Alex A. Granovsky wrote:
No, not at all. Consider simulating a physical volume. Each process is assigned to some small subvolume. It updates conditions locally, but on the surface of its simulation subvolume it needs information from "nearby" processes. It cannot proceed along the surface until it has that neighboring information. Its neighbors, in turn, cannot proceed until their neighbors have reached some point. Two distant processes can be quite out of step with one another, but only by some bounded amount. At some point, a leading process has to wait for information from a laggard to propagate to it. All processes proceed together, in some loose lock-step fashion. Many applications behave in this fashion. Actually, in many applications, the synchronization is tightened in that "physics" is made to propagate faster than neighbor-by-neighbor. As the number of processes increases, the laggard might seem relatively slower in comparison, but that isn't deadlock. As the size of the cluster increases, the chances of a system component failure increase, but that also is a different matter. |
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- Re: [OMPI users] MPI_Reduce performance Terry Frankcombe
- Re: [OMPI users] MPI_Reduce performance Gabriele Fatigati
- Re: [OMPI users] MPI_Reduce performance Ashley Pittman
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- Re: [OMPI users] MPI_Reduce performance Alex A. Granovsky
- Re: [OMPI users] MPI_Reduce performance Eugene Loh
- Re: [OMPI users] MPI_Reduce performance Alex A. Granovsky
- Re: [OMPI users] MPI_Reduce performance Ashley Pittman
- Re: [OMPI users] MPI_Reduce performance jody
- Re: [OMPI users] MPI_Reduce performance Ashley Pittman
- Re: [OMPI users] MPI_Reduce performance Jeff Squyres
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- Re: [OMPI users] MPI_Reduce performance Ashley Pittman
- Re: [OMPI users] MPI_Reduce performance Richard Treumann
- Re: [OMPI users] MPI_Reduce performance Eugene Loh
- Re: [OMPI users] MPI_Reduce performance Richard Treumann