Evaluating Energy-Efficiency of DRAM Channel Interleaving Schemes for Multithreaded Programs

Satoshi IMAMURA  Yuichiro YASUI  Koji INOUE  Takatsugu ONO  Hiroshi SASAKI  Katsuki FUJISAWA  

Publication
IEICE TRANSACTIONS on Information and Systems   Vol.E101-D   No.9   pp.2247-2257
Publication Date: 2018/09/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.2017EDP7296
Type of Manuscript: PAPER
Category: Computer System
Keyword: 
DRAM,  address mapping schemes,  energy efficiency,  

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Summary: 
The power consumption of server platforms has been increasing as the amount of hardware resources equipped on them is increased. Especially, the capacity of DRAM continues to grow, and it is not rare that DRAM consumes higher power than processors on modern servers. Therefore, a reduction in the DRAM energy consumption is a critical challenge to reduce the system-level energy consumption. Although it is well known that improving row buffer locality(RBL) and bank-level parallelism (BLP) is effective to reduce the DRAM energy consumption, our preliminary evaluation on a real server demonstrates that RBL is generally low across 15 multithreaded benchmarks. In this paper, we investigate the memory access patterns of these benchmarks using a simulator and observe that cache line-grained channel interleaving schemes, which are widely applied to modern servers including multiple memory channels, hurt the RBL each of the benchmarks potentially possesses. In order to address this problem, we focus on a row-grained channel interleaving scheme and compare it with three cache line-grained schemes. Our evaluation shows that it reduces the DRAM energy consumption by 16.7%, 12.3%, and 5.5% on average (up to 34.7%, 28.2%, and 12.0%) compared to the other schemes, respectively.