+1 on what George says. In general, the only MPI collective operation that *forces* an explicit, global synchronization is MPI_Barrier. Specifically: no process can exit the barrier until all processes have entered the barrier.
In you example (MPI_Bcast), none of the non-root processes can exit the bcast before the root enters the bcast. This is a much weaker synchronization than barrier. On Nov 18, 2012, at 10:18 PM, George Bosilca wrote: > In this case the MPI_Bcast will act as a synchronization point, the slaves > will be blocked in the call until the master do the operation. > > george. > > On Nov 18, 2012, at 15:54 , Sandra Guija <sgu...@hotmail.com> wrote: > >> Hello, >> Could someone be kind and explain me the MPI_Bcast when is call by all the >> other processes? >> I am having some difficulties in fully understanding it. >> The reason I asked, it is because in my code there are some slaves calling >> the MPI_Bcast function prior the master calls it. >> Thanks, >> Sandra Guija >> >> > From: jsquy...@cisco.com >> > Date: Wed, 14 Nov 2012 08:02:13 -0700 >> > To: de...@open-mpi.org >> > Subject: [OMPI devel] topics for Dec. developer's meeting >> > >> > A few people have approached me with topics for the Dec meeting. I put the >> > ones that I could remember on the wiki. Please go fill in whatever topics >> > you want to discuss: >> > >> > https://svn.open-mpi.org/trac/ompi/wiki/Dec12Meeting >> > >> > -- >> > Jeff Squyres >> > jsquy...@cisco.com >> > For corporate legal information go to: >> > http://www.cisco.com/web/about/doing_business/legal/cri/ >> > >> > >> > _______________________________________________ >> > devel mailing list >> > de...@open-mpi.org >> > http://www.open-mpi.org/mailman/listinfo.cgi/devel >> _______________________________________________ >> devel mailing list >> de...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/devel > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
