Data Recording and Monitoring for Analysis of System Response Times
J. P. Penny · The Computer Journal · 1986
A formal basis is proposed for determining what data should be recorded for monitoring to evaluate response-time performance of a time-sharing system. The proposal is made because of perceived limitations of traditional performance monitors. The essential idea is that one views requests from each user as being handled by a single, abstract, interactive process, which can be in any of a possibly large number of disjoint states. These states are defined by whether or not each interactive process is running on, or is queued for, any of a specified set of system resources. The value of the proposal is illustrated by describing the advantages and limitations of a software monitor developed to measure components of response time for interactive work on Prime Series 50 machines. After a discussion of the possibility of other implementations of the formal model, the essential requirements for such implementations are summarised.