[vtkusers] VTK performance with GeForce2 (RedHat 7.1 with NVidia drivers)

[Dave Reed]

I recently installed RedHat 7.1 with XFree 4.0.3 and thought that now
it would be worthwhile to get a new video card since XFree 4.x
provides better support for using graphics card hardware.

I have a NVidia TNT2 card and downloaded the latest OpenGL and kernel
files (.tar.gz) from NVidia's web site and did a "make install" (which
deletes the Mesa libraries), modified the XFree86 config file to use
the nvidia driver, include the correct modules, etc. as specified in
their README file, and restarted X.  I then compiled VTK 3.2 using
--with-opengl.  I checked that the kernel driver was installed and
using NVidia's libGL.

I "measured" the performance by counting the number of frames I got in
15 seconds when rotating a scene (I used the medical1 example). I then
borrowed a GeForce2 card and did the same. The GeForce2 card only
produce about twice as many frames in the same time frame. I was
expecting a much more significant improvement. I know VTK is not
optimized for use with PC graphics hardware, but I still expected more
of a difference. VTK is much faster on my Sun Elite3D at work so I
expected a reasonable improvement from the GeForce2 compared to the
TNT2 card.

One thing I did notice is the following with both the TNT2 card and
GeForce2 card:

cat /proc/nv/card0 
----- Driver Info ----- 
NVRM Version: 1.0-769
------ Card Info ------
Model:        Riva TNT2
IRQ:          11
------ AGP Info -------
AGP status:   Disabled
AGP Driver:
Bridge:       Generic Via
SBA:          Supported [disabled]
FW:           Unsupported [disabled]
Rates:        4x 2x 1x  [-]
Registers:    0x1f000207:0x00000000


I would think (obviously) that AGP status should be enabled to get the
best performance.  I've got it enabled in the XFree config file and
the log file shows it enabled and then later in the log file it is
disabled so I'm wondering if that's the problem.

Can anyone confirm that I should get a more significant improvement
with the GeForce2 card?  And also, if anyone has any suggestions for
getting AGP support enabled, I'd appreciate them.  I'll ask on a Linux
mailing list, but I thought someone here might have had the same
problem and solved it. I'm wondering if the NVidia's kernel driver
isn't set up for the changes in the Linux 2.4 kernel. I found some
old messages that it wasn't setup for the 2.3.x development kernel but
they would have a fix so I would think it would be ready by now.

Thanks,
Dave