Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 10 Oct 2022 14:38:54 +0900
From:   Dominique Martinet <asmadeus@codewreck.org>
To:     Jiri Olsa <olsajiri@gmail.com>, Ian Rogers <irogers@google.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Namhyung Kim <namhyung@kernel.org>,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jiri Olsa <jolsa@kernel.org>
Subject: Re: [PATCH] perf parse: Allow names to start with digits
Message-ID: <Y0Ov7hSuWQJlYAdW@codewreck.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <CAP-5=fXgNTW1eXRZhz-s_AfP+v1Oyx1zdksm-Q0B4YVPAgjKxw@mail.gmail.com>
 <YsLOKEqzp0Syz/Rt@krava>
Precedence: bulk

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