A performance analysis of local synchronization

Synchronization is often necessary in parallel computing, but it can create delays whenever the receiving processor is idle, waiting for the information to arrive. This is especially true for barrier, or global, synchronization, in which every processor must synchronize with every other processor. Nonetheless, barriers are the only form of synchronization explicitly supplied in MPI and OpenMP. Many applications do not actually require global synchronization; local synchronization, in which a processor synchronizes only with those processors from which it has an incoming edge in some directed graph, is often adequate. However, the behavior of a system under local synchronization is more difficult to analyze, since processors do not start tasks at the same time. In this paper, we use combinatorial methods to show that if the synchronization graph is a directed cycle and the task times are geometrically distributed with p = 0.5, the time it takes for a processor to complete a task, inclu...

• Type: Conference
• Year: 2006
• Where: SPAA
• Authors: Julia Lipman, Quentin F. Stout
• Keywords: Constant Upper Bounds, Distributed And Parallel Computing, Local Synchronization, SPAA 2006, Synchronization