Subject: Re: CCL:Linux questions

From: Zsolt Zsoldos <[email-masked]>
Date: Sun, 05 Sep 1999 15:22:30 -0400

Joe M Leonard wrote:
> 
> Folks,
> 
> Are there any technical reasons for picking RedHat 6.0 vs.
> SuSE 6.2?  Or, do they basically contains the same, pretty
> much up-to-date components...?
> 
There are versions of each distribution, that contain basically
the same libraries and server code. However, I am not sure, that
RedHat 6.0 is equivalent with the 6.2 version of SuSE. I do not 
have first hand experience with SuSE, but I seem to recall, that
SuSE 6.1 was the equivalent of RedHat 6.0.

In general, many people say, that RedHat releases are frequently
more buggy than other distributions (e.g. SuSE or Caldera),
because they pick the latest (frequently still experimental
or beta) versions of every component - while others tend to
go for more established, better tested packages.
I am running RedHat 6.0 and Caldera 2.2, they both seem to be 
compatible and I did not experience stability problems either.

> Also, has anybody had any luck porting "large, significant"
> OpenGL/IRIX applications to Linux?  If so, which version(s)
> of OpenGL, combined with which graphics cards did you use?
> Was Mesa able to deliver, or did you have to purchase a "real"
> OpenGL?  I am familiar with the compute performance vis-a-vis
> IRIX boxes - what were the OpenGL/graphics performance
> comparisons?
> 
I have ported a 200K lines of code system from IRIX, which is
client/server, the server code is C++, the client UI is Java,
the 3D graphics code is again C++ (VTK based). The whole port
took about a week (mainly makefile editing, some minor C++
modifications because the egcs compiler was more strict about
ANSI compliance than the MipsPro compiler on IRIX).

For the OpenGL, I have tried 4 different systems:

1. Metro OpenGL software, 
2. Metro Extreme 3D hardware accelerated (beta version), 
3. XiG Accelerated X software OpenGL, and 
4. XiG 3D hardware accelerated OpenGL (limited availability technology demo).

Solutions 2 & 4 (hw accel) were tried on an ELSA Gloria L/MX
OpenGL accelerator graphics card (3DLabs Glint 500 MX + Delta chipset).
The software renderings were tried on the same hardware (dual
Pentium II at 350MHz 128MB RAM) as well as on a laptop (Pentium II
at 366MHz 160MB RAM). The speed of the software versions were
better than an Indy workstation, the hardware accelerated speeds
were comparable to an Indigo2 Impact graphics performance.

For precise numeric comparison, I have run the VTK speed benchmark,
for which results on various platform are available:
http://www-sop.inria.fr/caiman/personnel/Robert.Riviere/vtk/sphere-bench/

The results for the above mentioned 4 OpenGL libraries:

1. Metro software:	 69 kpolys/s
2. Metro hw.accel:	147 kpolys/s
3. XiG software:	 77 kpolys/s
4. XiG hw.accel:	145 kpolys/s

Important note, is that the hw.accel. results are greatly affected
by the size of the rendering window, because the currently available
(beta version) drivers do not support DMA - slowing down the pixel 
transfer rate substantially. On very small window, it is possible to
reach 946 kpolys/s on the same benchmark (same large number of 
geometry primitives rendered). In comparison, my Indigo2 Impact 
gives 221 kpolys/s on the same benchmark regardless of the size of 
the window. This means, once the final drivers with DMA are released
by Metro and XiG, we can expect the PC/Linux solution to beat the
SGI Impact graphics by large margin.

I do not have measurements on Mesa, but from the VTK benchmark results
page (link above) it appears that a pure Mesa on a PII 300MHz gets
a 38 kpolys/s, but on an AMD K6-III-400 Mhz with 3Dnow optimisation
it gets 74 kpolys/s. So, it seems that the XiG software is better
on a slower CPU and no 3Dnow optimisation.

Interesting to note, that the same benchmark gives an amazing
2236 kpolys/s result on the SGI Visual Workstation under NT.
With SGI's recent linux support, we can hope that they will come
out with a linux OpenGL library soon for that hardware. That
would be a real screamer beating Onyx InfiniteReality2 results!

Best regards,
Zsolt Zsoldos