In many real applications, for example those with frequent and irregular communication patterns or those using large messages, network contention and contention for message processing resources can be a significant part of the total execution time. This paper presents a new cost model, called LoGPC, that extends the LogP 9 and LogGP 4 models to account for the impact of network contention and network interface DMA behavior on the performance of message-passing programs.We validate LoGPC by analyzing three applications implemented with Active Messages 11, 18 on the MIT Alewife multiprocessor. Our analysis shows that network contention accounts for up to 50% of the total execution time. In addition, we show that the impact of communication locality on the communication costs is at most a factor of two on Alewife. Finally, we use the model to identify tradeoffs between synchronous and asynchronous message passing styles.
/lp/association-for-computing-machinery/logpc-modeling-network-contention-in-message-passing-programs-e6uoJHAAhb