VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Thu Dec 11 2003 - 10:39:01 CST

Dear Juan,
  Displaying remotely, even on a local network, typically runs at
least 10 times slower than displaying locally. Even on the same
LAN subnet doing remote display requires all OpenGL commands to be
packaged up, sent over the wire, rendered, etc. The biggest performance
hit occurs on OpenGL commands that require network round-trips such as
state querying commands, etc. Its possible that you're seeing a bigger
remote rendering hit on 1.8.2 because there's a once-per-frame OpenGL
error check query in VMD 1.8.2 that wasn't in 1.8.1, which is probably
requiring a network round-trip. This is the only thing I can think of
that would adversely affect remote rendering performance, everything else
that was changed in VMD 1.8.2 would cause it to do _less_ OpenGL calls and
therefor run faster. If the OpenGL error check call is indeed responsible
for the remote display performance hit, I'll change the ode so that it can
be enabled or disabled dynamically with an environment variable setting or
something similar.

In any case, I'd recommend running VMD locally unless you have a strong
reason to want to run remotely. Even disabling OpenGL error checking will
not make remote display usable for any but simple molecular structures.

Thanks,
  John Stone
  vmd_at_ks.uiuc.edu

On Sat, Dec 06, 2003 at 09:16:38PM -0800, Juan Alfredo Freites wrote:
> Hello,
>
> With 1.8.1 I was able to run vmd in my linux box from my Mac with no
> particular setting other than allowing X11 forwarding. With 1.8.2
> everything is fine as long as I don't display the molecule in the graphics
> display window. If I try to display anything vmd runs very very slow.
> I have no problems running vmd 1.8.2 in the linux box itself.
>
> The issue is not that I'm running remotely because I'm talking about local
> network, and I was doing fine with 1.8.1
>
> I'm using redhat 9 on the linux side and 10.2.8 on the mac side.
>
> Thanks.
>
> --
> J. Alfredo Freites
> Department of Physics
> University of California, Irvine
> Irvine, CA 92697-4575
> (949) 824-9921 

-- 
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