IOAgent: Leveraging the Application Analysis of Workload Effects

Abstract — The importance of a well tuned I/O subsystem is beyond doubt. In many cases, I/O may be the real bottleneck of an application and understanding its limitations and capabilities may be of interest both from a research and from a development point of view. In this paper we propose IOAgent, a public domain tool to gen-erate synthetic workloads for the evaluation of I/O subsystems. Our tool generates multiple number of threads that may access the I/O subsystem in a variety of different ways allowing for a thorough evaluation. Our tool can also be applied to emulate the I/O of complex applications in order to analyse the impact of different parameters in the performance. In order to show the use of IOAgent we evaluate the I/O subsystem on two servers with different storage configurations. The study allows us to conclude that all different unbuffered I/O implementations in Linux show a similar performance. Also, we show that there are little performance differences among different file systems. Moreover, we test the new native kernel asynchronous I/O interface of Linux and the experiments show it has a similar performance to the synchronous one. I