A logically partitions computer system maintains a respective window for each of multiple cached state values which are subject to change. Where an individual change to a cached state value does not cause it to stray outside its window, then the change is made only to the cached state value, without triggering an updating operation. Where the change causes the cached state value to stray outside the window, an updating operation is triggered. Preferably, the system contains a global system clock, which is adjusted by an independent clock state delta value for each partition. A respective window is maintained for each clock delta. A global wake-up time for the system, determined as the earliest wake-up time of any partition, is re-computed when a change to a partition's clock causes its cached clock delta to stray outside the window.