Thanks all for the answers,
I am parallelizing tomography algorithm which takes about 5 hours using
I want to gain full performance and should reduce the computational
time as short as possible.
I was wondering the SSh/RSH launcher could be a performance
issue?(I am just guessing)
What kind of software/middleware I should use to solve the
(different launchers ,may be Sun Grid
Engine,XGrid ? ) I am runing Debian/Lenny and since the project is
academic I want to use OSS ..
Jeff Squyres wrote:
On Jun 29, 2009, at 2:19 AM, vipin kumar wrote:
Q. Since I am using TCP/Ethernet I guess
that MPI uses SSH/RSH to communicate between peers.
Ans. May be you are right. I don't know exactly how peers communicate
in MPI environment, but I can say for sure that OpenMPI uses rsh/ssh as
one of the available launchers.
Open MPI uses two different mechanisms for launching individual MPI
processes vs. MPI communications. rsh/ssh is one of the options that
Open MPI can use for launching MPI processes, but we don't keep those
channels open and don't use them for MPI communications. Individual,
new TCP sockets are opened for MPI_SEND / MPI_RECV (etc.) traffic.
These sockets are not encrypted (like ssh connections would be).
Q. And for that, each peer should have the
copy of the application right?
Ans. Absolutely correct. But If you don't want to copy binaries
manually you should use "--preload-binary" option. OpenMPI will copy
the executables in remote nodes before launching processes, and will
delete when job gets done.
It is almost always good to use latest version. "--preload-binary"
option may be absent in old versions.
It is new in the 1.3 series; it did not exist in the 1.2 series.