Application of the Page Survival Index (PSI) to Virtual-memory System Performance

The Page Survival Index (PSI) was defined in a preceding paper where it was used to describe the behavior of individual programs running in a time sharing environment. Here we show how a system-wide value of PSI can be calculated on the fly by the operating system. This value can be used to estimate users’ memory requirements and to control system performance by maintaining the proper multiprogramming level. Simulation results show that a scheduler based on these concepts can achieve significant improvements in system performance.