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Crafting Table JE4 BE3.png
This article describes content that may be included in Java Edition. 
This content has appeared in Java Edition development versions, but the full update containing it has not been released yet.

Start profiling with Java FlightRecorder as well as a few custom events.

Syntax[]

jfr (start|stop)

Arguments[]

start

Start JFR profiling.

stop

Stop JFR profiling.

Result[]

Profiling contains several custom events below:

  • minecraft.ServerTickTime: sampling event exposing average server tick times at one second intervals.
  • minecraft.ChunkGeneration: time taken to generate individual chunk stages.
  • minecraft.PacketRead | minecraft.PacketSent:network traffic.
  • minecraft.WorldLoadFinishedEvent: initial world loading duration.

A summary JSON report is written both to the log file and in the debug folder accompanied by a .jfr recording ready to be analyzed in i.e JMC or any other profiler tool supporting the format.

Output[]

The results in `/execute store result` are the opposite to most commands - whether this is intentional or not is unknown.

CommandEditionSituationSuccess Count/execute store success .../execute store result ...
/jfr startJava EditionOn fail001
On success110
/jfr stopOn fail001
On success110

History[]

Upcoming Java Edition
1.1821w37aAdded /jfr.
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