Re: [PATCH v6 2/3] perf tools: Add lexical definition of event name

[Namhyung Kim <namhyung@kernel.org>]

On Mon, Feb 15, 2021 at 9:34 PM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Fri, Feb 12, 2021 at 06:03:17PM +0900, Shunsuke Nakamura wrote:
> > Add the lexical definition of event name so that the numbers are recognizable.
> >
> > A64FX defines an event name that starts with a number.
> >  - 0inst_commit
> >  - 1inst_commit
> >  - 2inst_commit
> >  - 3inst_commit
> >  - 4inst_commit
> >
> > Signed-off-by: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
> > ---
> >  tools/perf/util/parse-events.l | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
> > index 0b36285a9435..33f627187415 100644
> > --- a/tools/perf/util/parse-events.l
> > +++ b/tools/perf/util/parse-events.l
> > @@ -205,7 +205,7 @@ 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_*?.\[\]]*
>
> I can't see anything broken because of this change,
> also numbers are defined few lines before so we should
> be fine

But this change makes the syntax ambiguous with numbers
and names. I don't think it's a good idea.

Is it possible to change the event names not having numbers
at the beginning like inst_commit0, inst_commit1 and so on?

Thanks,
Namhyung