From: Tom Tromey <tom@tromey.com>
To: Paul Eggert <eggert@cs.ucla.edu>
Cc: Tom Tromey <tom@tromey.com>, emacs-devel@gnu.org
Subject: Re: Emacs Lisp JIT Compiler
Date: Mon, 13 Aug 2018 09:15:38 -0600 [thread overview]
Message-ID: <87pnym47s5.fsf@tromey.com> (raw)
In-Reply-To: <cdfe022a-cecc-dc4a-72c2-ae00f384ed3e@cs.ucla.edu> (Paul Eggert's message of "Sun, 12 Aug 2018 22:37:25 -0700")
>>>>> "Paul" == Paul Eggert <eggert@cs.ucla.edu> writes:
Paul> When you say "doesn't work", does that mean Emacs can reliably tell
Paul> the JIT won't work and fall back on the current bytecode
Paul> implementation, or something else?
What I meant is that when I wrote this, I didn't think about
--with-wide-int, and so some of the calls into libjit are incorrect for
that situation. It shouldn't be hard to fix.
>> libjit never frees functions. So, if a function is JIT-compiled
>> and then redefined, the old JIT code will linger. It's possible to fix
>> this with a custom allocator and a libjit patch (that I sent but that
>> hasn't been checked in yet).
Paul> libjit has only one committer, Aleksey, and no commits since March. Is
Paul> there a bottleneck there?
He's reasonably responsive, but it's true that the lack of an active
community around libjit is a bit of a risk. Mostly the problems would
be either (1) missing ports or (2) lack of improvements; for example,
libjit's register allocator is not very good, but nobody is working on
improving it.
It would be possible to switch to another JIT back end, but when I
looked into the various ones that are available, libjit was both easy to
use and reasonably lightweight (without being too lightweight, like GNU
Lightning).
But, for example, GCC has a JIT interface now. That could be used instead.
That seemed pretty heavy-weight to me; but I didn't really try it in
anger so maybe my fears are unfounded.
Tom
next prev parent reply other threads:[~2018-08-13 15:15 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-13 4:01 Emacs Lisp JIT Compiler Tom Tromey
2018-08-13 5:37 ` Paul Eggert
2018-08-13 15:15 ` Tom Tromey [this message]
2018-08-14 0:16 ` Tom Tromey
2018-08-14 20:11 ` Daniel Colascione
2018-08-14 20:55 ` Paul Eggert
2018-08-14 21:03 ` Daniel Colascione
2018-08-14 22:38 ` Paul Eggert
2018-08-15 16:41 ` Eli Zaretskii
2018-08-15 17:16 ` Paul Eggert
2018-08-15 17:47 ` Eli Zaretskii
2018-08-16 0:29 ` Tom Tromey
2018-08-16 13:26 ` Eli Zaretskii
2018-08-16 15:43 ` Daniel Colascione
2018-08-16 16:22 ` Andreas Schwab
2018-08-19 18:17 ` Tom Tromey
2018-08-19 19:00 ` Eli Zaretskii
2018-08-19 19:16 ` Tom Tromey
2018-08-19 20:23 ` Stefan Monnier
2018-08-18 10:10 ` Steinar Bang
2018-08-18 11:31 ` Eli Zaretskii
2018-08-19 10:00 ` Robert Pluim
2018-08-19 15:01 ` Eli Zaretskii
2018-08-19 15:26 ` Tom Tromey
2018-08-23 0:47 ` Tom Tromey
2018-08-23 16:48 ` Eli Zaretskii
2018-08-24 17:54 ` Tom Tromey
2018-08-24 20:23 ` Eli Zaretskii
2018-08-24 21:03 ` Tom Tromey
2018-08-25 6:51 ` Eli Zaretskii
2018-09-10 11:03 ` Ergus
2018-09-10 11:15 ` Robert Pluim
2018-09-10 11:53 ` Tom Tromey
2018-09-12 13:37 ` Robert Pluim
2018-09-13 4:32 ` Tom Tromey
2018-08-16 0:03 ` Tom Tromey
2018-08-16 2:45 ` Eli Zaretskii
2018-08-16 18:07 ` Eli Zaretskii
2018-08-13 13:50 ` T.V Raman
2018-08-13 15:18 ` Tom Tromey
2018-08-13 15:23 ` T.V Raman
2018-08-13 15:15 ` Eli Zaretskii
2018-08-20 21:54 ` John Wiegley
2018-08-13 23:31 ` Richard Stallman
2018-08-13 23:51 ` Tom Tromey
2018-08-16 2:42 ` Richard Stallman
2018-08-15 0:21 ` Clément Pit-Claudel
2018-08-16 0:32 ` Tom Tromey
2018-08-16 2:14 ` Clément Pit-Claudel
-- strict thread matches above, loose matches on Subject: below --
2016-12-11 17:37 Nickolas Lloyd
2016-12-12 6:07 ` John Wiegley
2016-12-12 11:51 ` Nickolas Lloyd
2016-12-12 16:45 ` John Wiegley
2016-12-23 17:22 ` Nickolas Lloyd
2016-12-13 22:24 ` Johan Bockgård
2016-12-05 18:16 Burton Samograd
2016-12-05 18:40 ` Eli Zaretskii
2016-12-05 19:32 ` Daniel Colascione
2016-12-05 21:03 ` Burton Samograd
2016-12-06 15:54 ` Lluís
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