D275 - The time-stamp counter runs at a nominal gigahertz

Status: assumed Date: 2026-08-25

The guest time-stamp counter advances at a nominal one billion ticks a second and reports that frequency; process time is in microseconds.

Why: a nominal rate keeps the arithmetic exact and makes two host machines comparable, and a counter that does not advance makes every sleep look instantaneous. The hardware's real frequency is a different number, so a title deriving a frame budget from it may pace itself wrongly; both units stay assumed until a hardware probe measures them.

Rejected:

• The host's own counter frequency: differs between machines, so runs are not comparable.
• A constant counter: indistinguishable from a stopped clock.