What is a timing anomaly

Timing anomalies make worst-case execution time analysis much harder, because the analysis will have to consider all local choices. It has been widely recognised that certain hardware features are timing anomalous, while others are not. However, defining formally what a timing anomaly is, has been difficult. We examine previous definitions of timing anomalies, and identify examples where they do not align with common observations. We then provide a definition for consistently slower hardware traces that can be used to define timing anomalies and aligns with common observations. 1998 ACM Subject Classification C.4 [Performance of systems]: Modelling techniques, Perfor-mance attributes Keywords and phrases Timing anomalies, worst case execution time (WCET), abstraction