Resource Control for Synchronous Cooperative Threads

TL;DR

This paper introduces static analysis methods to bound resource usage in synchronous cooperative threads, ensuring instant termination and polynomial resource bounds, with a virtual machine implementation for precise resource estimation.

Contribution

It develops compositional static analyses for resource bounds in synchronous threads and introduces a virtual machine with bytecode for precise resource control.

Findings

Guaranteed instant termination of systems

Polynomial bounds on resource usage

A virtual machine for resource estimation

Abstract

We develop new methods to statically bound the resources needed for the execution of systems of concurrent, interactive threads. Our study is concerned with a \emph{synchronous} model of interaction based on cooperative threads whose execution proceeds in synchronous rounds called instants. Our contribution is a system of compositional static analyses to guarantee that each instant terminates and to bound the size of the values computed by the system as a function of the size of its parameters at the beginning of the instant. Our method generalises an approach designed for first-order functional languages that relies on a combination of standard termination techniques for term rewriting systems and an analysis of the size of the computed values based on the notion of quasi-interpretation. We show that these two methods can be combined to obtain an explicit polynomial bound on the resources needed for the execution of the system during an instant. As a second contribution, we introduce a virtual machine and a related bytecode thus producing a precise description of the resources needed for the execution of a system. In this context, we present a suitable control flow analysis that allows to formulte the static analyses for resource control at byte code level.