Fwd: khtml rendering performance

[Luciano Montanaro]

----------  Mensaje reenviado  ----------

Subject: khtml rendering performance
Date: Jueves 02 Diciembre 2004 18:38
From: Luciano Montanaro <mikelima at cirulla.net>
To: kfm-devel at kde.org
Cc: Gianni Trevisti <gianni.trevisti at consulenti.fastweb.it>

I am testing konqueror (well, konqueror embedded, but khtml is the same)
on a slowish set-top-box machine, and I am facing a problem that on faster
hardware is not so evident:

KHTML renders the the full page again each time some elements of it are
dynamically changed. This makes the machine crawl when, for example, a
clock as the one you can find at the link below is running in the 
background.

Firefox is much better in this regard, and it manages to repaint only what
has actually changed on the screen.

I have a test case to show the problem, which can be found at:

http://www.cirulla.net/test-clock.html

To check what is actually rendered I have, quite cruelly, used dd to 
copy /dev/zero to /dev/fb0 

Fixing this properly could vastly improve performance on highly dynamic
sites, and I may try to help, but I suspect it is not an easy problem to
address, and the fix would probably be quite invasive.

So, in the meantime, I'll have to work around this problem somehow.
Do you have any suggestions on how?

I can turn dynamically updated sections on my page in separate objects with
fixed sizes, but the change would be quite invasive, and the result would
not be particularly pretty to maintain.


--
Luciano Montanaro

Any sufficiently advanced technology is indistinguishable from a yo-yo
                                                          - Enoch Root