Abstract Asynchronous Bulk File I/O in Titanium, a High-Performance SPMD Java Dialect (CS264 Final Project, Fall 1999)

Titanium is a high-performance explicitly parallel SPMD dialect of Java. Currently, the runtime support for file I/O is limited to the classes present in Java, which have proven too inefficient to meet the demands of high-performance scientific applications which perform large amounts of file I/O. A new library is presented which adds support for asynchronous file I/O operations to enable masking I/O latency with overlapped computation. The new library also provides support for bulk (array) I/O operations, removing much of the overhead associated with the Java I/O libraries which require the programmer to read arrays a single element at a time. Experimental results are presented which compare the performance of the new library with the existing I/O libraries on a simple external merge sort, and show the performance of the new library to be vastly superior to the existing I/O facilities for this application. Titanium is a high-performance, explicitly parallel dialect of Java recently developed at UC Berkeley for programming shared-memory and distributed-memory parallel systems. Titanium incorporates the power of Split-C, a low-level SPMD language, into a high-level object-oriented programming language that frees the programmer from much of the tedium associated with writing and debugging parallel programs. Titanium is essentially