VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Mon Oct 08 2001 - 10:11:18 CDT

Dear Robert,
  Last Friday and this weekend Justin looked more closely at the CPU
usage issue you had reported, and it turns out that there was actually
a bug in the code. It only showed up on certain platforms,
apparently related to the efficiency of the graphics driver software or
something similar. The problem was not apparent on Sun machines or on
Windows as you mentioned, but was quite obvious when run on one of the
Linux machines here. The problem is now fixed, and the next version of
VMD will no longer exhibit the problem you described, on any platform.

Thanks again,
  John Stone
  vmd_at_ks.uiuc.edu

On Sat, Oct 06, 2001 at 08:57:14PM -0700, R. M. Fesinmeyer wrote:
>
> John,
>
> Thank you for your responses regarding VMD and multithreading. I will look
> for the information on transforming molecule coordinates you mentioned as
> well.
>
> With respect to graphics issues (see below), my system uses a GeForce2MX
> card with RedHat 7.1 (XFree86 upgraded to 4.0.3). I've installed the latest
> nVidia drivers and my impression is that hardware acceleration is being
> used. I don't see this behavior when running VMD on a Windows 2000 machine
> with similar hardware. I have noticed that the Windows platform provides
> better graphic performance, perhaps suggesting that hardware acceleration is
> not in use under Linux. Any insights into this issue would be appreciated.
>
> Robert
>
> > > 3) I've noticed that after creating some user defined graphic (say: draw
> > > sphere {0 0 0} radius 10), VMD goes to 100% cpu usage, even though
> > > nothing is being done interactively. Removing the graphic
> > > (Molecule-->Delete) brings VMD back to a normal "resting" cpu usage.
> > > While this isn't a problem with a single sphere, something more complex
> > > (like the Dial script) slows the system down significantly. Is this a
> > > bug, or is there a reason for this?
> >
> > Interesting: What graphics card do you use? I don't experience that
> > problem when running here on a Sun machine with an Elite3Dm6 graphics
> > board. I don't recall that behavior on a GeForce3-equipped Linux
> machine
> > either. If you're running a software-only renderer however, or a board
> > that lacks some OpenGL functionality, I could imagine this occuring.
> > Tell me more about your system and we'll figure that out.
> 

-- 
NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
Email: johns_at_ks.uiuc.edu                 Phone: 217-244-3349              
  WWW: http://www.ks.uiuc.edu/~johns/      Fax: 217-244-6078