A Data Streams Speculation Technique for Shared-Memory Multi-core DSPs

Multi-Core Digital Signal Processors (MC-DSPs) often suffer from limited memory bandwidth and long access latency caused by shared-memory structures. Data forwarding is an efficient data speculation technique to hide memory access latencies. This paper proposes a new Data Stream Clustered Forwarding (DSCF) technique for MC-DSPs in shared-memory structures. DSCF combines data streams forwarding operations triggered by specific forwarding primitives with a background transmission controlled by customized control units. DSCF is based on normal cache coherency protocols and has lower hardware overhead, no pollutions to destination DSP caches and good system scalability. The simulation results show that, DSCF can reduce the cache coherency miss ratio of our MC-DSP prototype by 47% on average, get 1.41 performance speedup ratio compared with the original structure without data speculation, and improve the system performance by about 12% compared with the related data forwarding technique.