VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Thu Sep 02 2004 - 12:37:07 CDT

Shirley,
  If your machine is consuming 87MB of swap before running VMD and you've
only got 512MB, it's likely that all of the disk I/O that movie making
requires is thrashing your buffer cache, and so that's the reason your
machine is sluggish. If you had more memory (say 1GB or more) you'd find
that it would run much more smoothly. This is undoubtably the reason that
the machine is still "sluggish" even after the movie generation is over
and you exit VMD. I always recommend people to get as much RAM as possible
when planning machines for use in making movies, loading large trajectories,
etc..

  John Stone
  vmd_at_ks.uiuc.edu

On Thu, Sep 02, 2004 at 08:04:33AM -0700, Shirley Li wrote:
> Hi John,
>
> Thanks a lot for your prompt response.
>
> I just restarted the linux computer, and the total/used memories are 513232/206116, and the /total/used/free SWAP usage are /1044216/87396/956820. After I load the VMD program, I checked the memory usage again, and the output is 513232/410324. The total/used/free SWAP size are /1044216/87344/956872. During the creation of animation using VMD, one step called "Encodling" takes a long time . One more thing: even after the movie creation is completed, the computer still runs more slowly than before when VMD is not loaded. Does it mean that this program requires large memory, or the memory on my linux computer is not enough?
>
> Your help will be greatly appreciated.
>
> With best regards,
>
> Shirley
>
>
>
> John Stone <johns_at_ks.uiuc.edu> wrote:
>
> Hi,
> When you saw those total/used/free values, what was your swap size?
> I.e. what does 'top' give for memory usage stats when the machine
> is unresponsive as you're describing. It is quite possible that the
> "free" memory is only due to large amounts of swap being used... :)
>
> John Stone
> vmd_at_ks.uiuc.edu
>
> --
> 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
>
>
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-- 
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