WorstCaseLatenz

WorstCaseLatenz is the maximum time from when an input event occurs to when the system produces the expected observable response under worst-case operating conditions. It is a key metric in real-time and embedded systems, where timing guarantees are essential. Unlike average latency, which describes typical behavior, worst-case latency bounds the upper limit of delays a system may exhibit, including delays from scheduling, interrupts, and hardware access.

Estimating and enforcing WorstCaseLatenz often involves static timing analysis and consideration of several delay components: the worst-case execution time (WCET) of tasks, interrupt latency, queuing and contention delays in schedulers and communication channels, and synchronization or inter-process communication delays. Factors such as processor workload, memory access patterns, cache effects, device I/O, and network traffic can influence the bound.

Design approaches to reduce or bound WCL include deterministic scheduling policies (for example fixed priority or earliest deadline first), time-triggered architectures, bounded interrupt disable times, and isolation in virtualization environments. In networking and storage systems, bounded delays arise from transmission time, buffering, and queueing disciplines. Limitations of WorstCaseLatenz estimates include potential pessimism in bounds and inaccuracies in WCET measurements. Nonetheless, a well-defined WorstCaseLatenz provides a basis for verifying timing requirements, ensuring safety-critical performance, and comparing real-time designs.