Work-in-Progress: PreGC: Pre-migrating Valid Pages to Relieve Performance Cliff of 3D Solid-State Drives

Abstract

In order to satisfy the increased concern on SSD performance, this paper studied GC performance in the view of performance cliff and tail latency. At first, our preliminary experiments figure out that increased page migrations is the root cause of performance cliff. Then, combined with the existing works aiming at GC performance in 2D SSDs, including the partial GC and aggressive GC, a novel GC-assisting method PreGC is proposed to relieve GC-induced performance cliff. The key idea of PreGC is that a part of pages within victim blocks can be pre-migrated ahead of the time nearby GC invoking and when system is idle. Thus, normal page migrations induced by GC can be reduced and response time peaks would be lowered down. Experimental results show that PreGC can efficiently relieve the performance cliff by reducing migrated page numbers in normal GC as well as the tail latency while inducing negligible write amplification.