The aggregate server method for analyzing serialization delays in computer systems
Subhash C. Agrawal, Jeffrey P. Buzen · ACM Transactions on Computer Systems · 1983
Method for Analyzing Computer SystemsThe aggregate server method is an approximate, iterative technique for analyzing the delays that programs encounter while waiting to enter critical sections, non-reentrant subroutines, and similar software structures that cause processing to become serialized.The method employs a conventional product form queuing network comprised of servers that represent actual I/O devices and processors, plus additional aggregate servers that represent serialized processing activity.The parameters of the product form network are adjusted iteratively to account for contention among serialized and nonserialized customers at each physical device.The algorithm is developed for single-class closed queuing networks with load-independent servers employing processor sharing scheduling disciplines.Validations based on comparisons with exact numerical solutions are presented, and some factors affecting the accuracy of the method are discussed.Extensions to multiclass queuing networks, variable rate servers, and other scheduling disciplines are also suggested.