Find Your First Desync in 15 Minutes

Description and use

Tickwise lets developers quickly locate the first divergent tick in deterministic multiplayer games by recording per‑tick hashes, comparing recordings, and diffing state dumps, cutting debugging time from weeks to minutes.

Problem

Debugging a desync in deterministic multiplayer games is expensive because the symptom appears far from the cause and reproducing the exact run is hard.

Outcome

Tickwise reduces desync debugging from weeks to minutes by automating recording, comparison, and state diffing, enabling quick identification of the exact field causing divergence.

Workflow

• Record inputs and per‑tick hashes on each client into .rec files.
• Run tickwise compare a.rec b.rec to find the first tick where hashes disagree and which hash caught it.
• Replay each recording in your own loop, dumping state at the reported tick into .dump files.
• Run tickwise diff a.dump b.dump to list all differing fields and their values.
• Investigate the differing fields to fix the underlying determinism bug.

Evidence

Tickwise is a Rust library and a command line tool. The library sits inside your game loop and watches. It never runs your simulation and never touches your netcode.

Source

tickwise compare a.rec b.rec reports the first tick where the recorded hashes disagree, and which hash caught it.

Source