[MPICH] problems in achievement of effective speedup

Anna Mereu anna.mereu at diee.unica.it
Thu Jun 21 10:59:37 CDT 2007

I'm running a 5-processes application composed by one master and four 
I want to run them in in parallel on two machines: the first machine 
(machine A) has 1 processor,the second one (machine B) has four processors.
So, my intention is to run the master process in the machine A, while 
the slaves in the machine B.
I'm using the globusrun command with a specification file .rsl.
The problem is that when i run the whole application only in the machine 
A i obtain a stopping time
smaller than if i run the master in A and the slaves in B. How can it be 
I know that we obtain real benefits from parallelization if we maximize 
the parallel part of the application.
I think that my example shoul be fine to  obtain effective speedup, but 
in fact it doesn't work...
Another problem is that if i run the whole application in the 
4-processors machine it is always much slower than in the 1-processors 
So, i am very confuse about these results.....
Can somebody help me??????
Thank you in advance

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