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This feature is exclusive to Java Edition. 
perf
Permission level
required

4

Restrictions

Dedicated server only

Captures information and metrics about the game for ten seconds.

Note that this coomand can only executed in dedicated server, use F3 + l in client to run performance profiler.

Syntax[]

perf start
Starts a recording for 10 seconds performance profiling such as tick durations, used heap sizes and other more detailed stats.
perf stop
Ends the recording early before the 10-second limit.

Result[]

CommandTriggerJava Edition
/perf starta perf profiling session has already been started Failed
/perf stopthere's no perf profiling session running.
anyOn successStarts/stops the perf profiling.

Outputs[]

CommandEditionSituationSuccess Count/execute store success .../execute store result ...
anyJava EditionOn failN/A00
On successN/A10

File structure[]

When perf profiling session is stopped, a ZIP file is created in .minecraft/debug/profiling with the following structure:

  • yyyy-MM-dd_HH.mm.ss-<world name>-<game version>.zip
    • system.txt
    • server
      • deviations
        • ticktime
          • <current tick>@yyyy-MM-dd_HH.mm.ss.SSS.txt
      • levels
        • <namespace>
          • <dimension name>
            • block_entities.csv: Contains a list of block entities in the world in the format x,y,z,type.
            • chunks.csv: Contains a list of chunk information in the format x,z,level,in_memory,status,full_status,accessible_ready,ticking_ready,entity_ticking_ready,ticket,spawning,entity_count,block_entity_count.
            • entities.csv: Contains a list of entities in the world in the format x,y,z,uuid,type,alive,custom_name.
            • entity_chunks.csv: Contains a list of loaded chunks in the dimension in the format x,y,z,visibility,load_status,entity_count.
            • example_crash.txt: An example crash file.
            • stats.txt: Contains some stats.
      • metrics
        • cpu.csv
        • event_loops.csv
        • jvm.csv
        • mailboxes.csv
        • ticking.csv
      • classpath.txt: Contains the file paths of the external jars Minecraft uses.
      • gamerules.txt: A plain text file containing a list of game rules and their values (<gamerule>=<value>).
      • modules.txt: Contains the external modules jars Minecraft uses.
      • profiling.txt: The profiler results.
      • server.properties.txt: Current server.properties.
      • stats.txt: Contains some stats.
      • threads.txt: All running threads.

History[]

Java Edition
1.17Pre-release 1Added /perf.
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