2

My jfr log does not contain any information about Memory / TLAB Allocation section , if analyze it by MissionControl

JVM parameters (JDK17):

-XX:+UnlockDiagnosticVMOptions -X::+DebugNonSafepoints -XX:UnlockCommercialFeatures -XX:+FlightRecorder -XX:StartFlightRecording=delay....filename=... loglevel=info

P.S. FlightRecorderOptions decom'ed and not available in LTS JDK17

JVM parameters (JDK8):

-XX:+UnlockDiagnosticVMOptions -X::+DebugNonSafepoints -XX:UnlockCommercialFeatures -XX:+FlightRecorder -XX:StartFlightRecording=delay....filename=... -XX:FlightRecorderOptions=loglevel=info

On JDK8 I have all data in place, I'm a bit puzzled what if my issue about missing 'Memory/TLAB Allocation' is caused by incorrect JVM parameters for JFR ?

--Update--

https://bugs.openjdk.org/browse/JDK-8225312 Deprecate -XX:FlightRecorder

27P
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  • @Holger Yes, I meant jfr file i.e. in MissionControl 'Memory/TLAB' stats is not available for me with the above JDK17 JVM params – 27P Jun 13 '23 at 10:59

2 Answers2

1

The TLAB events were disabled in settings=profile when the Object Allocation Sample event was introduced in JDK 16 (as it has less overhead and is enabled by default)

You can enable TLAB events manually:

java -XX:StartFlightRecording:
         jdk.ObjectAllocationInNewTLAB#enabled=true,
         jdk.ObjectAllocationOutsideTLAB#enabled=true,filename=...
Kire Haglin
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0

Adding -XX:+UseTLAB as a parameter should do the trick.

Hope that works/helps.

Cheers

Z-100
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  • HI, Unfortunately it did not do any trick when using -XX:+UseTLAB, I still do not have Memory(Classes stats) and TLAB statistics in MissionControl when opening my jfr – 27P Jun 13 '23 at 11:11