OPIMQ: Order Preserving IO stack for Multi-Queue Block Device

In this work, we address the issue of ensuring the storage order in the multi-queue IO stack and propose OPIMQ, an Order-Preserving IO Stack for Multi-Queue Block Devices. OPIMQ consists of four key components: Epoch Pinning, Dual-Stream Write, Order-Preserving Mapping Table Update and Sibling-aware Delayed Mapping. With Epoch Pinning, we can preserve intra-stream order dependency across different queues. With Dual-Stream Write, we can preserve the inter-stream order dependency across different threads. With Order-Preserving Mapping Table Update, FTL can update the mapping table with respect to the storage order. With Sibling-Aware Delayed Mapping, FTL can update the mapping table only when the dual-stream write satisfies the storage order in both streams. Linux IO stack with OPIMQ outperforms the vanilla Linux IO stack by 2.9×, 2.8×, and 2.9× under Filebench varmail, dbench, and sysbench, respectively. The order-preserving FTL accompanies a 1.1% performance penalty in address translation compared to legacy FTL.