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Subject: [OMPI users] Problem with MPI_BARRIER
From: Ghislain Lartigue (ghislain.lartigue_at_[hidden])
Date: 2011-09-08 06:20:19


Hello,

at a given point in my (Fortran90) program, I write:

===================
start_time = MPI_Wtime()
call MPI_BARRIER(...)
new_time = MPI_Wtime() - start_time
write(*,*) "barrier time =",new_time
==================

and then I run my code...

I expected that the values of "new_time" would range from 0 to Tmax (1700 in my case)
As I understand it, the first process that hits the barrier should print Tmax and the last process that hits the barrier should print 0 (or a very low value).

But this is not the case: all processes print values in the range 1400-1700!

Any explanation?

Thanks,
Ghislain.

PS:
This small code behaves perfectly in other parts of my code...