Loop scheduling optimization for chip-multiprocessors with non-volatile main memory

Abstract

Non-Volatile Memories (NVMs) have many advantages over traditional DRAM. It is desirable to apply NVM as main memory in embedded Chip Multi-Processor (CMP) systems. However, NVMs have drawbacks that need to be overcome. That is, a write to the NVMs is expensive. Loops are the most critical and time-consuming part in digital signal processing (DSP) applications. However, loops are difficult to parallelize on multi-processor systems due to the inter-iteration dependencies. This paper targets on embedded CMP systems and proposes techniques to improve loop parallelism while considering reducing the write activities to the NVMs when they are used as main memory. The experimental results show that the proposed algorithm can reduce the number of write activities on NVM by 21.1% on average. In other words, the average lifetime of NVM can be extended to at least 2 times longer than before and the total schedule length is reduced by 19.6% on average.