Performance Evaluation Review

Preprint Queue

The following contributions will appear in the March 2012 issue of PER:

Title: Special Issue on The Seventh International Conference on Matrix-Analytic Methods in Stochastic Models (MAM7)
Editors: G. Latouche, V. Ramaswami, M.S. Squillante.
Type: Special Issue

Title: Special Issue on Modeling Dynamic Behaviors of Complex Distributed Systems
Editors: S. Distefano, A. Puliafito, K.S. Trivedi.
Type: Special Issue

Title: Sharp utilization thresholds for some real-time scheduling problems
Author: S. Gopalakrishnan (University of British Columbia, Canada).
Type: Regular contribution
Abstract
Scheduling policies for real-time systems exhibit threshold behavior that is related to the utilization of the task set they schedule, and in some cases this threshold is sharp. A task set is considered schedulable if it can be scheduled to meet all associated deadlines. A schedulability test for a chosen policy is a test of feasibility: given a task set, can all deadlines be met? For the rate monotonic scheduling policy, we show that periodic workload with utilization less than a threshold URM* can be scheduled almost surely and that all workload with utilization greater than URM* is almost surely not schedulable. We study such sharp threshold behavior in the context of processor scheduling using static task priorities, not only for periodic real-time tasks but for aperiodic real-time tasks as well. The notion of a utilization threshold provides a simple schedulability test for most real-time applications. These results improve our understanding of scheduling policies and provide an interesting characterization of the typical behavior of policies. The threshold is sharp (small deviations around the threshold cause schedulability, as a property, to appear or disappear) for most policies; this is a happy consequence that can be used to address the limitations of existing utilization-based tests for schedulability. We demonstrate the use of such an approach for balancing power consumption with the need to meet deadlines in web servers.

Title: An Empirical Comparison of Java Remote Communication Primitives for Intra-Node Data Transmission
Authors: P.F. Burdette (Allegheny College, US), W.F. Jones (Allegheny College, US), B.C. Blose (Allegheny College, US), G.M. Kapfhammer (Allegheny College, US).
Type: Regular contribution
Abstract
This paper presents a benchmarking suite that measures the performance of using sockets and eXtensible Markup Language remote procedure calls (XML-RPC) to exchange intra-node messages between Java virtual machines (JVMs). The paper also reports on an empirical study comparing sockets and XML-RPC with response time measurements from timers that use both operating system tools and Java language instrumentation. By leveraging packet filters inside the GNU/Linux kernel, the benchmark suite also calculates network resource consumption. Moreover, the framework interprets the response time results in light of memory subsystem metrics characterizing the behavior of the JVM. The empirical findings indicate that sockets perform better when transmitting small to very large objects, while XML-RPC exhibits lower response time than sockets with extremely large bulk data transfers. The experiments reveal trade-offs in performance and thus represent the first step towards determining if Java remote communication primitives can support the efficient exchange of intra-node messages.