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Performance
This page gives the main numbers. The benchmark page has every table, the method, and the costs.
The numbers come from JMH benchmarks, run in October 2026 on a shared 4 core cloud machine with Java 21, with Celeris 0.2.3 (the physics kernel has since become 7 to 20 percent slower because it now checks every item for impossible values). The engine comparison in the Benchmarks page can be reproduced with ./gradlew benchmarkTest. Your numbers will differ. Read differences under about 20 percent as a tie. The ratios are what matter.
| Job | Celeris | Java's built-in code | Result |
|---|---|---|---|
| Compress 38 KiB of mod data | Native zstd: 542 MiB per second | Java Deflater: 42 MiB per second | 12.8 times faster, for almost the same size |
| Decompress the same data | 1,296 MiB per second | Java Inflater: 417 MiB per second | 3.1 times faster |
Celeris is about as fast as zstd-jni, the usual Java zstd library. Its jar is about 2 MB, against 7.4 MB for zstd-jni.
- 32,768 dropped items moved in 0.88 ms per tick, on 3 threads, with the native kernel. A game tick lasts 50 ms at 20 ticks per second, so this is under 2 percent of a tick.
- The same rules in plain Java, on one thread, take 4.72 ms. That is 5.3 times longer.
- Finding the items that touch each other in a pile of 16,384 takes 0.24 ms. Before, the same search could take close to a second.
- One worker thread handing results to the game thread: 39.5 million per second. JCTools, a well known lock-free queue library, does 8.0 million per second. That is 4.9 times faster.
- With two or three workers, Celeris is still 1.3 to 1.5 times faster than JCTools.
100,000 items travelling on 200-block pipes take 101 microseconds per tick. One object per item takes 261 microseconds. On 20-block pipes the two are about equal.
Velox is a server mod built on Celeris. On a server with Minecraft 1.21.1 and 20,000 dropped items, Velox takes 18.3 ms per tick. Vanilla NeoForge takes 243.0 ms. That is 13.3 times faster, and it takes the server from about 4 ticks per second to a full 20 (measured on 2026-10-29, one run on a shared GitHub runner).
