V Input / Output Behavior of Supercomputing Applications

Tits paper describes the collection and analysis of supercomputer I/O traces and their use in a collection of buffering and caching simulations. TJ,As serves two purposes. First, it gives a model of how individual applications running on supercomputers request f'fl¢ system I/0, allowing system designers to optimize I/0 hardware and file system algorithms to that model. Second, the buffering simulations show what resources are needed to maximize the CPU utilization of a supercomputer given a very bursty I/0 request rate. By using read-ahead and write-behind in a large solid-state disk, one or two applications were sufficient to fully utilize a Cray Y-MP CPU.