arXiv:2602.04013 · v2

Pending Conflicts Make Progress Impossible

首次提交 2026-02-04 05:00

版本更新 2026-11-12 18:21

雷达观测 2026-11-13 14:15

摘要

In this work, we study progress conditions for commutativity-aware, linearizable implementations of shared objects. Motivated by the observation that commuting operations can be executed in parallel, we introduce conflict-obstruction-freedom: a process is guaranteed to complete its operation if it runs for long enough without encountering step contention with conflicting (non-commuting) operations. This condition generalizes obstruction-freedom and wait-freedom by allowing progress as long as step contention is only induced by commuting operations. We prove that conflict-obstruction-free universal constructions are impossible to implement in the asynchronous read-write shared memory model. This result exposes a fundamental limitation of conflict-aware universal constructions: the mere invocation of conflicting operations imposes a synchronization cost. Progress requires eventual resolution of pending conflicts.

作者备注：10 pages, 2 figures

期刊信息：Information Processing Letters. 2027. Vol 196