Shared-object System Equilibria: Delay and Throughput Analysis

TL;DR

This paper introduces a novel analytical framework for shared-object systems, enabling the estimation of job delay, throughput, and blocking times by analyzing system equilibria and contention among threads.

Contribution

It presents a new perspective on analyzing shared-object systems by defining and estimating system equilibria considering delay, throughput, and blocking times.

Findings

System equilibria relate job arrival and completion rates.

Procedures for estimating delay, throughput, and blocking times are proposed.

The approach offers analytical tools comparable to experimental and simulation methods.

Abstract

We consider shared-object systems that require their threads to fulfill the system jobs by first acquiring sequentially the objects needed for the jobs and then holding on to them until the job completion. Such systems are in the core of a variety of shared-resource allocation and synchronization systems. This work opens a new perspective to study the expected job delay and throughput analytically, given the possible set of jobs that may join the system dynamically. We identify the system dependencies that cause contention among the threads as they try to acquire the job objects. We use these observations to define the shared-object system equilibria. We note that the system is in equilibrium whenever the rate in which jobs arrive at the system matches the job completion rate. These equilibria consider not only the job delay but also the job throughput, as well as the time in which each thread blocks other threads in order to complete its job. We then further study in detail the thread work cycles and, by using a graph representation of the problem, we are able to propose procedures for finding and estimating equilibria, i.e., discovering the job delay and throughput, as well as the blocking time. To the best of our knowledge, this is a new perspective, that can provide better analytical tools for the problem, in order to estimate performance measures similar to ones that can be acquired through experimentation on working systems and simulations, e.g., as job delay and throughput in (distributed) shared-object systems.