Re: Default of jit-lock-stealth-time

[Eli Zaretskii]

> From: Richard Stallman <address@hidden>
> CC: address@hidden
> Date: Thu, 01 Mar 2007 03:14:08 -0500
> 
>     My recollection is that they do annoy, but I will need to time things
>     to give more accurate information instead of hand-waving.
> 
> I don't need _more accurate_ information, just confirmation.  I would
> like you to try turning off stealth fontification and see if you are
> frequently annoyed by the need to fontify on the fly.

I mostly use very fast (3 Ghz) machines nowadays, which are not easily
forced into annoying delays.  I could try to find a slower machine,
but I need to know what is the clock speed we consider as
``reference'' for such investigations.  That is, with what slow clock
speeds we would still like Emacs to be reasonably responsive?

On a 3-GHz machine, with jit-lock-stealth-time set to nil, I measure a
consistent 5-10% increase in CPU time when paging up thru sufficiently
long Texinfo documents wrt to an already fontified buffer (18%-25%
percent the first time I page up, vs 10%-16% on subsequent attempts).
By contrast, with the default setting of jit-lock-stealth-time I see
only 1-3% of CPU being used while stealth fontification runs in the
background, which is barely distinguishable from a totally idle
machine.