Optimizing Record/Replay Through Relaxed Total Ordering and Multi-Version eXecution (Artifact)

Abstract

Support for Record Replayer (RR) introduces a non-negligible amount of performance overhead, which limits its applicability. Two main sources of such overhead in state-of-the-art RR systems are: multi-threading, and I/O bound workloads. To address the former, we introduce Relaxed Total Order (RTO), an online-computable weakening of total order that preserves the cross-thread constraints needed for replay while avoiding unnecessary serialization. RTO is compatible with Multi-Version eXecution (MVX), enabling online deterministic replay without pre-processing the recording log or heavyweight coordination. To address the latter, we combine RR with Multi-Version eXecution (MVX) to eliminate RR’s poor performance on I/O-bound workloads. Our hybrid design uses a follower variant to absorb the overhead needed for logging and I/O, keeping the user-facing leader off the critical path. The artifact contains the source code of our prototype, software used to evaluate the techniques' performance, and scripts to automate and summarize the results.