Modeling and Performance Analysis of P4 Programmable Devices

In our digitized society, emerging applications require highly performant and flexible networks that can adapt to satisfy varying connectivity needs. P4 as a domain-specific programming language for data plane pipelines introduces the required flexibility through easy-to-use programmability. However, the performance of P4-capable devices is still an open question that has not yet been completely addressed. Understanding whether a P4-enabled device can meet the performance requirements for a specific network function pipeline is key for planning as well as deployment scenarios in a communication provider network. In this paper, we propose a simple analytical model that can quickly predict the performance of network functions written in P4 for a given device. The programmable data plane of P4 devices is modeled as a forward queuing system with a variable service rate that depends on the complexity of the configured data path program. On top of the data plane model, the controller's interaction is modeled as a feedback queuing system. We evaluate the accuracy of our model through a parameter study and simulation. The evaluation reveals corner cases, which are analyzed to formalize a constraint on the service rate using model parameters to guarantee stable system performance.