# mc-bench — Minecraft Server Load Benchmark

Benchmarks vanilla vs patched Minecraft server-26.1 under simulated load.

## Setup

```bash
# JDK 25 required
JAVA=/tmp/jdk25/bin/java
# Server jar (bundler)
SERVER_JAR=/home/fox/Downloads/server.jar
# Install both servers
bash bench-server.sh vanilla 40
bash bench-server.sh patched 40
```

## Tools

| File | Purpose |
|------|---------|
| `bench-server.sh` | Full benchmark: startup + `/reload` + bot wave |
| `gen-modpack-tags.py` | Generates synthetic depth-N diamond tag data |
| `raw-connect.mjs` | Raw TCP handshake bot (version-agnostic) |
| `sim-players.mjs` | mineflayer bot runner (requires matching protocol version) |
| `rcon.py` | RCON command injection |

## What it measures

- **Startup time** (wall clock, JVM launch → "Done")
- **/reload time** (RCON-triggered, measures tag reload)
- **Connection capacity** (how many handshakes the server accepts simultaneously)
- **Handshake latency** (p50/p95/max)

## Notes

- Real-world improvement requires a genuine modpack with tag depth ≥ 10.
- Synthetic tag data uses HashMap iteration (hash-ordered), which may not trigger
  worst-case DFS. Real modpacks load tags alphabetically (base before root) which
  reliably triggers the exponential in vanilla.
- See `tests/bench/LoadSimBenchmark.java` for controlled algorithmic benchmark.