Dr. Vikram Adve 2/22
Rachel E. Gagliardi-Grabau
Computer Science & Engineering Colloquium
Advanced Optimization Techniques for Data-Parallel Programming Languages
Vikram Adve
Rice University
February 22, 1999
2:30 - 3:30 p.m.
Room 3-125 EE/CS Bldg.
Abstract
Data-parallel languages aim to provide a simple, abstract, portable
programming model applicable to a wide variety of parallel systems. The
success of these languages has been hindered by the lack of sophisticated
compilers and programming tools needed to achieve performance competitive
with hand-coded parallel programs. The Rice dHPF project is aimed at
developing compiler techniques and tool principles that provide consistently
high performance for a wide class of data-parallel applications. The project
has developed a prototype compiler and programming environment for High
Performance Fortran (HPF) to demonstrate these ideas.
In this talk, I first give a brief overview of the dHPF project and then focus on two broad areas of innovation in the dHPF compiler: (1) a flexible
framework for computation partitioning, and
(2) an abstract integer set framework for program optimization and code
generation. The computation partitioning framework in dHPF is significantly
more general than that in previous compilers, enabling more aggressive
partitioning algorithms. The abstract integer-set framework enables simple,
yet general formulations of communication analysis and optimization tasks.
We have developed a number of novel optimizations made possible by the
generality of these two frameworks. Several of these optimizations cannot
be directly implemented in any other data-parallel compiler we know of.
For HPF versions of the NAS application benchmarks, the dHPF compiler achieves execution times within 0 - 21% of sophisticated hand-coded message passing
versions of the same codes. These results require only minimal modifications of the original serial form of the codes (modifying less than 6%). Some of
the new optimizations in dHPF provide orders-of-magnitude
improvements in performance, and were crucial in obtaining these results.
Post-Colloquium Reception will be held
in the EE/CS 5th Floor Lounge from 3:30 to 4:00 p.m.