Title :
A performance comparison of DRAM memory system optimizations for SMT processors
Author :
Zhu, Zhichun ; Zhang, Zhao
Author_Institution :
Dept. of Electr. & Comput. Eng., Illinois Univ., Chicago, IL, USA
Abstract :
Memory system optimizations have been well studied on single-threaded systems; however, the wide use of simultaneous multithreading (SMT) techniques raises questions over their effectiveness in the new context. In this study, we thoroughly evaluate contemporary multi-channel DDR SDRAM and Rambus DRAM systems in SMT systems, and search for new thread-aware DRAM optimization techniques. Our major findings are: (1) in general, increasing the number of threads tends to increase the memory concurrency and thus the pressure on DRAM systems, but some exceptions do exist; (2) the application performance is sensitive to memory channel organizations, e.g. independent channels may outperform ganged organizations by up to 90%; (3) the DRAM latency reduction through improving row buffer hit rates becomes less effective due to the increased bank contentions; and (4) thread-aware DRAM access scheduling schemes may improve performance by up to 30% on workload mixes of memory-intensive applications. In short, the use of SMT techniques has somewhat changed the context of DRAM optimizations but does not make them obsolete.
Keywords :
DRAM chips; buffer storage; multi-threading; optimisation; performance evaluation; scheduling; DRAM latency reduction; DRAM memory system optimizations; Rambus DRAM systems; SMT processors; SMT systems; independent channels; memory channel organization; memory concurrency; multichannel DDR SDRAM; row buffer hit rates; simultaneous multithreading; single-threaded systems; thread-aware DRAM access scheduling; thread-aware DRAM optimization; Concurrent computing; DRAM chips; Delay; Design optimization; Employment; Multithreading; Parallel processing; Random access memory; Surface-mount technology; Yarn;
Conference_Titel :
High-Performance Computer Architecture, 2005. HPCA-11. 11th International Symposium on
Print_ISBN :
0-7695-2275-0
DOI :
10.1109/HPCA.2005.2