
LuaJIT: New Garbage Collector (2012) - tosh
http://wiki.luajit.org/New-Garbage-Collector
======
SloopJon
Previous discussion, with comments from Mike Pall and Patrick Walton:

[https://news.ycombinator.com/item?id=4053969](https://news.ycombinator.com/item?id=4053969)

Github issue, which Mike said "is up for takers":

[https://github.com/LuaJIT/LuaJIT/issues/38](https://github.com/LuaJIT/LuaJIT/issues/38)

~~~
killercup
FYI: from 4.5 years ago

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beagle3
Mike Pall is a super hero. Not sure what his secret identity is, but the
origin story is
[http://www.pagetable.com/?p=656](http://www.pagetable.com/?p=656)

------
ufo
IIRC this project was abandoned after Mike Pall stepped down from LuaJIT
maintenance.

~~~
k__
What does he do right now?

~~~
zump
What's his day job? Internet is dark about this guy.

~~~
haberman
I've met Mike Pall in person. I've worked with him some since I helped
facilitate a sponsorship from Google
([https://opensource.googleblog.com/2010/01/love-for-
luajit.ht...](https://opensource.googleblog.com/2010/01/love-for-
luajit.html)). A lot of his work on LuaJIT has been supported by various
sponsorships (see:
[https://luajit.org/sponsors.html](https://luajit.org/sponsors.html)). This
gives him a lot of freedom to work the way he wants to, instead of working as
part of a larger organization.

Also note that the sponsorship page says that Mike is currently working on
"unrelated projects", so apparently things besides LuaJIT are keeping him busy
now.

~~~
chubot
What did he work on before LuaJIT? Seems like he could have been involved in
CPU design? He thinks more like a hardware guy than a C programmer.

~~~
haberman
I don't know that much about his background. I didn't get much of a chance to
talk shop with him (which is too bad, I would have loved to pick his brain
about all sorts of things). I also assume from the lack of info about him on
the Internet that he's a somewhat private person, so I definitely wanted/want
to respect that.

------
brudgers
Project updated as recently as June.
[http://wiki.luajit.org/latest_changes](http://wiki.luajit.org/latest_changes)

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omginternets
Is there something about lua that makes it amenable to the performance of
luaJIT? In priciple, would it be possible to get comparable performance out of
something like pypy?

In other words: is getting pypy to perform like luajit "just" a matter of
time/money/expertise, or are there technical considerations?

~~~
icebraining
Mike Pall said,

 _Well, nothing really. It 's just a matter of engineering, i.e. man-years put
into the VM and the compiler._

He has a few posts on Reddit regarding this subject:
[https://www.reddit.com/user/mikemike](https://www.reddit.com/user/mikemike)

~~~
Veedrac
That quote was in context of

 _What in your opinion keeps LuaJITs performance away from C /C++, i.e. what
other "hard" things need to be solved?_

~~~
omginternets
TBH that was the spirit of my question. I was wondering if there was something
special about Lua (the language), and it seems like the answer is a resounding
"no".

So basically, I should donate to pypy...

~~~
Veedrac
I'm not sure I could call that "resounding" \- for one a PyPy dev disagreed
with him in a sibling thread.

> Yes, you can go a long way without extra APIs etc, but sometimes there is
> info that's available, that's simply not there, because it's only in a
> programmers head.

[https://www.reddit.com/r/programming/comments/19gv4c/why_pyt...](https://www.reddit.com/r/programming/comments/19gv4c/why_python_ruby_and_js_are_slow/c8owc5t/)

------
wsmith
_The new garbage collector should be based on well-researched and proven
algorithms, together with a couple of thoroughly evaluated innovations, where
appropriate. The real innovation should be in the specific mix of techniques,
forming a coherent and well-balanced system, with meticulous attention to
detail and relentless optimization for performance._

Sometimes I feel there's an inverse correlation between the strength of claims
for the future and the end result.

