NPAC Technical Report SCCS-487
Issues in Software Support for Parallel I/O
Rajesh Bordawekar
Submitted May 01 1993
Abstract
This thesis looks at various issues in providing application-level
software support for parallel I/O. We show that the performance
of the parallel I/O system varies greatly as a function of data
distributions.
We present runtime I/O primitives for parallel languages which allow
the user to obtain a consistent performance over a wide range of data
distributions.
In order to design these primitives, we study various parameters
used in the design of a parallel file system. We evaluate the
performance of Touchstone Delta Concurrent File System and study the
effect of parameters like number of processors, number of disks, file
size on the system performance. We compute the I/O costs for common
data distributions. We propose an alternative strategy -two phase data
access strategy- to optimize the I/O costs connected with
data distributions. We implement runtime primitives using the
two-phase access strategy and show that using these primitives not
only I/O access rates are improved but also user can obtain complex
data distributions like block-block and block-cyclic.