Re: emacs mode performance issue

[Carl Worth <cworth@cworth.org>]

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On Thu, 10 Dec 2009 22:10:13 -0800, Dirk Hohndel <hohndel@infradead.org> wrote:
> I'm in the search results window in Emacs, on an LKML thread with 140+
> messages. I hit return to view this thread - Emacs consumes 100% CPU
> but even after waiting 3 minutes it doesn't display the result (this is
> on a fast system Lenovo x200s). 
> 
> C-g stops the process and gets me dumped into a clearly partially
> processed buffer.
> 
> Is there a good way to collect more profiling information to figure out
> why this is so slow?

My guess is that it's not a problem of being slow.

It sounds much more likely that some of our lame emacs lisp code has
gotten itself into an infinite loop.

We've got a bunch of silly, ad-hoc code for jumping around the emacs
buffer looking for various things. And then we have invisible characters
in the emacs buffer which make some of the movement commands behave
differently, and unreliably. So there's some ugliness here.

The right fix is to move more of the parsing logic into the C code where
I can actually comprehend things, and then emit some fully-quoted
structure that we can walk with simple, reliable emacs code.

In the meantime, if I could get my hands on a message that triggers this
bug, that would be useful. (Here's a case where it would be nice to have
the "notmuch search --output=maildir" command I had talked about so that
we could export the results of a particular search.)

-Carl

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