Unique set size¶
The portion of a process’s resident memory backed by pages private to that process and therefore expected to be reclaimed if it terminates.
Core Idea¶
USS estimates nonshared physical memory by counting resident pages mapped only by one process, separating them from proportional and full resident-set measures under an operating system’s accounting interface. The kernel or profiler inspects page mappings and sharing counts, attributes uniquely mapped resident pages to the process, and sums their sizes at a sampling instant. The abstraction is therefore identified by a declared carrier, a transformation or constraint over that carrier, and an invariant that tells an analyst whether the named structure is genuinely present.
Scope of Application¶
Unique set size belongs to operating system measurement and is useful where the analyst can specify the typed operating system measurement carrier, defining objects and relations, parameters, conventions, evidence, boundary cases, and comparison targets, then evaluate process identity, page residency, mapping and copy-on-write treatment, sharing-count rule, sampling time, kernel interface, and aggregation are explicit. The scope is broad within that domain but bounded by the need for process identity, page residency, mapping and copy-on-write treatment, sharing-count rule, sampling time, kernel interface, and aggregation are explicit. The entry records a descriptive analytical identity; practical use requires the governing domain's evidence, standards, and safety obligations.
Clarity¶
The abstraction clarifies a crowded vocabulary by making process identity, page residency, mapping and copy-on-write treatment, sharing-count rule, sampling time, kernel interface, and aggregation are explicit the center of the account. A claim should name the carrier, the governing operation or relation, the applicable assumptions, and the recognition test. A bare label is insufficient because the name Unique set size can be used for a formal identity, an implementation, or a neighboring result unless carrier and convention are stated.
Manages Complexity¶
Without the abstraction, an analyst must reason directly over many local details: the carrier roles, admissibility assumptions, competing conventions, derived invariants, boundary cases, and proof or validation obligations specific to Unique set size. Unique set size compresses them into the roles in the structural signature. That compression permits comparison across instances without erasing the variables that determine validity. It also exposes which details may be varied safely and which are constitutive.
Abstract Reasoning¶
- Identify the carrier. State what the elements, states, objects, or observations are: the typed operating system measurement carrier, defining objects and relations, parameters, conventions, evidence, boundary cases, and comparison targets. Reject examples whose alleged carrier belongs to a different problem. 2. Lock the constitutive rule. Express process identity, page residency, mapping and copy-on-write treatment, sharing-count rule, sampling time, kernel interface, and aggregation are explicit independently of one notation or implementation.
Knowledge Transfer¶
Knowledge transfers strongly among subfields of operating system measurement because they reuse the typed operating system measurement carrier, defining objects and relations, parameters, conventions, evidence, boundary cases, and comparison targets, The kernel or profiler inspects page mappings and sharing counts, attributes uniquely mapped resident pages to the process, and sums their sizes at a sampling instant., and type the carrier, state every parameter and convention in the definition, test that process identity, page residency, mapping and copy-on-write treatment, sharing-count rule, sampling time, kernel interface, and aggregation are explicit, compare the nearest accepted identity, and report counterexamples, uncertainty, and limiting cases.
Relationships to Other Abstractions¶
Current abstraction Unique set size Domain-specific
Parents (1) — more general patterns this builds on
-
Unique set size is a kind of Measurement Prime
The proposed strict upward parent is
prime:measurement.
Hierarchy path (1) — routes to 1 parentless root
- Unique set size → Measurement
Neighborhood in Abstraction Space¶
Unique set size sits in a crowded region of the domain-specific corpus (29th percentile for distinctiveness): several abstractions share nearly its structure, so a description that fits it tends to fit its neighbors too.
Family — Operating Systems, Processes & Storage (18 abstractions)
Nearest neighbors
- Demand paging — 0.92
- System image — 0.92
- Process state — 0.92
- Background process — 0.91
- Virtual address space — 0.90
Computed from structural-signature embeddings · 2026-09-08