Spark: The Ultimate Lag Diagnosis Tool
If your server is experiencing TPS drops (low "Ticks Per Second"), you need a profiler. Spark is the best-in-class tool for spotting laggy plugins, mods, or entities.
1. Installation
Download Spark from Spark Website. It works on Paper, Spigot, Forge, and Fabric.
2. Running a Performance Profile
When the server is lagging, run this command in console or in-game:
/spark profiler start
Wait for 3-5 minutes while the server is under load (players are playing), then run:
/spark profiler stop
3. Analyzing the Results
Spark will generate a link. Open it and look for the "Flame Graph" or "Call Tree".
- Broad bars: Represent high CPU usage.
- Plugin names: If a plugin name (like Essentials or WorldGuard) takes up 30% of the bar, it's causing the lag.
- Event loops: Look for
TickEntityorTickTileEntityto see if specific mobs (like 500 sheep) are the culprit.
4. Monitoring TPS & Health
Use /spark health to see a live summary of:
- TPS: Current ticks per second (Goal: 20.0).
- MSPT: Milliseconds per tick (Anything over 50.0ms causes lag).
- Memory: Heap usage vs. allocation.
Pro Tip: Most lag in 2026 is caused by unoptimized chunk loading or too many entities in a small area. Use Spark to identify exactly which player's farm is to blame!