Energy Implications of IO Interface Design Choices.

With the availability of high performance storage technology, there is extra pressure on the efficiency of IO interfaces. In addition to the popular POSIX synchronous, POSIX asynchronous, and Linux asynchronous (libaio) IO interfaces, there are two recent interfaces, spdk and io_uring, that are increasingly attracting attention with their high performance asynchronous designs. While providing high performance IO is crucial, it is also essential to do so in an energy-aware manner. In this paper, we study the energy implications of IO interface design choices and how these choices impact a system's energy consumption. Our empirical evaluation using a power meter, an ultra-low latency storage device, and various workload behaviors including single and multiple thread scenarios allow us to lay out the most energy efficient design choices, with the goal of yielding energy-aware high-performance storage stack designs.