How to Create a Performance Profile for your Minecraft Server

If you’re having performance problems on your server, creating a profile with Spark can help you pinpoint exactly what’s causing it. Rather than guessing which plugin, mod, or part of your world is responsible, Spark gives you a detailed breakdown of where your server is actually spending its time, down to specific methods and functions. This guide walks you through setting it up and running your first profile.

Setting Up Spark

1. Download Spark for your server type.
2. Open the AleForge Panel.
3. Go to the Console tab and make sure your server is stopped.
4. Go to the Files tab.
5. Upload Spark to the correct folder for your server type:
   • Forge or Fabric servers: upload it to the mods folder.
   • Spigot (and Paper) servers: upload it to the plugins folder.
6. Go back to the Console tab and start your server.

Running a Profile

1. To start profiling, run the following command in the console:

spark profiler start

2. Let it run for a bit while your server experiences normal activity, including whatever was causing the lag, if you can reproduce it. The longer it runs during the actual problem, the more useful data you’ll get.
3. If you’d like to view the profile while it’s still running, use:

spark profiler open

This opens a link to an interactive, web-based view of the profile, where you can see exactly what’s consuming the most time on your server.

4. Once you’re done, stop profiling with:

spark profiler stop

This also gives you a link to view the finished report, in case you didn’t open it while it was still running.

Reading the Results

Spark’s report shows where your server’s tick time is going, broken down by plugin, mod, and individual function calls. A healthy server runs right around 20 TPS. Look for entries taking up a large percentage of the tick:

• Entities or mob AI taking most of the tick: You likely have too many mobs loaded at once (villagers are a common cause). Follow How to Reduce Entity Lag on a Minecraft Server and lower your view distance and simulation distance. Setting both to 8 in server.properties is a good starting point. Note that these are server config settings, not your in-game video settings.
• Thousands of loaded chunks with only a few players online: Lower view-distance and simulation-distance in server.properties.
• Running Fabric: Install server-side optimization mods like ModernFix, Lithium, and Krypton.

If you’re not sure how to read the report, contact support with your Spark link and server ID and we’ll help you look through it.