Reading from External Memory

Abstract: Modern external memory is represented by several device classes. At present, HDD, SATA SSD and NVMe SSD are widely used. Recently ultra-low latency SSD such as Intel Optane became available on the market. Each of these types exhibits it's own pattern for throughput, latency and parallelism. To achieve the highest performance one has to pick an appropriate I/O interface provided by the operating system. In this work we present a detailed overview and evaluation of modern storage reading performance with regard to available Linux synchronous and asynchronous interfaces. While throughout this work we aim for the highest throughput we also measure latency and CPU usage. We provide this report in hope the detailed results could be interesting to both researchers and practitioners.