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: Mon, 21 Sep 2009 17:19:42 -0400 [thread overview]
Message-ID: <jwvfxagq9wv.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <m37hvvc10m.fsf@fleche.redhat.com> (Tom Tromey's message of "Fri, 18 Sep 2009 16:59:37 -0600")
> * Many, but not all, of the 9 kinds of variables that Emacs implements
> work properly with threads. In particular, working ones are
> defvaralias, objfwd, and ordinary. These all should do the right
> thing in all cases. Buffer-local and buffer objfwd mostly work,
> because we do buffer locking. (However, I think make-local-variable
> doesn't work properly with let-binding and multiple threads.) Not
> working on intfwd, boolfwd, keyboard-local and frame-local.
How do you handle objfwd objects? Do you swap them in&out during
context switches?
> * Buffer locking is actually quite a pain.
> If you have a background thread locking some buffer, you can't switch
> to that buffer. Emacs will just pause. I don't think we allow
> interrupting a lock acquisition (clearly a bug).
Yes, we may have to relax the locking somehow. E.g. we should clearly
allow to display a buffer in any window, if the buffer is "locked" by
a thread. I.e. things like switch-to-buffer should not take the
buffer's lock.
Of course, if the buffer is locked by a thread, we also need to be
careful what we do if the user then types a command in it (should we
wait for the thread to yield or should we signal an erreur?)
> * Giuseppe implemented minibuffer exclusion. But really the keyboard
> should only be available to one thread at a time.
You mean "each keyboard", right?
> Also, there are tons more problems if you want preemptive
> multithreading... redisplay probably needs work, regex is not
> reentrant, the GC needs a bit more work, you need lisp-level
> locks, etc.
Yes, lots of fun stuff, indeed.
> Sometimes I wonder whether it would be better to just fork a second
> emacs and communicate with it using pipes + princ + read. This uses
> more memory but the implementation would be a lot simpler and (I think)
> it would suffice for the one case that seems most important: Gnus.
But you can already do that right now, so it's a different "solution".
Stefan
next prev parent reply other threads:[~2009-09-21 21:19 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 [this message]
2009-09-21 21:50 ` Tom Tromey
2009-09-22 14:24 ` Stefan Monnier
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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