From: Axel Kohlmeyer (akohlmey_at_cmm.chem.upenn.edu)
Date: Thu Jul 23 2009 - 10:02:45 CDT
On Thu, 2009-07-23 at 10:11 -0400, Sadhu, Shubho (NIH/NCI) [F] wrote:
> You could also use the +devices flag to specify certain GPU board(s)
> (you can find the numbers of the boards with the deviceQuery program
> in the Cuda SDK). I've found that if NAMD is using the same video card
> as the GUI, NAMD runs much slower. Use "grep binding <NAMD log file>"
this is an important point. particularly using the composite extension
and other x applications that cause many redraw events can cut the
performance of the GPU easily in half or worse. i found that vncviewer
is a very problematic application. in general it is good advice to
run everything but short tests on dedicated compute GPUs.
> to see which GPUs NAMD is running on. These lines are printed during
> startup. Hope this helps,
> From: owner-namd-l_at_ks.uiuc.edu [owner-namd-l_at_ks.uiuc.edu] On Behalf Of David Chalmers [david.chalmers_at_vcp.monash.edu.au]
> Sent: Thursday, July 23, 2009 8:20 AM
> To: namd-l_at_ks.uiuc.edu
> Subject: namd-l: NAMD CUDA on dual Nvidia 295 GPUs
> Dear All,
> We are trying out the CUDA version of NAMD (2.7b1 CVS version from a few
> days ago) on a machine with a quad core i7 cpu and two Geforce 295 GPUs. We
> are using Suse 11.1 with the most recent NVIDIA drivers and cuda toolkit
> We are seeing a speed-up in NAMD running on a single core, but as far as we
> can tell, the speed up is only consistent with a single GPU being used.
> When we use the 'nvidia-settings' gui, the temperature of only one of the
> four GPUs is rising much.
> This leads me to a few questions:
> Can I use all four GPUs?
> Should I be using one, four (or some other number) of cores?
> Which version of NAMD should I be using, multicore or the charmrun version?
> Is there some way that I can better understand how many GPUs NAMD is using?
> Thanks for any advice,
> David Chalmers
> Faculty of Pharmacy, Monash University
> 381 Royal Pde, Parkville, Vic 3053. Australia
-- ======================================================================= Axel Kohlmeyer akohlmey_at_cmm.chem.upenn.edu http://www.cmm.upenn.edu Center for Molecular Modeling -- University of Pennsylvania Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323 tel: 1-215-898-1582, fax: 1-215-573-6233, office-tel: 1-215-898-5425 ======================================================================= If you make something idiot-proof, the universe creates a better idiot.
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