Patent ID: 8453003
Filing Date: 2013-05-28
Classification: G06F

Abstract:
1. A communication method in a parallel computer comprising: a plurality of processors; an inter-processor network connected to said plurality processors; and an inter-processor synchronization control section configured to establish inter-processor synchronization among said plurality of processors, said communication method comprising: said inter-processor synchronization control section executing the inter-processor synchronization to overlap with a previous process before a collective communication phase, in which communications are performed at a same time among said plurality of processors through said inter-processor network, or a communication of a partial communication phase during a time period required for the inter-processor synchronization, said communication method further comprising: (1a) each of said plurality of processors starting the previous process before entering the collective communication phase; (1b) said each processor executing a synchronization command in advance at a time when a portion of the previous process for a predetermined time period t (1c) said each processor sending a synchronization request to said inter-processor synchronization control section in the execution of the synchronization command; (1d) said each processor receiving a synchronization completion notice; (1e) said each processor executing the previous process in parallel with said (1b) to (1d); and (1f) after said (1e), said plurality of processors entering the collective communication phase after confirmation of reception of the synchronization completion notices, wherein said inter-processor synchronization control section executing the inter-processor synchronization comprises: (1g) said inter-processor synchronization control section receiving the synchronization, requests from all of said processors; and (1h) said inter-processor synchronization control section transmitting the synchronization completion notice to said each processor, if the synchronization request is received from said each processor and a synchronization condition is met, the communication method further comprises: (2a) entering the collective communication phase which is divided into a plurality of partial communication phases; (2b) entering one of said plurality of partial communication phases; (2c) said each processor starting a partial communication with another of said plurality of processors; (2d) said each processor executing the synchronization command in advance in a state that a portion of said partial communication for a predetermined time period t (2e) said each processor sending out the synchronization request to said inter-processor synchronization control section in the execution of the synchronization command; (2f) said inter-processor synchronization control section receiving the synchronization request from said each processor; (2g) said inter-processor synchronization control section transmitting the synchronization completion notice to said each processor when the synchronization requests are received from all of said plurality of processors and the synchronization condition is met; (2h) said each processor receiving the synchronization completion notice; (2i) said each processor continuing the partial communication in parallel to said (2d) to (2h); and (2j) after said (2i), said plurality of processors entering a next one of said plurality of partial communication phases after confirmation of reception of the synchronization completion notices.