Re: Display slowness that is painful

[Evil Boris]

Richard Stallman <address@hidden> writes:

> I just displayed a large binary buffer which had many chars in the range
> 0200 to 0377.  And the region was large, too.  This led to a very long loop
> in which I saw the following on the stack
>
>     try_scrolling, Fwindow_end,
>     start_display...get_next_display_element...handle_stop...handle_face_prop,
>     face_at_buffer_position, merge_named_face (on Qregion)
>
[...]
> I can make the test case available if necessary.
> It is a 1.3 meg GIF file.

I seem to have run into a similar problem.  In my case, it's an .EPS
file produced by Adobe Photoshop (about 200kb), full of characters in
that range too (some sort of binary data, plus maybe a preview).
Turning font-lock off does not help.  Switching to fundamental-mode
does not help.  Symptoms: The file takes a long time to load.
Executing M-> took 10-5 mins (!!!) on my machine.  Cursor motions w/o
scrolling when none of the funny characters are visible is near
instantaneous.  When some of the characters are visible on the top of
the screen (top one line), moving the cursor up and down takes a
second or two.  Doing large motions with much of the screen occupied
by funny characters sends Emacs into CPU-time eating look. 100% CPU
utilization for minutes at a time.  First time I ran into this I
thought Emacs hung altogether.

Not sure if it helps.  What else can I check?  I would rather not send
the file, though.

    --Boris