Compiler and runtime support for running OpenMP programs on Pentium- and Itanium-architectures

Exploiting thread-level parallelism (TLP) is a promising way to improve the performance of applications with the advent of general-purpose cost effective uni-processor and shared-memory multiprocessor systems. In this paper, we describe the OpenMP implementation in the Intel® C++ and Fortran compilers for Intel platforms. We present our major design consideration and decisions in the Intel compiler for generating efficient multithreaded codes guided by OpenMP directives and pragmas. We describe several transformation phases in the compiler for the OpenMP parallelization. In addition to compiler support, the OpenMP runtime library is a critical part of the Intel compiler. We present runtime techniques developed in the Intel OpenMP runtime library for exploiting thread-level parallelism as well as integrating the OpenMP support with other forms of threading termed as sibling parallelism. The performance results of a set of benchmarks show good speedups over the well-optimized serial code performance on Intel® Pentium- and Itanium-processor based systems.