PPT Slide
Working Set Model
- Thus, only 2 to 5% of virtual time is spent between working sets. These transitions account for 40-50% of the total page faults of the process.
- Figure 12.8 shows how the working set sizes fluctuate between the program phases.
- Resident set: set of pages that a process currently has in memory. If the resident set == working set, then page faults should be minimal. If the resident set > working set, excessive page faults will occur. If the resident set < working set the result is inefficient use of allocate page frames.
- Resident sets vary as program runs. It makes sense to make sure the working set tracks the resident set.