Im new in MPI and in my lab using Rock cluster 10 nodes each has 2
processors, using mpich 1.2.7p1 in
my Linux platform,
I compute the execution time by running MPI_Wtime at begining and end of
program then subtract them.
I run the sequential code on the master machine by $./sequntial
the execution time is almost constant from 0.000771 seconds to 0.000789
I m using two processors for my parallel
When I run parallel code by $ /opt/mpich/gnu/bin/mpirun -nolocal -np 2
-machinefiles machines ./parallel
the output:
--------------------------------
Processor 0 on compute-0-0
Processpr 1 on compute-0-0
Execution Time is 0.000503 seconds
-------------------------------
This result is acceptable,
but when i run again $ /opt/mpich/gnu/bin/mpirun -nolocal -np 2
-machinefiles machines ./parallel
the execution time is 0.00129, next run 0.00288,next run 0.000666,next run
0.00199 seconds
Why the parallel execution time goes up and down, even sometimes is slower
than sequential process?.
Is it shared memory issue?
Thank for help in advance
A friend in need Is a friend indeed
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