On Tue, 1 Jun 2004, mohammed mubeen jukaku wrote:
> I have developed a parallel MP3 encoder using BladeEncoder as the base.
> It runs quite fast on NFS (I have a single home dir). But its damm slow
> when not on NFS (for eg. when i run from /tmp, which is availble on all
> m/cs) - ofcourse slower than the serial encoder. Can any1 help me?
While your results may seem counter-intuitive, there are probably a lot of
factors involved here. One large one to investigate is how you're sending
the data out. Another is how you're sending the executable out (are you
using the -s option to mpirun, or is the executable and/or data already
staged on each node).
You might want to throw some crude timers around portions of your program
and see exactly where the delay is occuring -- sometimes such timers and a
binary search through your code (narrowing the timer range on smaller and
smaller parts of your code to find out where the major time sink is) can
be quite enlightening. :-)
--
{+} Jeff Squyres
{+} jsquyres_at_[hidden]
{+} http://www.lam-mpi.org/
|
