Priority scheduling in parallel I/O systems

Performance of I/O intensive applications on a multiprocessor system depends mostly on the variety of disk access delays encountered in the I/O system. With increasing processor speeds and multiprocessor organization, the demands on the I/O subsystem have been steadly growing. To obtain a better system performance it is necessary to improve the I/O performance. An event-driven parallel I/O simulator has been developed to evaluate the impact of delays in the parallel I/O system. Many I/O intensive applications have more read access than the write. We have proposed read priority I/O scheduling algorithm to such application programs. We have found 3% to 10% improvement in the I/O system performance. The results of the I/O simulator has been validated by an analytical model that we have developed. Analytical model results fairly agrees with simulator. Our results indicated that priority based I/O scheduling could be benificial to overall performance