Poster: No More Slow Messages: Programmable Packet Handling in Hard IRQ

Tail latency in packet handling can easily occur in today's huge distributed systems. Serious failure can happen if a packet experiences tail latency, especially if that packet is used to manage distributed systems. For example, the delay in heartbeat packets results in unnecessary invocation of recovery procedures, and degrades the overall availability of the system. This poster presents a mechanism that handles critical management packets without any tail latency. It handles critical packets inside hard interrupt request (IRQ) contexts to avoid unexpected delay of packet handling due to resource contention. The code for handling management packets is programmable. To allow the installation of user-defined code, it also provides programmable but safe execution environments. Our experimental results demonstrate our system can reduce 99.9 percentile latency up to 74.7% compared to XDP, a state-of-the-art packet handling system.