[SunRescue] Misc. Questions about my Ultra 10

[James Lockwood]

On Mon, 4 Dec 2000, Christopher Byrne wrote:

> The way the kernel handles IO calls and what not for the SunPCI cards is
> very memory intensive, especially if you are using shared ethernet and
> shared display on the original SunPCI card. The new SunPCI-II is a lot more
> efficient, and has it's own  (reasonalby good) display and ethernet
> capabilites. Once again the lage amount of memory isn't really in use, it's
> been reserved by the kernel to act as a buffer for the SunPCI subsystems I/O
> (storage, display etc...)

I've noticed comparable system load with both cards when using identical
video subsystems (both on-card or both through X).  The onboard ethernet
port would probably make a difference.

> The third issue of windows stuttering when you move them is inherent to most
> implementations of X windows. The fact of the matter is that X really doesnt
> make good use of the low level capabilites of the hardware it runs on
> without a lot of special tweaking. For example in my Linux box I have a
> GeForce 2 256, which has it's own X server written just for that card, and
> the 2D performance is still just plain lousy. The same applies for my U170E
> with Creator.

2D performance on the Creator/Elite is, to put it simply, staggeringly
better for operations _which take a significant amount of time_.  I've
measured bitblitting at over 7x the speed of a PGX in an AXi/Elite3D setup
(120MHz UPA). 

Where X falls flat is when there are many small display operations which
cannot effectively be batched.  The modular design of X increases latency
for any individual drawing call if the results must be synchronous or
near-synchronous (such as window drawing/moving).

Sun's X server supports the acceleration features of their high end
framebuffers very well, there wouldn't be much point to designing them in
otherwise.

> run headless or in text mode most of the time, so Sun hasn't put much effort
> into X-Windows performance, unless you get a major league CAD package or
> something similar, in which case it will have special extensions or even an
> entirely new X-server to run.

The Sun OpenGL implementation, running on an Elite3D system, is nothing
short of astonishing for operations which do not involve texturing.  An
AXi/360MHz/Elite3D can keep even with an Onyx/IR for geometry and lighting
bound applications at a tiny fraction of the price.  The Elite3D is
designed to do shaded CAD very well, and I'd say it succeeds admirably. 

-James