@MastersThesis{subramaniam:msthesis, author = {Mahesh Subramaniam}, title = {Efficient Implementation of Server-Directed I/O}, year = {1996}, month = {June}, school = {Dept. of Computer Science, University of Illinois}, URL = {http://bunny.cs.uiuc.edu/CDR/pubs/mahesh-thesis.html}, keywords = {parallel I/O, multiprocessor file system, pario-bib}, abstract = {Parallel computers are a cost effective approach to providing significant computational resources to a broad range of scientific and engineering applications. Due to the relatively lower performance of the I/O subsystems on these machines and due to the significant I/O requirements of these applications, the I/O performance can become a major bottleneck. Optimizing the I/O phase of these applications poses a significant challenge. A large number of these scientific and engineering applications perform simple operations on multidimensional arrays and providing an easy and efficient mechanism for implementing these operations is important. The Panda array I/O library provides simple high level interfaces to specify collective I/O operations on multidimensional arrays in a distributed memory single-program multiple-data (SPMD) environment. The high level information provided by the user through these interfaces allows the Panda array I/O library to produce an efficient implementation of the collective I/O request. The use of these high level interfaces also increases the portability of the application. \par This thesis presents an efficient and portable implementation of the Panda array I/O library. In this implementation, standard software components are used to build the I/O library to aid its portability. The implementation also provides a simple, flexible framework for the implementation and integration of the various collective I/O strategies. The server directed I/O and the reduced messages server directed I/O algorithms are implemented in the Panda array I/O library. This implementation supports the sharing of the I/O servers between multiple applications by extending the collective I/O strategies. Also, the implementation supports the use of part time I/O nodes where certain designated compute nodes act as the I/O servers during the I/O phase of the application. The performance of this implementation of the Panda array I/O library is measured on the IBM SP2 and the performance results show that for read and write operations, the collective I/O strategies used by the Panda array I/O library achieve throughputs close to the maximum throughputs provided by the underlying file system on each I/O node of the IBM SP2.} }