Ozone (O3): An Out-of-Order Flash Memory Controller Architecture

Abstract

Ozone (O3) is a flash memory controller that increases the performance of a flash storage system by executing multiple flash operations out of order. In the O3 flash controller, data dependencies are the only ordering constraints on the execution of multiple flash operations. This allows O3 to exploit the multichip parallelism inherent in flash memory much more effectively than interleaving. The O3 controller also provides a prioritized handling of flash operations, equipping flash management software, such as the FTL (flash translation layer), with control knobs for managing flash operations of different time criticalities. Running a range of workloads on an FPGA implementation showed that the O3 flash controller achieves 3 to 100 percent more throughput than interleaving, with 46 to 88 percent lower response times.