a
resend of my original patch and new test?


Ian Rogers wrote on Mon, Jul 04, 2022 at 02:39:05PM -0700:
> > diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
> > index 5b6e4b5249cf..4133d6950d29 100644
> > --- a/tools/perf/util/parse-events.l
> > +++ b/tools/perf/util/parse-events.l
> > @@ -211,7 +211,7 @@ bpf_source  [^,{}]+\.c[a-zA-Z0-9._]*
> >  num_dec                [0-9]+
> >  num_hex                0x[a-fA-F0-9]+
> >  num_raw_hex    [a-fA-F0-9]+
> > -name           [a-zA-Z_*?\[\]][a-zA-Z0-9_*?.\[\]!]*
> > +name           [a-zA-Z0-9_*?\[\]][a-zA-Z0-9_*?.\[\]!]*
> 
> Perhaps this would be cleaner as:
> name           [a-zA-Z0-9_*?\[\]!]+
> except that would allow a name to start with an exclamation. Would
> that be an issue?

Sorry for the lack of reply -- I have no opinion on this as long as we
can use digits.
I can't imagine any probe starting with . or !, but that does not seem
to create any ambiguity with the rest of the grammar that I can see
either so I think it'd be fine, but I'm not comfortable deciding.


Thanks,
--
Dominique