From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Uday S Reddy <u.s.reddy@cs.bham.ac.uk>
Cc: 5099@emacsbugs.donarmstrong.com
Subject: bug#5099: 23.1; Performance problems in Emacs 23?
Date: Wed, 02 Dec 2009 09:58:55 -0500 [thread overview]
Message-ID: <jwvy6ll1l53.fsf-monnier+emacsbugreports@gnu.org> (raw)
In-Reply-To: <84zl61daq4.fsf@cs.bham.ac.uk> (Uday S. Reddy's message of "Wed, 02 Dec 2009 08:46:43 +0000")
> However, having tried Emacs 23 for an hour, I have noticed very much
> the same phenomenon. My main mail file is roughly 100MB large.
> It takes Emacs 22 only about 5 seconds to save it, and the auto-save
> pause is probably half that long. (I use a reasonably fast Solid
> State Drive.) The CPU utilisation is an A-shaped curve, implying that
> there is nothing much for the CPU to do. In contrast, Emacs 23 takes
> about more than 20 seconds to save the same mail file and the CPU
> utilisation is a pretty intensive burn for most of that time (20% on
> one processor and 60% on a second processor). The auto-save pauses
> are about 10-15 seconds long.
> Now, VM mail files are raw-text. Saving them should be an I/O-bound
> process. It is not clear why Emacs 23 should be burning CPU cycles to
> save raw-text files and taking 3-5 times as long as Emacs 22.
That's indeed surprising and I can't think of anything that could cause
such a major slowdown. Maybe if the VM mail buffers (containing
"raw-text") are left in multibyte mode, we do something inefficient
somehow (but then again, it'd be surprising for those buffers to be in
multibyte mode anyway).
Stefan
next prev parent reply other threads:[~2009-12-02 14:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-02 8:46 bug#5099: 23.1; Performance problems in Emacs 23? Uday S Reddy
2009-12-02 14:58 ` Stefan Monnier [this message]
2014-02-03 0:17 ` Lars Ingebrigtsen
2014-02-03 16:31 ` Uday S Reddy
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