Maximizing IO Performance Via Conflict Reduction for Flash Memory Storage Systems
Qiao Li1,a, Liang Shi1,b, Congming Gao1,c, Kaijie Wu1,d, Chun Jason Xue2,
Qingfeng Zhuge1,e and Edwin H.-M. Sha1,f
1College of Computer Science, Chongqing University, Chongqing, China.
2Department of Computer Science, City University of Hong Kong, Kowloon, Hong Kong.
Flash memory has been widely deployed during the recent years with the improvement of bit density and technology scaling. However, a significant performance degradation is also introduced with the development trend. The latency of IO requests on flash memory storage systems is composed of access conflict latency, data transfer latency, flash chip access latency and ECC encoding/decoding latency. Studies show that the access conflict latency, which is mainly induced by the slow transfer latency and access latency, has become the dominate part of the IO latency, especially for IO intensive applications. This paper proposes to reduce the flash access conflict latency through the reduction of the transfer and flash access latencies. A latency model is built to construct the relationship among the transfer latency and access latency based on the reliability characteristics of flash memory. Simulation experiments show that the proposed approach achieves significant performance improvement.
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