Maglev Cycle 8: Full-Rate IK Merge
The Context
Cycle 7 confirms routing and merge at 10 Hz. Cycle 8 raises the PCVR client to operating rate — continuous 6-DOF IK at headset cadence — alongside full-rate gamepad input, and verifies the gateway merges both without head-of-line blocking.
The Problem Statement
6-DOF IK datagrams arrive an order of magnitude more frequently than gamepad events. The gateway’s merge path must handle that rate differential without blocking lower-frequency gamepad events. A head-of-line stall on the IK queue would delay or drop gamepad events silently.
Design
The PCVR client sends 6-DOF IK datagrams at full headset rate. The Steam Deck client sends gamepad datagrams at normal cadence. Both arrive on UDP 443. The gateway merges them per tick and forwards to the zone server on UDP 7443. The world is static.
Pass criteria:
Estimate
5 days (2026-05-26 → 2026-06-02). The merge path is an extension of Cycle 7; the risk is head-of-line behaviour under load, which requires profiling time. A hardware re-run on physical Meta Quest hardware before Cycle 9 adds 1 day outside this window.
CRIS Score
| Factor | Score | Evidence |
|---|---|---|
| Complexity | 6 | Merging a continuous high-frequency IK stream with low-frequency gamepad input without head-of-line effects is untested in this codebase. |
| Reach | 10 | Cross-platform play at operating rate requires this path; Cycles 9 and beyond add physics and persistence on top of it. |
| Impediment | 9 | A head-of-line bug here makes physics results in Cycle 9 and beyond unreliable for the gamepad client. |
| Stakeholder | 10 | Gate for cross-platform physics and score. |
| Total | 8.25 | Build after Cycle 7 passes. |
The Downsides
The Meta XR Simulator on macOS covers the initial run, but Cycle 8 must be re-run on physical hardware before Cycle 9 begins — the simulator does not reproduce real headset IK datagram rates under motion.
The Road Not Taken
Skipping Cycles 7 and 5 together was rejected — a failure at full rate conflates routing bugs with rate bugs, leaving both unattributable.
Status
Status: Draft
Decision Makers
- Lead Architect / Fabric Maintainer
Further Reading
@misc{v_sekai_2026,
title = {V-Sekai},
year = {2026},
url = {https://v-sekai.org/}
}