Dev Blog· 3 min
Game start: from 3:34 minutes to 9 seconds
The new launch window times every step. That made the cause of a three-minute startup easy to find.
The launch window shows 11 steps with timings, progress, time remaining and a live log. That's exactly how we noticed that launching 1.21.11 with Fabric sometimes took more than three minutes.
The cause
An automatically created class archive (AppCDS) cost three minutes whenever it was missing or invalidated by a loader or Java update – and saved 0.1 s at best, because Fabric loads the game classes itself. The archive is gone, and the launcher deletes old archives at startup.
| Measurement (1.21.11 Fabric, Java 21) | to title screen |
|---|---|
| Class archive missing or outdated | ≈ 210 s |
| Without class archive (now) | 9.2 s |
| First launch of a folder | 17.7 s |
Fixed along the way
- The companion mod ships fabric-transitive-access-wideners-v1, because two render pipelines are private in Minecraft.
- In 1.21.10 and 1.21.11, all mod resources were missing without fabric-resource-loader-v1 – which caused the crash “post chain apophis:grading”.