When P4 Meets Run-to-completion Architecture

P4 programmable data planes have significantly accelerated the evolution of various network technologies. Although the P4 language has gained wide acceptance, its further development encounters two obstacles: limited programmability and the cessation of the next-generation Tofino chip. As a hardware manufacturer, we try to address the above dilemmas by opening the P4 programmability of our run-to-completion (RTC) chips. At present, there is no publicly available experience in this field. We introduce P4RTC, a comprehensive consolidation of our experiences applying the P4 language to RTC architecture. P4RTC introduces a new P4 architecture model and a set of beneficial extern constructs to fully leverage the RTC architecture's programmability. Besides, we share the insights we have gained from designing and implementing compilers. We also provide a performance model to facilitate profiling P4RTC's performance on user-customized P4 code. We prototype P4RTC on an RTC chip with 1.2 Tbps bandwidth. Case-oriented evaluation demonstrates that P4RTC can enhance P4 programmability and reduce the burdens of RTC development. The performance model can provide substantial insights into optimizing P4RTC programs.