Re: Deffering redisplay in COMINT

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 13 Jan 2013 00:14:49 -0800 (PST)
> From: Michael Mauger <mmaug@yahoo.com>
> Cc: Vitalie Spinu <spinuvit@gmail.com>, Emacs Devel <emacs-devel@gnu.org>
> 
> In each display environment I ran the tests with `truncate-lines' set to
> `t' and then with it set to`nil'. 

When it was non-nil, did you also disable auto-hscroll-mode?
Displaying an hscrolled windows disables redisplay optimizations, so
redisplay will be much slower (and it already is slow with such long
lines).

> The two obvious takeaways from this is that GUIs are slower, and
> truncate-lines set to non-nil can be painful.

That's almost trivial.

> I've been staring at numbers for the last three days so I'm getting
> a little cross-eyed.  Let me know if there is something more that
> would help you.

AFAIU, the profiles say that redisplay takes the lion's share of the
time, and the less you trigger redisplay, the faster Emacs is.  Is
that true?  If so, this, too, should be almost obvious, since
displaying long lines is notoriously slow in Emacs.

Once again, why don't you collect the text in a buffer that is not
displayed until you actually want to present it to the user?

Also, if the text is known to be 7-bit ASCII, try displaying it in a
unibyte buffer, that should be faster in Emacs 24.