The reports
The Roadmaster went public on the evening of the 29th. By the next morning a player on Nexus had written that they got “a lot of frame jumps every time i put the mod in”, and the first comment on 7daystodiemods reported a massive frame drop on a hosted server. Taroos had felt it too.
What it was
The game’s own log prints an FPS average every 30 seconds, and an average hides a single long frame. So a small probe mod, never released, logged every frame’s length. On 1.5.2, in the world, 94 to 99 frames in every 30 seconds ran longer than 50 ms, about three a second.
That rhythm had a source. From the moment the game loaded the mod, a helper searched every loaded object in the world for Roadmaster trucks and trailers: two searches, every quarter of a second, whether or not a Roadmaster was anywhere in the world, on every player’s game and on dedicated servers. In this world each pair of searches took 50 to 105 ms. Three smaller lookups did the same kind of thing every physics tick: finding the fifth wheel and every free kingpin while the tractor ran without a trailer, the landing-gear support of a hooked-up trailer, and the landing gear of every parked one.
Fixed
Every entity the game makes passes through one spawn step, and the mod already watched it. Each truck and trailer now signs in there, so nothing searches the world anymore. The fifth wheel, kingpins and landing gear are found once and remembered. Nothing about how the rig drives, hooks up or releases changed. The release tool now refuses any build that still contains the search.
Measured
Same world, same spawn, same drive:
| 1.5.2 | 1.5.3 | |
|---|---|---|
| Frames over 50 ms, per 30 s | 94 to 99 | 1 |
| 99th percentile frame | 68 to 82 ms | 7.9 ms |
The rig hooked up on the first pass, and the coupled pair came back after a save and reload. Clean boot. Taroos, after the drive: “omg it really was our mod, the game is buttery smooth again.”