Analyzing the I/O behavior of supercomputer applications

The authors describe the collection and analysis of supercomputer I/O (input/output) traces on a Cray Y-MP. Analyzing these traces, which came primarily from programs with high I/O requirements, shows the file system I/O patterns that these applications exhibit. The authors classify application I/Os into three categories, required, checkpoint, and data staging, and show how memory size and CPU speed are likely to affect each category. An analysis of the data shows that data staging I/O dominates when it is present.<>