[Beowulf] GPU diagnostics?

[David Mathog]

M.J. Harvey kindly supplied

> http://ccs.chem.ucl.ac.uk/~matt/cudamemtest.tgz

I built this last night on a Mythbuntu 8.10 system with an 8400 GS card,
and Nvidia driver 180.41.  Used the cuda 2.1 toolkit for Ubuntu 8.04
(seemed like the closest match).  There were a few warnings at compilation.

  export LD_LIBRARY_PATH=/usr/local/cuda/lib
  ./memtest

seemed to start ok, putting up a bunch of reasonable looking information
about the graphics card, then it gets down to a "bit test" line, then
sits there for a very long time.  CPU usage is at 100%. There are no
periodic status messages.  Eventually the screen goes blank and it
stops.  This isn't the normal screen blanking, the screen is wiped
clean, but hitting a return pulls up the prompt.  This was running as
root in single user console mode (no X11). Oddly, output even though
this was running in bash, output could not be redirected with

 ./memtest 2>&1 | tee mytest.log

When run that way, nothing showed up in either the file or on the
screen.  memtest allocated 222 MB (if memory serves) out of the 256MB on
the card.

Anyway, I seem to be doing something wrong.  Does this code need to be
run in an ssh with the monitor not attached? Maybe driver 180.41 is not
fully cuda capable?  Why won't the output redirect?

Thanks,

David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech