hesela.devWorking set
In workload analysis, a working set is the set of distinct data units referenced within a specified recent observation window.
Denning defines a moving window in process execution time and a set of referenced pages; working-set size counts distinct pages, not total references. This process clock excludes periods when the process is suspended; a wall-clock window can expire references during the same pause. The set changes with the observation time and window length. [1]
For storage analysis, state the observed layer, unit identity and window rule. A host logical block, a cached translation page and a file object are different units; an entry count becomes a byte footprint only with a stated size model. This is an application of the working-set concept, not a claim about a particular SSD controller. [2]
The trace-window set is not necessarily the set currently resident in a cache. Windows uses working set for resident pageable process memory, excluding AWE and large-page allocations; that OS metric must not be substituted for a trace-window measurement. [3]
Relations
- related
- Locality of reference, Reuse distance, Miss-ratio curve, SSD mapping cache, Page cache, Cache pollution
Limitations
- A recent working set is descriptive, not a guarantee of future reuse or a complete prediction of cache hits. [1, 4]
Citations
- Peter J. Denning. The Working Set Model for Program Behavior. Communications of the ACM 11(5), May 1968, pp. 323-333, sections 2-3.
- Wang et al. LearnedFTL: A Learning-Based Page-Level FTL for Reducing Double Reads in Flash-Based SSDs. HPCA 2024, pp. 616-629, sections II-IV.
- Microsoft Learn. Working Set: resident pageable process memory and exclusions.
- Wires et al. Characterizing Storage Workloads with Counter Stacks. OSDI 2014, sections 2 and 3.2.
Further reading
Sources & caveats
- Denning section 3 supplies the process-time window definition; the storage reporting checklist is an editorial application, not an SSD experiment.
- LearnedFTL distinguishes mapping entries, translation pages and requested data. Microsoft documents the separate Windows residency meaning.
- No publication date is represented as an invention date. No new benchmark or cache-policy implementation.