Research on intercore communication of Kunpeng CPU based on MPI
Intercore communication delay is an important factor affecting the overall operation efficiency of high-performance computing systems.The domestic Kunpeng CPU is increasingly widely used in the field of high-performance computing.This pa-per analyzed the cache architecture and multi-core interface interconnection of Kunpeng CPU,and studied the factors affecting the communication delay between Kunpeng CPU cores.By conducting inter kernel communication experiments in the message passing interface(MPI)environment,comparing communication delays in different modes including cross three-level caching and cross physical CPU communication,it was found that when communication packets were greater than 500KB,the communi-cation delay across L3 Cache TAG was actually lower than that of shared L3 Cache TAG.In response to the communication de-lay anomaly of communication packets at a size of 64 KB,analysis indicated that it was caused by the default switching threshold of the Eager mode and Rendezvous mode of MPI.By comparing these two modes through experiments,it was verified that the Ea-ger mode was more suitable for sending small messages with low latency when communication packets of different sizes were in different modes and cross core communication.In practical applications,the default switching thresholds for both modes could be adjusted based on the size of communication data packets to achieve better transmission results.The experimental results indica-ted that due to the complex multi-core structure of Kunpeng CPU,targeted optimization could be carried out in parallel compu-ting program design to improve program efficiency.