A High Precision Refresh Method to Improve The Performance of Flash Storage Devices

With the development of flash memory, its storage density has gradually increased, but its reliability has been greatly reduced. Now, flash memory relies on LDPC to solve this problem. Although LDPC (Low Density Parity Check Code) can correct data with a high error rate, it will cause a lot of delays. The refresh operation can cause the LDPC decoding delay. In the work of this article, we propose a precise refresh strategy. On the basis of high latency pages, according to the characteristics of data access frequency, we take the read-hot data in the write-cold data as our refresh target. We test the performance of the precise refresh scheme through different workloads. Compared with ordinary refresh schemes, the average response time of flash memory storage devices is reduced by 16%-49% and the lifetime of flash memory is extended.