From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Tom Tromey <tromey@redhat.com>
Cc: Emacs development discussions <emacs-devel@gnu.org>
Subject: Re: advice needed for multi-threading patch
Date: Tue, 22 Sep 2009 10:24:15 -0400 [thread overview]
Message-ID: <jwvab0nqdag.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <m3k4zsx907.fsf@fleche.redhat.com> (Tom Tromey's message of "Mon, 21 Sep 2009 15:50:32 -0600")
Stefan> How do you handle objfwd objects? Do you swap them in&out during
Stefan> context switches?
> We have a script to edit the Emacs source. In the end all DEFUN_LISP
> variables are defined like:
> #define Vafter_change_functions *find_variable_location (&impl_Vafter_change_functions)
Oh, right, I remember now, sorry.
> This works great as long as the C code follows lispy rules. However, I
> don't think that is always the case -- there are places doing direct
> assignment to some of these variables where, really, a per-thread
> assignment is meant.
I'm not sure what you mean. Are you still talking about objfwd
variables?
> We don't swap anything in and out during a context switch. I've tried
> to make all the decisions with an eye on the long term: preemptive
> threading. Ultimately I'd like to get rid of the global lock and have
> all threads run free.
That was the motivation for my question, indeed.
> Right now when a thread yields it does not release its buffer lock.
I think it should, unless some of the buffer-local variables are
let-bound by the thread.
> One way forward would be to work out the semantics properly, and
> eliminate buffer locking.
Yes, although the result of this may end up requiring some form of
buffer-locking, still.
> Some of the semantics seems tricky.
Oh, yes.
Stefan> You mean "each keyboard", right?
> Yes.
> Locking a keyboard will probably have strange effects. There are some
> things here that I have not thought through; like, what is the right
> behavior of debug-on-error? Under what conditions would the main thread
> ever release the keyboard?
Maybe another way to look at all these problems is to take an "agent"
point of view: rather than threads moving around, we could consider each
keyboard and each buffer as an active object (i.e. with its own thread),
which communicate among each other. I.e. a buffer-thread never leaves
its buffer, instead it does an RPC to another buffer-thread, or to
a keyboard-thread, ...
> Yeah. I just wonder why nobody has done it and whether it would not be
> a better approach.
IIUC people do it all the time, tho not with another Emacs process: with
an hexl process, a shell process, an openssl process, ...
Emacs currently is not very good at using stdin/stdout so running an
inferior Emacs process is poorly supported.
Stefan
next prev parent reply other threads:[~2009-09-22 14:24 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-26 4:38 advice needed for multi-threading patch Tom Tromey
2009-08-26 7:06 ` Ken Raeburn
2009-08-26 14:52 ` Stefan Monnier
2009-08-26 18:50 ` Ken Raeburn
2009-08-27 3:12 ` Stefan Monnier
2009-08-27 6:28 ` Ken Raeburn
2009-08-27 17:02 ` Stefan Monnier
2009-08-26 16:08 ` Tom Tromey
2009-08-26 18:50 ` Ken Raeburn
2009-08-27 5:07 ` Miles Bader
2009-08-27 6:39 ` Ken Raeburn
2009-08-27 6:50 ` Miles Bader
2009-08-28 20:48 ` Juri Linkov
2009-08-28 22:15 ` Miles Bader
2009-08-28 23:27 ` Juri Linkov
2009-08-28 23:54 ` Miles Bader
2009-08-29 20:21 ` Richard Stallman
2009-08-26 15:02 ` Stefan Monnier
2009-08-26 15:31 ` Tom Tromey
2009-08-26 19:18 ` Stefan Monnier
2009-09-18 22:59 ` Tom Tromey
2009-09-19 0:09 ` Stephen J. Turnbull
2009-09-19 0:32 ` Chong Yidong
2009-09-21 21:19 ` Stefan Monnier
2009-09-21 21:50 ` Tom Tromey
2009-09-22 14:24 ` Stefan Monnier [this message]
2009-09-22 23:59 ` Ken Raeburn
2009-09-23 3:11 ` Stefan Monnier
2009-09-23 15:53 ` Chong Yidong
2009-09-23 3:16 ` Tom Tromey
2009-09-24 17:25 ` Stefan Monnier
2009-09-24 17:57 ` Tom Tromey
2009-09-27 20:59 ` Tom Tromey
2009-09-27 23:05 ` Stefan Monnier
2009-09-28 4:27 ` Tom Tromey
2009-09-29 0:27 ` Stefan Monnier
2009-09-29 2:26 ` Ken Raeburn
2009-09-29 3:20 ` Stefan Monnier
2009-09-29 3:57 ` Ken Raeburn
2009-09-29 3:33 ` Tom Tromey
2009-09-29 4:07 ` Ken Raeburn
2009-09-29 2:30 ` Tom Tromey
2009-09-23 18:43 ` Giuseppe Scrivano
2009-09-24 17:29 ` Stefan Monnier
2009-09-24 18:53 ` Giuseppe Scrivano
2009-09-24 20:04 ` Tom Tromey
2009-09-24 21:59 ` Stefan Monnier
2009-09-24 22:23 ` Giuseppe Scrivano
2009-09-24 22:47 ` Ken Raeburn
2009-09-28 14:52 ` Ted Zlatanov
2009-10-05 6:02 ` joakim
2009-09-28 7:44 ` Lynbech Christian
2009-08-29 0:28 ` Giuseppe Scrivano
2009-08-29 4:57 ` Tom Tromey
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