From: Nick Dokos <nicholas.dokos@hp.com>
To: Matt Price <moptop99@gmail.com>
Cc: help-gnu-emacs@gnu.org, nicholas.dokos@hp.com, emacs-orgmode@gnu.org
Subject: Re: diagnosing emacs hangs
Date: Tue, 22 Jun 2010 10:23:29 -0400 [thread overview]
Message-ID: <4061.1277216609@gamaville.dokosmarshall.org> (raw)
In-Reply-To: Message from Matt Price <moptop99@gmail.com> of "Mon, 21 Jun 2010 21:18:15 EDT." <AANLkTimza_Fv80ho01bsrbQSobtz3qZEod6jhaGssloo@mail.gmail.com>
Matt Price <moptop99@gmail.com> wrote:
> I'm now using emacs for almost everything and of course that's great,
> except that it is essentially a single-threaded OS that currently
> HANGS with some frequency (100% CPU usgte that will continue for hours
> if you let it go. I think this probably has something to do with
> wanderlust or possibly org-mode (and/or misconfigurations i've made to
> both of these); but at present i cna't be sure since i have no idea
> how to diagnose these hangs. Can someone give me some general
> directions on how to proceed with the diagnosis, and if you have them,
> some pointers on how you fixed a similar problem that you used to
> have? Right now it's very frustrating -- I find myself losing
> substantial amounts of work when I kill emacs & maybe more
> importantly, i'm constantly losing my train of thought.
>
> This is all under Ubuntu Lucid with emacs-snapshot 20090909,
> wanderlust=wl-beta 2.15.9+0.20100303, org-mode 6.34c (some of htese
> are debian sid packages).
>
I assume only emacs is stuck, so you can open an xterm: what does ``ps
awlx | grep emacs'' say? In particular, the state and the wchan are of
interest: normally, it should be in S state and waiting on select: idle
and waiting for input. If it's persistently in D state, it's stuck
somewhere in the kernel - the wchan gives an idea where. Do it a few times
to make sure that things are not changing.
The next step is to do ``strace -p<emacs_pid>'' to see whether it's going
in and out of the kernel (perhaps in an infinite loop).
If it is *not* going into the kernel, but accumulates CPU runtime (check
the ps awlx output a few times), then it's stuck in a loop in user
space. Attaching to it with ``gdb -p<emacs_pid>'' and getting a
backtrace should give an idea of where it's stuck. But if the loop is in
lisp code, the backtrace is not going to tell you where: it'll just be
in eval. If that's the case, then bisecting through your .emacs setup is
probably the best idea (maybe start by commenting out the org/wanderlust
stuff, particularly if you started getting these problems recently,
after making changes to their configuration.)
It's always a good idea to do these things with a working emacs first, so
that you learn what "normal" looks like. Then you have a better idea
of what's wrong when you try them on the stuck emacs.
This only scratches the surface but...
HTH,
Nick
prev parent reply other threads:[~2010-06-22 14:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-22 1:18 diagnosing emacs hangs Matt Price
2010-06-22 2:44 ` Qiang Guo
2010-06-22 6:04 ` Ian Barton
2010-06-22 10:05 ` Tassilo Horn
2010-06-22 14:23 ` Nick Dokos [this message]
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