From: Matt Armstrong <matt@rfc20.org>
To: Pip Cet <pipcet@gmail.com>,
Stefan Monnier <monnier@iro.umontreal.ca>,
eliz@gnu.org
Cc: emacs-devel@gnu.org
Subject: Re: Opportunistic GC
Date: Wed, 10 Mar 2021 09:18:39 -0800 [thread overview]
Message-ID: <87lfav6i6o.fsf@rfc20.org> (raw)
In-Reply-To: <CAOqdjBfRJKN_nHLErVThMm7783rrhaHMBv+OmmiZXoaVKL-voQ@mail.gmail.com>
Pip Cet <pipcet@gmail.com> writes:
> On Mon, Mar 8, 2021 at 3:37 AM Stefan Monnier <monnier@iro.umontreal.ca> wrote:
>> I've been running with the code below recently to try and see if
>> opportunistic GC can be worth the trouble.
>
> Just a random idea: What if we exploit the fact most people have more
> than one CPU core these days, garbage-collect in a separate fork()ed
> process, then do only the sweeping in the main process?
>
> Immediate advantage: we'd never mark objects in the "real" Emacs
> process, making debugging easier.
>
> My implementation proposal would be to pipe(), fork(), run GC, then
> send through the pipe the Lisp_Objects which can be collected by the
> original Emacs.
>
> For me, it was a bit difficult to see that this would indeed be safe,
> but I'm now pretty convinced it would be: objects that are unreachable
> in the child Emacs cannot become reachable in the parent Emacs (they
> might show up on the stack, but that's a false positive).
>
> We'd have to be careful not to run two "real" GC processes at the same
> time.
Hi Pip,
Neat idea.
Are there examples of other GC implementations using this approach?
Perhaps this has been tried before, elsewhere, and we could learn a lot
from that.
I looked for myself and found
https://dlang.org/blog/2019/07/22/symmetry-autumn-of-code-experience-report-porting-a-fork-based-gc/
which talk about this idea in the context of the D run time. This page
mentions a different idea: doing the mark pass with multiple threads.
This might be worth exploring; the two ideas are composable with
each other.
Matt
next prev parent reply other threads:[~2021-03-10 17:18 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-08 3:35 Opportunistic GC Stefan Monnier
2021-03-08 7:20 ` Pip Cet
2021-03-08 8:26 ` martin rudalics
2021-03-08 9:02 ` Pip Cet
2021-03-08 9:51 ` martin rudalics
2021-03-08 10:44 ` Pip Cet
2021-03-08 11:37 ` martin rudalics
2021-03-08 12:27 ` Pip Cet
2021-03-08 18:06 ` martin rudalics
2021-03-08 18:24 ` Concurrent GC via fork (was: Opportunistic GC) Stefan Monnier
2021-03-09 8:10 ` Concurrent GC via fork martin rudalics
2021-03-10 20:35 ` Opportunistic GC Pip Cet
2021-03-08 11:38 ` Stefan Kangas
2021-03-08 12:55 ` Pip Cet
2021-03-08 14:06 ` Andrea Corallo via Emacs development discussions.
2021-03-08 14:49 ` Eli Zaretskii
2021-03-08 15:02 ` Pip Cet
2021-03-08 15:23 ` Eli Zaretskii
2021-03-08 15:39 ` Pip Cet
2021-03-08 16:27 ` Eli Zaretskii
2021-03-08 16:35 ` Pip Cet
2021-03-08 17:06 ` Eli Zaretskii
2021-03-08 15:46 ` Stefan Monnier
2021-03-08 16:11 ` Pip Cet
2021-03-08 16:37 ` Stefan Monnier
2021-03-08 14:01 ` Andrea Corallo via Emacs development discussions.
2021-03-08 15:04 ` Pip Cet
2021-03-08 15:50 ` Stefan Monnier
2021-03-08 15:52 ` Andrea Corallo via Emacs development discussions.
2021-03-08 16:14 ` Philipp Stephani
2021-03-08 16:18 ` Andrea Corallo via Emacs development discussions.
2021-03-08 16:40 ` Philipp Stephani
2021-03-08 16:44 ` Stefan Monnier
2021-03-08 17:13 ` Eli Zaretskii
2021-03-10 20:25 ` Pip Cet
2021-03-10 20:48 ` Eli Zaretskii
2021-03-11 7:55 ` Pip Cet
2021-03-11 8:37 ` Eli Zaretskii
2021-03-11 9:03 ` Pip Cet
2021-03-11 9:34 ` Eli Zaretskii
2021-03-11 10:11 ` Pip Cet
2021-03-11 11:35 ` Eli Zaretskii
2021-03-09 6:22 ` Richard Stallman
2021-03-09 8:11 ` Pip Cet
2021-03-10 5:52 ` Richard Stallman
2021-03-08 14:45 ` Eli Zaretskii
2021-03-08 14:57 ` Pip Cet
2021-03-08 15:16 ` Eli Zaretskii
2021-03-09 13:01 ` Eli Zaretskii
2021-03-10 20:21 ` Pip Cet
2021-03-10 20:41 ` Eli Zaretskii
2021-03-11 8:06 ` Pip Cet
2021-03-11 9:03 ` Eli Zaretskii
2021-03-08 16:03 ` Concurrent GC via `fork` (was: Opportunistic GC) Stefan Monnier
2021-03-08 16:25 ` Pip Cet
2021-03-08 17:37 ` Concurrent GC via `fork` Stefan Monnier
2021-03-08 19:21 ` Lars Ingebrigtsen
2021-03-10 17:18 ` Matt Armstrong [this message]
2021-03-10 19:38 ` Opportunistic GC Pip Cet
2022-07-05 1:47 ` Stefan Monnier
2022-07-05 13:49 ` T.V Raman
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