Hybrid I/O Requests Combination for Access Conflict Minimization in SSD

• Main Authors: BO-JUN YOU, 游博鈞
• Other Authors: Jen-Wei Hsieh
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/40581587069635714668

碩士 === 國立臺灣科技大學 === 資訊工程系 === 104 === In recent year ,Solid state drives(SSDs)has been widely used as primary storage device ,the reasons including its non-volatility , lightweight , high performance , low power consumption and shock resistance. In order to improve performance, SSDs are constructed with a number of channels with each channel connecting to a number of NAND flash chips. Despite the rich parallelism of SSD has been exploited, but the utilization of flash chip is seriously low, and one of the main reasons is access conflict between requests, and then will degrade the performance of SSD. In this paper, we proposed a hybrid I/O request combination (HYC) for minimize access conflict. First, we use static request combination to solve most of the conflict between requests. Second, in order to achieve the optimization of chip access degree and minimization of access conflict, we design dynamic request combination for write request to assign its chip location to another, and then produce combine groups to access SSD in parallel. The experiments results shows that HYC can achieve the same read performance like PIQ. In the small random file compare with PIQ, HYC reduce 91% write latency and increase the write throughput and chip access degree up to 4 times, and the full chip access degree number as much as 74 times. These results show that HYC is better than PIQ to minimize access conflict and optimize the chip access degree, and achieve higher flash chip parallelism and write performance in SSD.