Understanding the characteristics of workloads is extremely important in the design of efficient computer architectures. Accurate characterization of workload behavior leads to the design of improved architectures. The characterization of applications allows one to tune the processor micro-architecture, memory hierarchy and system architecture to suit particular features in programs. Workload characterization also has a significant impact on performance evaluation. Understanding the nature of the workload and its intrinsic features can help to interpret performance measurements and simulation results. Identifying and characterizing the intrinsic properties of an application in terms of its memory access behavior, locality, control flow behavior, instruction-level parallelism, etc. can eventually lead to a program behavior model, which can be used in conjunction with a processor model to do analytical performance modeling of computer systems. In this paper, we describe the objectives of workload characterization and emphasize the importance of obtaining architecture-independent metrics for workloads. A study of memory reference locality using some generic metrics is presented as an example.

Workload characterization: motivation, goals and methodology

Compiler directed memory management policy for numerical programs

@; programming environment are both to decrease the average page fault rate and to minimize the pauses caused by clusters of page faults. We have applied program restructuring techniques to the Smalltalk-80 object memory in order to improve the locality of reference. The analysis in this paper considers the clustering of page faults over time and distinguishes between steady-state behavior and phase transitions. We compare the effectiveness of different restructuring strategies in reducing the amount of main memory needed to obtain desired levels of performance.

Paging on an object-oriented personal computer

The performance of real-storage-management algorithms in interactive systems suggests that locality of reference extends to a significant degree across users' transactions. This paper investigates this locality of reference by analyzing page-reference strings gathered from live systems. The data confirm the supposition: They suggest that reference patterns are dominated by system data references that are implied by the user's commands. Program references appear to play only a minor role. The user command sequence is an important factor in the reference behavior of an interactive session.

Analysis of page-reference strings of an interactive system

Preliminary Analysis of Page Reference Strings of an Interactive System.

This paper describes a set of measurements of the memory reference patterns of some programs. The technique used to obtain these measurements is unusually efficient. The data is presented in graphical form to allow the reader to "see" how the program uses memory. Constant use of a page and sequential access of memory are easily observed. An attempt is made to classify the programs based on their referencing behavior. From this analysis it is hoped that the reader will gain some insights as to the effectiveness of various memory management policies.

Robert S. Fabry

Papers

Program page reference patterns