Thanks Jeff
I havnt used the -s option for mpirun, the executable is residing on
all m/cs. Basically its a master slave approach wherin the master
sends chunks of data to all slaves for processing and wait for the slaves to return the partial output. This process continues untill there is no more data to send.
On Wed, 02 Jun 2004 Jeff Squyres wrote :
>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@lam-mpi.org
>{+} http://www.lam-mpi.org/
Thanks Jeff
I havnt used the -s option for mpirun, the executable is residing on
all m/cs. Basically its a master slave approach wherin the master
sends chunks of data to all slaves for processing and wait for the slaves to return the partial output. This process continues untill there is no more data to send.
On Wed, 02 Jun 2004 Jeff Squyres wrote :
>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/
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