Hardware-Software Co-Design for Network Performance Measurement

Abstract

Diagnosing performance problems in networks is important, for example to determine where packets experience high latency or loss. However, existing performance diagnoses are constrained by limited switch mechanisms for measurement. Alternatively, operators use endpoint information indirectly to infer root causes for problematic latency or drops. Instead of designing piecemeal solutions to work around such switch restrictions, we believe that the right approach is to co-design language abstractions and switch hardware primitives for network performance measurement. This approach provides confidence that the switch primitives are sufficiently general, i.e., they can support a variety of existing and unanticipated use cases. We present a declarative query language that allows operators to ask a diverse set of network performance questions. We show that these queries can be implemented efficiently in switch hardware using a novel programmable key-value store primitive. Our preliminary evaluations show that our hardware design is feasible at modest chip area overhead relative to existing switching chips.