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From: Simon Marshall <Simon.Marshall@esrin.esa.it>
To: XEmacs Beta <xemacs-beta@xemacs.org>
In-Reply-To: <yv9afotgnww.fsf@ynde.idt.unit.no> (message from Sudeep Kumar
	Palat on 25 Feb 1997 11:50:23 +0100)
Subject: Re: lazy lock cpu usage
Reply-To: Simon Marshall <Simon.Marshall@esrin.esa.it>

Sudeep> Start xemacs -q and load a large file, for e.g., gnus.el.  Turn on
Sudeep> font lock.  Hold down the cursor key and look at cpu usage (I used
Sudeep> top).  When the buffer has scrolled down 20%, the cpu usage by
Sudeep> XEmacs is about 14% (it keeps increasing, presumably because,
Sudeep> XEmacs is unable to process the key input at the keyboard repeat
Sudeep> rate).

Simon> So with Font Lock mode and without Lazy Lock mode has a dramatic
Simon> slowdown?

Sudeep> Slowdown in the cpu usage.  Meaning lazy lock takes more CPU
Sudeep> cycles.

No, I said *without* Lazy Lock mode.

Do you find that turning on Font Lock mode but *not* Lazy Lock mode also
causes a slowdown when you C-n?  This is what you suggest, since later on
you had suggested that it gets worse if Lazy Lock mode is also on.

The difference is important, because nothing should be happening as you
C-n when Lazy Lock mode is *not* on, other than redisplay.  If there is a
redisplay slowdown, it will of course be a factor in the (worse) slowdown
when Lazy Lock mode *is* on.

Ta, Si.

