A Parallel Virtual Machine forE cient Scheme

Programs compiled by Gambit, our Scheme compiler, achieve performance as much as twice that of the fastest available Scheme compilers. Gambit is easily ported, while retaining its high performance, through the use of a simple virtual machine (PVM). PVM allows a wide variety of machine-independent optimizations and it supports parallel computation based on the future construct. PVM conveys high-level information bidirectionally between the machine-independent front end of the compiler and the machine-dependent back end, making it easy to implement a number of common back end optimizations that are diicult to achieve for other virtual machines. PVM is similar to many real computer architectures and has an option to eeciently gather dynamic measurements of virtual machine usage. These measurements can be used in performance prediction for ports to other architectures as well as design decisions related to proposed optimizations and object representations. 1 Introduction Our primary interest is in eecient mechanisms for implementing future-based symbolic computation on currently available MIMD machines. Having already done work in this area using the Scheme language (augmented with the future mechanismm8]]13]) we are now extending our interpreter-based results into the realm of compiled Scheme code. For this purpose we undertook the implementation of a new