Re: bad performance

[Vladimir Vukicevic <vladimir helixcode com>]

Chad Cunningham wrote:
> 
> I recently built a new machine and gnome is not running well at all. The
> mouse hangs, things are drawn incredibly slowly, mouse movents are jerky,
> etc. The machine is a Athalon 850 with 256 megs RAM and a 32 MB Matrox
> G400. I am using the latest Helix-code stuff with gnome-1.2.1 and have
> tried both englightenment and sawmill for a window manager. The same setup
> on my PII350/128/Permedia2 runs perfectly fine, and WindowMaker on my
> Athalon runs great. Any idea what the gnome problem might be?
> 

This really does not sound like a Gnome problem -- I would expect you to
have the same problems with any other environment (i.e. a std window
manager, KDE, whatever). It sounds like it could be one of three
possible things:

1 - Misconfigured X server. Run x11perf -all on both your new machine
and old machine, and compare the numbers. I'd guess that you'll get
slower numbers on your Athlon, which is NOT correct, since it is a much
faster machine with a much faster video card. Are you sure that you have
acceleration for your matrox enabled? (Such as, is the mouse pointer is
being done in hardware?) Look at X's output when it starts up, check for
any errors from the mga driver. (Run startx from a console.) Make sure
you ARE getting the mga driver, not just a non-accel svga driver.

2 - Misconfigured kernel. Are you using a non-stable kernel? In
particular, lots of the 2.3.99-preX series (notably, 6 and above) had
major memory management issues; the resulting trash could cause you to
see some of the symptoms you describe. If you aren't already, try
running 2.2.15 or .16 (I can't vouch for .16, I have not ran it myself,
but I trust Alan ;-) Check the output of 'dmesg' every once in a while
and see if anything is spewing lost interrupts, IDE resets, or whatever.

3 - Hardware issues. You could be falling prey to one of the banes of PC
hardware, namely interrupt sharing and the like. Look at
/proc/interrupts. The G400 really wants its own interrupt. You can do
this by installing it in, say, the topmost slot on your motherboard, and
starting all other cards from the bottom. It especially hates sharing
interrupts with other high-interrupt devices, like network cards. This
could also cause some of the problems you indicate. Also, do you have
the correct RAM? Athlon's are VERY picky about the kind of SDRAM you
use. (Even though it says it's the right kind, voltage, timing, etc., it
STILL might not work. I had to go through two different manufacturers
before I found one that worked. Check AMD's pages to find a list of
compatible vendors.) Having non-fully-compatible SDRAM installed could
cause some of the issues you see.

Speaking of IDE, you should check the hdparm settings for your drives
(if you're not running SCSI). While it should not cause the problems you
describe, making sure DMA is turned on, as well as multiple-sector
access and a few other goodies can greatly speed up your system and
stability.

I hope this helps!

	-- Vladimir
	-- vladimir@helixcode.com