[llvm-dev] Email list just for front end developers?

Sat May 6 13:15:31 PDT 2017

On Sat, 6 May 2017 12:06:03 -0700 Sanjoy Das
<sanjoy at playingwithpointers.com> wrote:
> Hi,
> 
> On Sat, May 6, 2017 at 11:31 AM, Perry E. Metzger via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
> > It makes sense to have a place for us to talk to each other where
> > we're the dominant traffic, where our questions for each other
> > aren't concealed amidst a very large amount of traffic on Clang's
> > internals (or the rest of LLVM's), and where and our questions
> > unrelated to local concerns are not viewed as an annoyance.  
> 
> Why not just filter traffic on llvm-dev with "emails that haven't
> been replied to within a week"?  Right now llvm-dev is, say, ~220
> emails a week, so after that filter you should a small enough set
> of threads left which you can manually inspect.

I'm not sure that will work well, because people won't usually wait a
week to get their questions before moving on. If you're actively
working full time on a project, you probably want answers in much less
time.

Usually a question is inspired because you're trying to do something
immediately (say, in my own case, when I was working on real constants
and realized I couldn't find much documentation for what formats
APFloat understands when you pass the constructor a string), and
laying tools down for that long isn't an option. If no one answers in
less than a day, you probably have to go and slog through the
implementation on your own, which is of course sub-optimal.

> I don't think people will be annoyed by frontend specific questions
> on llvm-dev unless there is a very high number of them (unlikely),
> at which point we can //maybe// consider splitting out a new
> mailing list (but see below).

I doubt that there ever would be a lot of them as it stands, because I
think people find that they don't get answered and that they feel
weird about asking more questions of the same form. After a while a
culture gets entrenched.

Note that it isn't even something weird or inexplicable, I understand
why this sort of thing happens. llvm-dev serves a vital need already,
which is letting the llvm developers communicate with each other on
technical matters. Unusual traffic that isn't really any one person's
area gets less mental space.

So you get a dual problem either here or on the cfe lists, which is
that the normal traffic isn't traffic you understand (or care about)
and that the traffic that you are interested in isn't of much interest
to the overwhelming bulk of the list.

> > I would just like a place that makes self help among other people
> > in my position and that of the gentleman whose query I link to
> > above more likely to succeed.
>
> I agree that we do not do the best possible job in answering
> beginner questions, but is there something preventing you from
> changing that trend on llvm-dev, and making llvm-dev be that place
> where beginner questions are reliably answered?

Well, partially, I think, that it is hard to change a culture,
partially that llvm-dev isn't geared towards it (I myself don't
understand much of the traffic since I don't know anything past
IRBuilder well and am unlikely to dive into that soon, partially
because LLVM does such a good job at separating concerns that I don't
_have_ to understand the middle and back end work.)

However, if people think that just making a more determined effort to
answer newbie questions here is the best way to go, we can try, and
I'll certainly help, since I've been learning what many of them are
the hard way.

Again, though, I didn't even notice that message I posted asking for
help until long after that guy probably didn't care any more. It
probably remains hard answer such questions in an environment where
there's an impedance mismatch between the topics. As I noted, most of
the traffic here isn't even about stuff I understand well, I'm here
(and on the Clang lists) only because they're the closest thing to
what I actually _do_ need.

And again, the impedance mismatch is unlikely to be malice against
newcomers or any such thing. I think it's because, de facto, this is
where people discuss middle and back end development, and it is the
only good channel for that, and there's apparently a lot of that to
discuss.

> >> and I personally doubt you'd get as much expertise interested in
> >> order to keep it viable.
> >
> > Then it will fail. That's a risk with any new mailing list.
> > Luckily, the cost of mailing lists is very low, so the only risk
> > is that the list gets no traffic. If that happens, well, so be
> > it.
>
> There are other risks too - fragmentation (I have to sign up for yet
> another mailing list), discoverability (at this point many people
> already know about llvm-dev, how do they find out about the
> llvm-frontend-dev?).

Fragmentation is a real problem, especially since the people who are
often best equipped to answer the questions are people working on the
middle and back end. That could absolutely make this fail
hard. However, as it stands, such people often don't have much time to
answer anyway, or so it seems. To be sure, though, such an experiment
is most likely to fail for that reason.

I'm less worried about discoverability. One good post to the
announcements list and bit on LLVM weekly, and having it documented in
the normal places (lists.llvm.org, the various resources web pages)
should be enough.

And, if it fails, one can always turn it off, merge it back in, and
try something else. The cost is low.

But again, that said, if people really think that this is the right
place for such things and not a new list, that can probably be given a
good faith effort. My perception was that it probably wouldn't work
well because this list is de facto for something else, but I'm willing
to try if that's a strong consensus.

*That* said, I still think a Wiki would also be nice. When one finds a
hard-fought answer to a question, putting that answer somewhere beats
having the information only in people's heads. Yes, for sure, the
"right thing" is to submit a documentation patch, but there's a high
barrier involved for an outsider to do that, and putting the
information somewhere is better than having it nowhere. The only real
problem with a Wiki is it requires policing, they acquire spam at a
prodigious rate.

Perry
-- 
Perry E. Metzger		perry at piermont.com