Re: How can I predict which regions xdisp will present me for font-locking?

[John Yates <john@yates-sheets.org>]

On Mon, Mar 12, 2012 at 2:00 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> Can you give more quantitative description of the slowdown?  E.g., how
> much time does it take to move the cursor by one character or one
> line, or to insert or delete a single character?

My work machine (4 year old technology):
o Intel Core2 Duo E8400 (Wolfdale)
  - dual core, 3GHz, 6MB shared L2, no L3
  - 8GB DDr2 via separate Northbridge chip
Barely tolerable, perceptible delay inserting characters

Home machine (3 year old technology):
o AMD Phenom II x4 945
  - quad core, 3GHz, 512KB private L2, 6 MB shared L3
  - 8GB DDR2 via low latency on-chip memory controller
Really painful, at least a second to insert a single character.

Both machines run Ubuntu, the same emacs-snapshot and the same set of
init files.  My guess is that the much larger low latency Intel L2
cache is what makes the difference.

The other thing I am noticing on both machine is that when I use
keyboard repeat to "C-n" or arrow down I get scrolling behaves akin to
an iPhone: after I release my key a large number of buffered input
events continue the scrolling.

> If you replace cc-mode Lisp files in v24 with those in v23, does the
> problem go away?

I am really not able to do so.  I do not build emacs from scratch.  I
simply run the current state of Julien Danjou's emacs-snapshot on
Ubuntu (11.04 at home, 11.10 at work).

/john