Introduction

The following are the events for the OpenJDK 21 (jdk-21.0.2+0, 27-November-2023). The events are collected from the event configuration and the source code. Visit jfreventcollector for more information. this is also the place you can contribute additional event descriptions, if you don't want to contribute them directly to the OpenJDK. The site generator lives on GitHub too.

This page is maintained by Johannes Bechberger of the SapMachine team at SAP and contributors.

Some events have fake end times / durations, these are hidden in the event description here.

Flight Recorder

DumpReason

default profiling startTime 11 17 21 22

Category: Flight Recorder

Who requested the recording and why

Configuration	enabled
default	true
profiling	true

Field	Type	Description
reason	string	Reason Reason for writing recording data to disk
recordingId	int	Recording Id Id of the recording that triggered the dump, or -1 if it was not related to a recording

DataLoss

default profiling startTime 11 17 21 22

Category: Flight Recorder

Data could not be copied out from a buffer, typically because of contention

Configuration	enabled
default	true
profiling	true

Field	Type	Description
amount	ulong: bytes	Amount Amount lost data
total	ulong: bytes	Total Total lost amount for thread

Flush

experimental startTime duration 14 17 21 22

Category: Flight Recorder

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	threshold
default	false	0 ns
profiling	false	0 ns

Field	Type	Description
flushId	ulong	Flush Identifier
elements	ulong	Elements Written
size	ulong: bytes	Size Written

Examples 3

elements	ulong	857
flushId	ulong	44
size	ulong: bytes	434690
startTime	long: millis	51847140375

elements	ulong	354
flushId	ulong	52
size	ulong: bytes	441913
startTime	long: millis	56179944084

elements	ulong	137
flushId	ulong	70
size	ulong: bytes	120975
startTime	long: millis	76980740833

ActiveRecording

default profiling startTime duration stackTrace 11 17 21 22

Source src/jdk.jfr/share/classes/jdk/jfr/events/ActiveRecordingEvent.java

Category: Flight Recorder

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
id	long	Id
name	string	Name Consider contributing a description to jfreventcollector.
destination	string	Destination Consider contributing a description to jfreventcollector.
disk	boolean 21+	To Disk
maxAge	long: millis	Max Age
flushInterval	long: millis 14+	Flush Interval
maxSize	long: bytes	Max Size
recordingStart	long: epochmillis	Start Time
recordingDuration	long: millis	Recording Duration

Examples 3

destination	string	[...]/code/experiments/jfreventcollector/jfr/sample_UseParallelGC.jfr
disk	boolean	true
flushInterval	long: millis	1000
id	long	1
maxAge	long: millis	9223372036854775807
maxSize	long: bytes	262144000
name	string	1
recordingDuration	long: millis	9223372036854775807
recordingStart	long: epochmillis	1701099063735
stackTrace	StackTrace	null
startTime	long: millis	46912624834

destination	string	[...]/code/experiments/jfreventcollector/jfr/sample_UseSerialGC.jfr
disk	boolean	true
flushInterval	long: millis	1000
id	long	1
maxAge	long: millis	9223372036854775807
maxSize	long: bytes	262144000
name	string	1
recordingDuration	long: millis	9223372036854775807
recordingStart	long: epochmillis	1701099181498
stackTrace	StackTrace	null
startTime	long: millis	86681976541

destination	string	[...]/code/experiments/jfreventcollector/jfr/sample_UseG1GC.jfr
disk	boolean	true
flushInterval	long: millis	1000
id	long	1
maxAge	long: millis	9223372036854775807
maxSize	long: bytes	262144000
name	string	1
recordingDuration	long: millis	9223372036854775807
recordingStart	long: epochmillis	1701098850537
stackTrace	StackTrace	null
startTime	long: millis	192132299750

ActiveSetting

default profiling startTime duration stackTrace 11 17 21 22

Source src/jdk.jfr/share/classes/jdk/jfr/events/ActiveSettingEvent.java

Category: Flight Recorder

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
id	long	Event Id
name	string	Setting Name
value	string	Setting Value

Examples 3

id	long	49
name	string	threshold
stackTrace	StackTrace	null
startTime	long: millis	688133083
value	string	0 ms

id	long	12
name	string	enabled
stackTrace	StackTrace	null
startTime	long: millis	339201541
value	string	true

id	long	11
name	string	threshold
stackTrace	StackTrace	null
startTime	long: millis	479682042
value	string	10 ms

JVM

JVMInformation

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine

Description of JVM and the Java application

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
jvmName	string	JVM Name
jvmVersion	string	JVM Version
jvmArguments	string	JVM Command Line Arguments
jvmFlags	string	JVM Settings File Arguments
javaArguments	string	Java Application Arguments
jvmStartTime	long: epochmillis	JVM Start Time
pid	long	Process Identifier

Examples 3

javaArguments	string	[...]/code/experiments/jfreventcollector/.cache/renaissance.jar -t 5 -r 1 all
jvmArguments	string	-XX:StartFlightRecording=filename=[...]/code/experiments/jfreventcollector/jfr/sample_UseG1GC.jfr,settings=[...]/code/experiments/jfreventcollector/.cache/jfc.jfc -XX:+UseG1GC
jvmFlags	string	null
jvmName	string	OpenJDK 64-Bit Server VM
jvmStartTime	long: epochmillis	1701098849915
jvmVersion	string	OpenJDK 64-Bit Server VM (21.0.1+12-LTS) for bsd-aarch64 JRE (21.0.1+12-LTS), built on 2023-10-17T00:00:00Z by "admin" with clang Apple LLVM 12.0.0 (clang-1200.0.32.29)
pid	long	15986
startTime	long: millis	135012505000

javaArguments	string	[...]/code/experiments/jfreventcollector/.cache/renaissance.jar -t 5 -r 1 all
jvmArguments	string	-XX:StartFlightRecording=filename=[...]/code/experiments/jfreventcollector/jfr/sample_UseSerialGC.jfr,settings=[...]/code/experiments/jfreventcollector/.cache/jfc.jfc -XX:+UseSerialGC
jvmFlags	string	null
jvmName	string	OpenJDK 64-Bit Server VM
jvmStartTime	long: epochmillis	1701099181221
jvmVersion	string	OpenJDK 64-Bit Server VM (21.0.1+12-LTS) for bsd-aarch64 JRE (21.0.1+12-LTS), built on 2023-10-17T00:00:00Z by "admin" with clang Apple LLVM 12.0.0 (clang-1200.0.32.29)
pid	long	16877
startTime	long: millis	48587905500

javaArguments	string	[...]/code/experiments/jfreventcollector/.cache/renaissance.jar -t 5 -r 1 all
jvmArguments	string	-XX:StartFlightRecording=filename=[...]/code/experiments/jfreventcollector/jfr/sample_UseParallelGC.jfr,settings=[...]/code/experiments/jfreventcollector/.cache/jfc.jfc -XX:+UseParallelGC
jvmFlags	string	null
jvmName	string	OpenJDK 64-Bit Server VM
jvmStartTime	long: epochmillis	1701099063338
jvmVersion	string	OpenJDK 64-Bit Server VM (21.0.1+12-LTS) for bsd-aarch64 JRE (21.0.1+12-LTS), built on 2023-10-17T00:00:00Z by "admin" with clang Apple LLVM 12.0.0 (clang-1200.0.32.29)
pid	long	16596
startTime	long: millis	20953202542

InitialSystemProperty

default profiling startTime end chunk 11 17 21 22

Category: Java Virtual Machine

System Property at JVM start

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
key	string	Key
value	string	Value

Examples 3

key	string	java.vm.version
startTime	long: millis	340530041
value	string	21.0.1+12-LTS

key	string	java.library.path
startTime	long: millis	98899630834
value	string	[...]/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.

key	string	jdk.debug
startTime	long: millis	75467363958
value	string	release

JVM: Class Loading

ClassLoad

startTime duration eventThread stackTrace 11 17 21 22

Category: Java Virtual Machine / Class Loading

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	stackTrace	threshold
default	false	true	0 ms
profiling	false	true	0 ms

Field	Type	Description
loadedClass	Class	Loaded Class Consider contributing a description to jfreventcollector.
definingClassLoader	ClassLoader	Defining Class Loader Consider contributing a description to jfreventcollector.
initiatingClassLoader	ClassLoader	Initiating Class Loader Consider contributing a description to jfreventcollector.

Examples 3

definingClassLoader	ClassLoader
name	string	bootstrap
type	Class	null
initiatingClassLoader	ClassLoader
name	string	bootstrap
type	Class	null
loadedClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/logging/SimpleFormatter
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.logging
name	string	java.logging
version	string	21.0.1
name	string	java/util/logging
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	0
lineNumber	int	-1
method	Method
descriptor	string	(Ljava/lang/String;)Ljava/lang/Class;
hidden	boolean	false
modifiers	int	266
name	string	findBootstrapClass
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	1057
name	string	java/lang/ClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
type	FrameType	Native
		…
truncated	boolean	false
startTime	long: millis	711856500

definingClassLoader	ClassLoader
name	string	bootstrap
type	Class	null
initiatingClassLoader	ClassLoader
name	string	bootstrap
type	Class	null
loadedClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/logging/StreamHandler
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.logging
name	string	java.logging
version	string	21.0.1
name	string	java/util/logging
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	0
lineNumber	int	-1
method	Method
descriptor	string	(Ljava/lang/String;)Ljava/lang/Class;
hidden	boolean	false
modifiers	int	266
name	string	findBootstrapClass
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	1057
name	string	java/lang/ClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
type	FrameType	Native
		…
truncated	boolean	false
startTime	long: millis	508537167

definingClassLoader	ClassLoader
name	string	app
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	jdk/internal/loader/ClassLoaders$AppClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	jdk/internal/loader
initiatingClassLoader	ClassLoader
name	string	app
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	jdk/internal/loader/ClassLoaders$AppClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	jdk/internal/loader
loadedClass	Class
classLoader	ClassLoader
name	string	app
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	jdk/internal/loader/ClassLoaders$AppClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	jdk/internal/loader
hidden	boolean	false
modifiers	int	49
name	string	org/renaissance/core/Logging
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	app
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	jdk/internal/loader/ClassLoaders$AppClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	jdk/internal/loader
location	string	null
name	string	null
version	string	null
name	string	org/renaissance/core
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	2
lineNumber	int	21
method	Method
descriptor	string	()V
hidden	boolean	false
modifiers	int	8
name	string	<clinit>
type	Class
classLoader	ClassLoader
name	string	app
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	jdk/internal/loader/ClassLoaders$AppClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	jdk/internal/loader
hidden	boolean	false
modifiers	int	49
name	string	org/renaissance/core/Launcher
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	app
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	jdk/internal/loader/ClassLoaders$AppClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	jdk/internal/loader
location	string	null
name	string	null
version	string	null
name	string	org/renaissance/core
type	FrameType	Interpreted
truncated	boolean	false
startTime	long: millis	360709750

ClassDefine

startTime eventThread stackTrace 11 17 21 22

Category: Java Virtual Machine / Class Loading

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	stackTrace
default	false	true
profiling	false	true

Field	Type	Description
definedClass	Class	Defined Class Consider contributing a description to jfreventcollector.
definingClassLoader	ClassLoader	Defining Class Loader Consider contributing a description to jfreventcollector.

Examples 3

definedClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	java/util/Formatter$Flags
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util
definingClassLoader	ClassLoader
name	string	bootstrap
type	Class	null
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	4
lineNumber	int	2924
method	Method
descriptor	string	(Ljava/lang/String;II)V
hidden	boolean	false
modifiers	int	2
name	string	flags
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	java/util/Formatter$FormatSpecifier
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util
type	FrameType	Interpreted
		…
truncated	boolean	false
startTime	long: millis	515391250

definedClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	48
name	string	java/util/regex/Pattern$Branch
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util/regex
definingClassLoader	ClassLoader
name	string	bootstrap
type	Class	null
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	812
lineNumber	int	3259
method	Method
descriptor	string	()Ljava/util/regex/Pattern$Node;
hidden	boolean	false
modifiers	int	2
name	string	group0
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	49
name	string	java/util/regex/Pattern
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util/regex
type	FrameType	Interpreted
		…
truncated	boolean	false
startTime	long: millis	363969750

definedClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	1537
name	string	sun/util/locale/provider/AvailableLanguageTags
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	sun/util/locale/provider
definingClassLoader	ClassLoader
name	string	bootstrap
type	Class	null
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	0
lineNumber	int	221
method	Method
descriptor	string	()Ljava/text/spi/DecimalFormatSymbolsProvider;
hidden	boolean	false
modifiers	int	4098
name	string	lambda$getDecimalFormatSymbolsProvider$4
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	sun/util/locale/provider/JRELocaleProviderAdapter
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	sun/util/locale/provider
type	FrameType	Interpreted
		…
truncated	boolean	false
startTime	long: millis	721852041

ClassRedefinition

default profiling startTime 15 17 21 22

Category: Java Virtual Machine / Class Loading

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
redefinedClass	Class	Redefined Class Consider contributing a description to jfreventcollector.
classModificationCount	int	Class Modification Count The number of times the class has changed
redefinitionId	ulong	Class Redefinition Id

RedefineClasses

default profiling startTime duration eventThread stackTrace 15 17 21 22

Category: Java Virtual Machine / Class Loading

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	stackTrace	threshold
default	true	true	0 ms
profiling	true	true	0 ms

Field	Type	Description
classCount	int	Class Count
redefinitionId	ulong	Class Redefinition Id

RetransformClasses

default profiling startTime duration eventThread stackTrace 15 17 21 22

Category: Java Virtual Machine / Class Loading

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	stackTrace	threshold
default	true	true	0 ms
profiling	true	true	0 ms

Field	Type	Description
classCount	int	Class Count
redefinitionId	ulong	Class Redefinition Id

ClassUnload

startTime eventThread 11 17 21 22

Category: Java Virtual Machine / Class Loading

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	false
profiling	false

Field	Type	Description
unloadedClass	Class	Unloaded Class Consider contributing a description to jfreventcollector.
definingClassLoader	ClassLoader	Defining Class Loader Consider contributing a description to jfreventcollector.

Examples 3

definingClassLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
startTime	long: millis	4057416625
unloadedClass	Class
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
hidden	boolean	false
modifiers	int	1537
name	string	scala/collection/immutable/SortedSetOps
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
location	string	null
name	string	null
version	string	null
name	string	scala/collection/immutable

definingClassLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
startTime	long: millis	8802329625
unloadedClass	Class
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
hidden	boolean	false
modifiers	int	1537
name	string	scala/collection/immutable/IndexedSeqOps
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
location	string	null
name	string	null
version	string	null
name	string	scala/collection/immutable

definingClassLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
startTime	long: millis	5904962459
unloadedClass	Class
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
hidden	boolean	true
modifiers	int	4144
name	string	org.apache.spark.internal.config.package$$$Lambda+0x0000000800376000/283923004
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
location	string	null
name	string	null
version	string	null
name	string	org/apache/spark/internal/config

JVM: Code Cache

CodeCacheFull

default profiling startTime eventThread 11 17 21 22

Category: Java Virtual Machine / Code Cache

A code heap is full, this leads to disabling the compiler

Configuration	enabled
default	true
profiling	true

Field	Type	Description
codeBlobType	CodeBlobType	Code Heap Consider contributing a description to jfreventcollector.
startAddress	ulong: address	Start Address
commitedTopAddress	ulong: address	Commited Top
reservedTopAddress	ulong: address	Reserved Top
entryCount	int	Entries
methodCount	int	Methods
adaptorCount	int	Adaptors
unallocatedCapacity	ulong: bytes	Unallocated
fullCount	int	Full Count
codeCacheMaxCapacity	ulong: bytes 17+	Code Cache Maximum Capacity

CodeCacheStatistics

default profiling startTime every chunk 11 17 21 22

Category: Java Virtual Machine / Code Cache

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	everyChunk
profiling	true	everyChunk

Field	Type	Description
codeBlobType	CodeBlobType	Code Heap Consider contributing a description to jfreventcollector.
startAddress	ulong: address	Start Address
reservedTopAddress	ulong: address	Reserved Top
entryCount	int	Entries
methodCount	int	Methods
adaptorCount	int	Adaptors
unallocatedCapacity	ulong: bytes	Unallocated
fullCount	int	Full Count

Examples 3

adaptorCount	int	0
codeBlobType	CodeBlobType	CodeHeap 'non-profiled nmethods'
entryCount	int	3144
fullCount	int	0
methodCount	int	3144
reservedTopAddress	ulong: address	4778721280
startAddress	ulong: address	4655808512
startTime	long: millis	38504740458
unallocatedCapacity	ulong: bytes	117436032

adaptorCount	int	486
codeBlobType	CodeBlobType	CodeHeap 'non-nmethods'
entryCount	int	576
fullCount	int	0
methodCount	int	0
reservedTopAddress	ulong: address	4652564480
startAddress	ulong: address	4646715392
startTime	long: millis	46408567292
unallocatedCapacity	ulong: bytes	4466816

adaptorCount	int	0
codeBlobType	CodeBlobType	CodeHeap 'non-profiled nmethods'
entryCount	int	3088
fullCount	int	0
methodCount	int	3088
reservedTopAddress	ulong: address	5486149632
startAddress	ulong: address	5363236864
startTime	long: millis	117193288625
unallocatedCapacity	ulong: bytes	116988416

CodeCacheConfiguration

default profiling startTime end chunk 11 17 21 22

Category: Java Virtual Machine / Code Cache

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
initialSize	ulong: bytes	Initial Size
reservedSize	ulong: bytes	Reserved Size
nonNMethodSize	ulong: bytes	Non-nmethod Size
profiledSize	ulong: bytes	Profiled Size
nonProfiledSize	ulong: bytes	Non-profiled Size
expansionSize	ulong: bytes	Expansion size
minBlockLength	ulong: bytes	Minimum Block Length
startAddress	ulong: address	Start Address
reservedTopAddress	ulong: address	Reserved Top

Examples 3

expansionSize	ulong: bytes	65536
initialSize	ulong: bytes	2555904
minBlockLength	ulong: bytes	6
nonNMethodSize	ulong: bytes	5839564
nonProfiledSize	ulong: bytes	122909338
profiledSize	ulong: bytes	122909338
reservedSize	ulong: bytes	251658240
reservedTopAddress	ulong: address	5486149632
startAddress	ulong: address	5234491392
startTime	long: millis	75476045500

expansionSize	ulong: bytes	65536
initialSize	ulong: bytes	2555904
minBlockLength	ulong: bytes	6
nonNMethodSize	ulong: bytes	5839564
nonProfiledSize	ulong: bytes	122909338
profiledSize	ulong: bytes	122909338
reservedSize	ulong: bytes	251658240
reservedTopAddress	ulong: address	4775477248
startAddress	ulong: address	4523819008
startTime	long: millis	46914774292

expansionSize	ulong: bytes	65536
initialSize	ulong: bytes	2555904
minBlockLength	ulong: bytes	6
nonNMethodSize	ulong: bytes	5839564
nonProfiledSize	ulong: bytes	122909338
profiledSize	ulong: bytes	122909338
reservedSize	ulong: bytes	251658240
reservedTopAddress	ulong: address	4778721280
startAddress	ulong: address	4527063040
startTime	long: millis	48589449083

JVM: Compiler

JITRestart

default profiling startTime eventThread 17 21 22

Category: Java Virtual Machine / Compiler

Restart of the JIT compilers after they were stopped

Configuration	enabled
default	true
profiling	true

Field	Type	Description
freedMemory	ulong: bytes	Freed Memory
codeCacheMaxCapacity	ulong: bytes	Code Cache Maximum Capacity

Compilation

default profiling startTime duration eventThread 11 17 21 22

Category: Java Virtual Machine / Compiler

Results of method compilation attempts

Configuration	enabled	threshold
default	true	1000 ms
profiling	true	100 ms

Field	Type	Description
compileId	int	Compilation Identifier
compiler	CompilerType 14+	Compiler Consider contributing a description to jfreventcollector.
method	Method	Method Consider contributing a description to jfreventcollector.
compileLevel	ushort	Compilation Level
succeded	boolean	Succeeded
isOsr	boolean	On Stack Replacement
codeSize	ulong: bytes	Compiled Code Size
inlinedBytes	ulong: bytes	Inlined Code Size

Examples 3

codeSize	ulong: bytes	7040
compileId	int	14402
compileLevel	ushort	3
compiler	CompilerType	c1
inlinedBytes	ulong: bytes	123
isOsr	boolean	false
method	Method
descriptor	string	(Lcom/twitter/finagle/http/Request;Lcom/twitter/finagle/Service;)Lcom/twitter/util/Future;
hidden	boolean	false
modifiers	int	1
name	string	apply
type	Class
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
hidden	boolean	false
modifiers	int	49
name	string	com/twitter/finagle/http/filter/HttpNackFilter
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
location	string	null
name	string	null
version	string	null
name	string	com/twitter/finagle/http/filter
startTime	long: millis	52637788584
succeded	boolean	true

codeSize	ulong: bytes	4728
compileId	int	4965
compileLevel	ushort	4
compiler	CompilerType	c2
inlinedBytes	ulong: bytes	0
isOsr	boolean	false
method	Method
descriptor	string	()I
hidden	boolean	false
modifiers	int	0
name	string	readLine
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	java/util/Properties$LineReader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util
startTime	long: millis	5978525083
succeded	boolean	true

codeSize	ulong: bytes	38768
compileId	int	8071
compileLevel	ushort	4
compiler	CompilerType	c2
inlinedBytes	ulong: bytes	6045
isOsr	boolean	false
method	Method
descriptor	string	(Lcafesat/asts/core/Trees$Formula;Lscala/collection/mutable/ListBuffer;Lscala/runtime/ObjectRef;Lscala/runtime/LazyRef;)I
hidden	boolean	false
modifiers	int	18
name	string	rec$1
type	Class
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
hidden	boolean	false
modifiers	int	49
name	string	cafesat/sat/ConjunctiveNormalForm$
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
location	string	null
name	string	null
version	string	null
name	string	cafesat/sat
startTime	long: millis	78091594041
succeded	boolean	true

CompilerPhase

default profiling startTime duration eventThread 11 17 21 22

Category: Java Virtual Machine / Compiler

Describes various phases of the compilation process like inlining or string optimization related phases

Configuration	enabled	threshold
default	true	60 s
profiling	true	10 s

Field	Type	Description
phase	CompilerPhaseType	Compile Phase
compileId	int	Compilation Identifier
phaseLevel	ushort	Phase Level

CompilationFailure

profiling startTime eventThread 11 17 21 22

Category: Java Virtual Machine / Compiler

In case a JIT compilation failed, a compilation failure is triggered, reporting the reason

Configuration	enabled
default	false
profiling	true

Field	Type	Description
failureMessage	string	Failure Message
compileId	int	Compilation Identifier

Examples 3

compileId	int	6317
failureMessage	string	out of virtual registers in LIR generator
startTime	long: millis	29774204541

compileId	int	23506
failureMessage	string	concurrent class loading
startTime	long: millis	98563910709

compileId	int	5061
failureMessage	string	concurrent class loading
startTime	long: millis	5977357375

CompilerInlining

startTime eventThread 11 17 21 22

Category: Java Virtual Machine / Compiler / Optimization

Describes the result of a method inlining attempt

Configuration	enabled
default	false
profiling	false

Field	Type	Description
compileId	int	Compilation Identifier
caller	Method	Caller Method
callee	CalleeMethod struct	Callee Method
succeeded	boolean	Succeeded
message	string	Message
bci	int	Bytecode Index

Examples 3

bci	int	47
callee	CalleeMethod
descriptor	string	()B
name	string	coder
type	string	java/lang/String
caller	Method
descriptor	string	(Ljava/lang/String;I)Z
hidden	boolean	false
modifiers	int	1
name	string	startsWith
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	49
name	string	java/lang/String
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
compileId	int	1485
message	string	inline
startTime	long: millis	479413459
succeeded	boolean	true

bci	int	1
callee	CalleeMethod
descriptor	string	()V
name	string	<init>
type	string	java/lang/Object
caller	Method
descriptor	string	()V
hidden	boolean	false
modifiers	int	4
name	string	<init>
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	1057
name	string	java/util/AbstractCollection
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util
compileId	int	1449
message	string	inline
startTime	long: millis	687632500
succeeded	boolean	true

bci	int	1
callee	CalleeMethod
descriptor	string	()V
name	string	<init>
type	string	java/lang/Object
caller	Method
descriptor	string	()V
hidden	boolean	false
modifiers	int	4
name	string	<init>
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	1057
name	string	java/util/AbstractCollection
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util
compileId	int	1466
message	string	inline
startTime	long: millis	339052458
succeeded	boolean	true

Deoptimization

default profiling startTime eventThread stackTrace 14 17 21 22

Category: Java Virtual Machine / Compiler

Describes the detection of an uncommon situation in a compiled method which may lead to deoptimization of the method

Configuration	enabled	stackTrace
default	true	false
profiling	true	true

Field	Type	Description
compileId	int	Compilation Identifier
compiler	CompilerType	Compiler Consider contributing a description to jfreventcollector.
method	Method	Method Consider contributing a description to jfreventcollector.
lineNumber	int	Line Number
bci	int	Bytecode Index
instruction	Bytecode	Instruction Consider contributing a description to jfreventcollector.
reason	DeoptimizationReason	Reason Consider contributing a description to jfreventcollector.
action	DeoptimizationAction	Action Consider contributing a description to jfreventcollector.

Examples 3

action	DeoptimizationAction	maybe_recompile
bci	int	51
compileId	int	2538
compiler	CompilerType	c2
instruction	Bytecode	invokevirtual
lineNumber	int	1380
method	Method
descriptor	string	(Ljava/lang/Class;I)Ljava/lang/Object;
hidden	boolean	false
modifiers	int	1
name	string	allocateUninitializedArray
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	49
name	string	jdk/internal/misc/Unsafe
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	jdk/internal/misc
reason	DeoptimizationReason	class_check
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	51
lineNumber	int	1380
method	Method
descriptor	string	(Ljava/lang/Class;I)Ljava/lang/Object;
hidden	boolean	false
modifiers	int	1
name	string	allocateUninitializedArray
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	49
name	string	jdk/internal/misc/Unsafe
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	jdk/internal/misc
type	FrameType	JIT compiled
		…
truncated	boolean	false
startTime	long: millis	1032675792

action	DeoptimizationAction	reinterpret
bci	int	4
compileId	int	1465
compiler	CompilerType	c2
instruction	Bytecode	ifne
lineNumber	int	78
method	Method
descriptor	string	(I)Ljava/lang/CharacterData;
hidden	boolean	false
modifiers	int	24
name	string	of
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	1056
name	string	java/lang/CharacterData
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
reason	DeoptimizationReason	unstable_if
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	4
lineNumber	int	78
method	Method
descriptor	string	(I)Ljava/lang/CharacterData;
hidden	boolean	false
modifiers	int	24
name	string	of
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	1056
name	string	java/lang/CharacterData
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
type	FrameType	JIT compiled
		…
truncated	boolean	false
startTime	long: millis	377122833

action	DeoptimizationAction	maybe_recompile
bci	int	19
compileId	int	3436
compiler	CompilerType	c2
instruction	Bytecode	if_icmpge
lineNumber	int	285
method	Method
descriptor	string	(Ljava/nio/ByteBuffer;ILjava/lang/String;I)I
hidden	boolean	false
modifiers	int	8
name	string	stringFromByteBufferMatches
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	jdk/internal/jimage/ImageStringsReader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	jdk/internal/jimage
reason	DeoptimizationReason	profile_predicate
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	19
lineNumber	int	285
method	Method
descriptor	string	(Ljava/nio/ByteBuffer;ILjava/lang/String;I)I
hidden	boolean	false
modifiers	int	8
name	string	stringFromByteBufferMatches
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	jdk/internal/jimage/ImageStringsReader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	jdk/internal/jimage
type	FrameType	Inlined
		…
truncated	boolean	false
startTime	long: millis	4128942541

CompilerStatistics

default profiling startTime every chunk 11 17 21 22

Category: Java Virtual Machine / Compiler

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	1000 ms
profiling	true	1000 ms

Field	Type	Description
compileCount	int	Compiled Methods
bailoutCount	int	Bailouts
invalidatedCount	int	Invalidated Compilations
osrCompileCount	int	OSR Compilations
standardCompileCount	int	Standard Compilations
osrBytesCompiled	ulong: bytes	OSR Bytes Compiled
standardBytesCompiled	ulong: bytes	Standard Bytes Compiled
nmethodsSize	ulong: bytes	Compilation Resulting Size
nmethodCodeSize	ulong: bytes	Compilation Resulting Code Size
peakTimeSpent	long: millis	Peak Time
totalTimeSpent	long: millis	Total time

Examples 3

bailoutCount	int	4
compileCount	int	8034
invalidatedCount	int	0
nmethodCodeSize	ulong: bytes	10128120
nmethodsSize	ulong: bytes	15424704
osrBytesCompiled	ulong: bytes	0
osrCompileCount	int	89
peakTimeSpent	long: millis	4774
standardBytesCompiled	ulong: bytes	0
standardCompileCount	int	7945
startTime	long: millis	83761774208
totalTimeSpent	long: millis	54299

bailoutCount	int	6
compileCount	int	23625
invalidatedCount	int	0
nmethodCodeSize	ulong: bytes	30925584
nmethodsSize	ulong: bytes	47172856
osrBytesCompiled	ulong: bytes	0
osrCompileCount	int	181
peakTimeSpent	long: millis	1068
standardBytesCompiled	ulong: bytes	0
standardCompileCount	int	23444
startTime	long: millis	82109837625
totalTimeSpent	long: millis	51632

bailoutCount	int	2
compileCount	int	7782
invalidatedCount	int	0
nmethodCodeSize	ulong: bytes	9358800
nmethodsSize	ulong: bytes	14780720
osrBytesCompiled	ulong: bytes	0
osrCompileCount	int	66
peakTimeSpent	long: millis	1043
standardBytesCompiled	ulong: bytes	0
standardCompileCount	int	7716
startTime	long: millis	32415498042
totalTimeSpent	long: millis	20578

CompilerConfiguration

default profiling startTime end chunk 11 17 21 22

Category: Java Virtual Machine / Compiler

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
threadCount	int	Thread Count
tieredCompilation	boolean	Tiered Compilation
dynamicCompilerThreadCount	boolean 20+	Uses Dynamic Number of Compiler Threads

Examples 3

dynamicCompilerThreadCount	boolean	true
startTime	long: millis	14190149791
threadCount	int	4
tieredCompilation	boolean	true

dynamicCompilerThreadCount	boolean	true
startTime	long: millis	20956119292
threadCount	int	4
tieredCompilation	boolean	true

dynamicCompilerThreadCount	boolean	true
startTime	long: millis	117193287416
threadCount	int	4
tieredCompilation	boolean	true

JVM: Diagnostics

SyncOnValueBasedClass

experimental default profiling startTime eventThread stackTrace 16 17 21 22

Category: Java Virtual Machine / Diagnostics

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	stackTrace
default	true	true
profiling	true	true

Field	Type	Description
valueBasedClass	Class	Value Based Class Consider contributing a description to jfreventcollector.

HeapDump

default profiling startTime duration eventThread stackTrace 15 17 21 22

Category: Java Virtual Machine / Diagnostics

Information about a successfully written Java heap dump

Configuration	enabled	stackTrace	threshold
default	true	true	0 ns
profiling	true	true	0 ns

Field	Type	Description
destination	string	Destination Path of the Dump
size	long	Size
gcBeforeDump	boolean	GC Before Dump
onOutOfMemoryError	boolean	Heap Dump on Out of Memory Error
overwrite	boolean 21+	Overwrite Heap dump overwrites previous file location if it exists
compression	int 21+	Compression Level Compression level of the dump, if larger than 0 we use gzip compression with this level

JavaAgent

default profiling startTime end chunk 21 22

Category: Java Virtual Machine / Diagnostics

A Java programming language agent making use of the java.lang.instrument package for instrumenting programs running on the JVM

Configuration	enabled	period
default	true	endChunk
profiling	true	endChunk

Field	Type	Description
name	string	Name
options	string	Options
dynamic	boolean	Dynamic If the agent attached to the JVM dynamically during runtime, i.e. not at startup
initializationTime	Ticks	Initialization Time The time the JVM initialized the agent
initializationDuration	Tickspan	Initialization Duration The duration of executing the initialization method, either premain or agentmain

NativeAgent

default profiling startTime end chunk 21 22

Category: Java Virtual Machine / Diagnostics

A native programming language agent making use of the JVMTI interface used by development, profiling and monitoring tools

Configuration	enabled	period
default	true	endChunk
profiling	true	endChunk

Field	Type	Description
name	string	Name
options	string	Options
dynamic	boolean	Dynamic If the library attached to the JVM dynamically during runtime, i.e. not at startup
initializationTime	Ticks	Initialization Time The time the JVM initialized the agent
initializationDuration	Tickspan	Initialization Duration The duration of executing the JVMTI VMInit event callback. If no VMInit callback is specified, the duration is 0. For a dynamically loaded agent, it is the duration of executing the call to Agent_OnAttach.
path	string	Path The path of the library

JVM: Flag

IntFlagChanged

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
name	string	Name
oldValue	int	Old Value
newValue	int	New Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

UnsignedIntFlagChanged

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
name	string	Name
oldValue	uint	Old Value
newValue	uint	New Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

LongFlagChanged

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
name	string	Name
oldValue	long	Old Value
newValue	long	New Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

UnsignedLongFlagChanged

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
name	string	Name
oldValue	ulong	Old Value
newValue	ulong	New Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

DoubleFlagChanged

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
name	string	Name
oldValue	double	Old Value
newValue	double	New Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

BooleanFlagChanged

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
name	string	Name
oldValue	boolean	Old Value
newValue	boolean	New Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

StringFlagChanged

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
name	string	Name
oldValue	string	Old Value
newValue	string	New Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

IntFlag

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
name	string	Name
value	int	Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

Examples 3

name	string	JavaPriority2_To_OSPriority
origin	FlagValueOrigin	Default
startTime	long: millis	46914777209
value	int	-1

name	string	ThreadPriorityPolicy
origin	FlagValueOrigin	Default
startTime	long: millis	689924375
value	int	0

name	string	ObjectAlignmentInBytes
origin	FlagValueOrigin	Default
startTime	long: millis	28294044708
value	int	8

UnsignedIntFlag

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
name	string	Name
value	uint	Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

Examples 3

name	string	MarkSweepAlwaysCompactCount
origin	FlagValueOrigin	Default
startTime	long: millis	101284454042
value	uint	4

name	string	G1RefProcDrainInterval
origin	FlagValueOrigin	Default
startTime	long: millis	135014006416
value	uint	1000

name	string	ConcGCThreads
origin	FlagValueOrigin	Default
startTime	long: millis	28294051291
value	uint	0

LongFlag

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
name	string	Name
value	long	Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

Examples 3

name	string	LoopMaxUnroll
origin	FlagValueOrigin	Default
startTime	long: millis	340862500
value	long	16

name	string	InterpreterProfilePercentage
origin	FlagValueOrigin	Default
startTime	long: millis	689940958
value	long	33

name	string	TieredRateUpdateMaxTime
origin	FlagValueOrigin	Default
startTime	long: millis	482150334
value	long	25

UnsignedLongFlag

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
name	string	Name
value	ulong	Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

Examples 3

name	string	LargePageHeapSizeThreshold
origin	FlagValueOrigin	Default
startTime	long: millis	482166750
value	ulong	134217728

name	string	MetadataAllocationFailALotInterval
origin	FlagValueOrigin	Default
startTime	long: millis	340879541
value	ulong	1000

name	string	TLABRefillWasteFraction
origin	FlagValueOrigin	Default
startTime	long: millis	689956208
value	ulong	64

DoubleFlag

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
name	string	Name
value	double	Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

Examples 3

name	string	G1PeriodicGCSystemLoadThreshold
origin	FlagValueOrigin	Default
startTime	long: millis	82931781125
value	double	0.0

name	string	G1PeriodicGCSystemLoadThreshold
origin	FlagValueOrigin	Default
startTime	long: millis	101284488959
value	double	0.0

name	string	ZCollectionIntervalMajor
origin	FlagValueOrigin	Default
startTime	long: millis	43601228416
value	double	-1.0

BooleanFlag

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
name	string	Name
value	boolean	Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

Examples 3

name	string	PatchALot
origin	FlagValueOrigin	Default
startTime	long: millis	340898583
value	boolean	false

name	string	UseFastNewObjectArray
origin	FlagValueOrigin	Default
startTime	long: millis	689971541
value	boolean	true

name	string	UseSIMDForBigIntegerShiftIntrinsics
origin	FlagValueOrigin	Default
startTime	long: millis	482184625
value	boolean	true

StringFlag

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / Flag

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
name	string	Name
value	string	Value
origin	FlagValueOrigin	Origin Consider contributing a description to jfreventcollector.

Examples 3

name	string	DumpLoadedClassList
origin	FlagValueOrigin	Default
startTime	long: millis	14190249833
value	string	null

name	string	DumpLoadedClassList
origin	FlagValueOrigin	Default
startTime	long: millis	690006958
value	string	null

name	string	PrintIdealGraphAddress
origin	FlagValueOrigin	Default
startTime	long: millis	20956800084
value	string	127.0.0.1

JVM: GC: Collector

GarbageCollection

default profiling startTime duration eventThread 11 17 21 22

Category: Java Virtual Machine / GC / Collector

Garbage collection performed by the JVM

Configuration	enabled	threshold
default	true	0 ms
profiling	true	0 ms

Field	Type	Description
gcId	uint	GC Identifier
name	GCName	Name The name of the Garbage Collector
cause	GCCause	Cause The reason for triggering this Garbage Collection
sumOfPauses	Tickspan	Sum of Pauses Sum of all the times in which Java execution was paused during the garbage collection
longestPause	Tickspan	Longest Pause Longest individual pause during the garbage collection

Examples 3

cause	GCCause	G1 Evacuation Pause
gcId	uint	12
longestPause	Tickspan	4686625
name	GCName	G1New
startTime	long: millis	1416420791
sumOfPauses	Tickspan	4686625

cause	GCCause	Metadata GC Threshold
gcId	uint	1
longestPause	Tickspan	14376625
name	GCName	SerialOld
startTime	long: millis	693402041
sumOfPauses	Tickspan	14376625

cause	GCCause	Allocation Failure
gcId	uint	37
longestPause	Tickspan	221258375
name	GCName	ParallelScavenge
startTime	long: millis	30169596125
sumOfPauses	Tickspan	221258375

SystemGC

default profiling startTime duration eventThread stackTrace 17 21 22

Category: Java Virtual Machine / GC / Collector

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	stackTrace	threshold
default	true	true	0 ms
profiling	true	true	0 ms

Field	Type	Description
invokedConcurrent	boolean	Invoked Concurrent

Examples 3

invokedConcurrent	boolean	false
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	0
lineNumber	int	-1
method	Method
descriptor	string	()V
hidden	boolean	false
modifiers	int	257
name	string	gc
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/lang/Runtime
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
type	FrameType	Native
		…
truncated	boolean	false
startTime	long: millis	1054362208

invokedConcurrent	boolean	false
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	0
lineNumber	int	-1
method	Method
descriptor	string	()V
hidden	boolean	false
modifiers	int	257
name	string	gc
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/lang/Runtime
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
type	FrameType	Native
		…
truncated	boolean	false
startTime	long: millis	89406320667

invokedConcurrent	boolean	false
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	0
lineNumber	int	-1
method	Method
descriptor	string	()V
hidden	boolean	false
modifiers	int	257
name	string	gc
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/lang/Runtime
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
type	FrameType	Native
		…
truncated	boolean	false
startTime	long: millis	1753256291

ParallelOldGarbageCollection

default profiling startTime duration 11 17 21 22

Category: Java Virtual Machine / GC / Collector

Appearing in: ParallelGC

Missing in: G1GC, SerialGC, ShenandoahGC, ZGC

Extra information specific to Parallel Old Garbage Collections

Configuration	enabled	threshold
default	true	0 ms
profiling	true	0 ms

Field	Type	Description
gcId	uint	GC Identifier
densePrefix	ulong: address	Dense Prefix The address of the dense prefix, used when compacting

Examples 1

ParallelGC

densePrefix	ulong: address	30155997184
gcId	uint	75
startTime	long: millis	79123446292

YoungGarbageCollection

default profiling startTime duration 11 17 21 22

Category: Java Virtual Machine / GC / Collector

Appearing in: G1GC, ParallelGC, SerialGC

Missing in: ShenandoahGC, ZGC

Extra information specific to Young Garbage Collections

Configuration	enabled	threshold
default	true	0 ms
profiling	true	0 ms

Field	Type	Description
gcId	uint	GC Identifier
tenuringThreshold	uint	Tenuring Threshold

Examples 3

gcId	uint	105
startTime	long: millis	97312798542
tenuringThreshold	uint	15

gcId	uint	71
startTime	long: millis	7944134375
tenuringThreshold	uint	1

gcId	uint	3
startTime	long: millis	930384000
tenuringThreshold	uint	1

OldGarbageCollection

default profiling startTime duration 11 17 21 22

Category: Java Virtual Machine / GC / Collector

Appearing in: G1GC, ParallelGC, SerialGC

Missing in: ShenandoahGC, ZGC

Extra information specific to Old Garbage Collections

Configuration	enabled	threshold
default	true	0 ms
profiling	true	0 ms

Field	Type	Description
gcId	uint	GC Identifier

Examples 3

gcId	uint	9
startTime	long: millis	1450494417

gcId	uint	54
startTime	long: millis	43628069916

gcId	uint	1
startTime	long: millis	693402041

G1GarbageCollection

default profiling startTime duration 11 17 21 22

Category: Java Virtual Machine / GC / Collector

Appearing in: G1GC

Missing in: ParallelGC, SerialGC, ShenandoahGC, ZGC

Extra information specific to G1 Young Garbage Collections

Configuration	enabled	threshold
default	true	0 ms
profiling	true	0 ms

Field	Type	Description
gcId	uint	GC Identifier
type	G1YCType	Type Consider contributing a description to jfreventcollector.

Examples 1

G1GC

gcId	uint	4
startTime	long: millis	950666083
type	G1YCType	Normal

ZYoungGarbageCollection

default profiling startTime duration eventThread 21 22

Category: Java Virtual Machine / GC / Collector

Extra information specific to ZGC Young Garbage Collections

Configuration	enabled	threshold
default	true	0 ms
profiling	true	0 ms

Field	Type	Description
gcId	uint	GC Identifier
tenuringThreshold	uint	Tenuring Threshold

ZOldGarbageCollection

default profiling startTime duration eventThread 21 22

Category: Java Virtual Machine / GC / Collector

Extra information specific to ZGC Old Garbage Collections

Configuration	enabled	threshold
default	true	0 ms
profiling	true	0 ms

Field	Type	Description
gcId	uint	GC Identifier

JVM: GC: Configuration

GCConfiguration

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / GC / Configuration

The configuration of the garbage collector

Configuration	enabled	period
default	true	everyChunk
profiling	true	everyChunk

Field	Type	Description
youngCollector	GCName	Young Garbage Collector The garbage collector used for the young generation
oldCollector	GCName	Old Garbage Collector The garbage collector used for the old generation
parallelGCThreads	uint	Parallel GC Threads Number of parallel threads to use for garbage collection
concurrentGCThreads	uint	Concurrent GC Threads Number of concurrent threads to use for garbage collection
usesDynamicGCThreads	boolean	Uses Dynamic GC Threads Whether a dynamic number of GC threads are used or not
isExplicitGCConcurrent	boolean	Concurrent Explicit GC Whether System.gc() is concurrent or not
isExplicitGCDisabled	boolean	Disabled Explicit GC Whether System.gc() will cause a garbage collection or not
pauseTarget	long: millis	Pause Target Target for GC pauses
gcTimeRatio	uint	GC Time Ratio Target for runtime vs garbage collection time

Examples 3

concurrentGCThreads	uint	0
gcTimeRatio	uint	99
isExplicitGCConcurrent	boolean	false
isExplicitGCDisabled	boolean	false
oldCollector	GCName	SerialOld
parallelGCThreads	uint	0
pauseTarget	long: millis	-9223372036854775808
startTime	long: millis	100110830083
usesDynamicGCThreads	boolean	true
youngCollector	GCName	DefNew

concurrentGCThreads	uint	2
gcTimeRatio	uint	12
isExplicitGCConcurrent	boolean	false
isExplicitGCDisabled	boolean	false
oldCollector	GCName	G1Old
parallelGCThreads	uint	8
pauseTarget	long: millis	-9223372036854775808
startTime	long: millis	117267336166
usesDynamicGCThreads	boolean	true
youngCollector	GCName	G1New

concurrentGCThreads	uint	0
gcTimeRatio	uint	99
isExplicitGCConcurrent	boolean	false
isExplicitGCDisabled	boolean	false
oldCollector	GCName	ParallelOld
parallelGCThreads	uint	8
pauseTarget	long: millis	-9223372036854775808
startTime	long: millis	99012180792
usesDynamicGCThreads	boolean	true
youngCollector	GCName	ParallelScavenge

GCSurvivorConfiguration

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / GC / Configuration

The configuration of the survivors of garbage collection

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
maxTenuringThreshold	ubyte	Maximum Tenuring Threshold Upper limit for the age of how old objects to keep in the survivor area
initialTenuringThreshold	ubyte	Initial Tenuring Threshold Initial age limit for how old objects to keep in survivor area

Examples 3

initialTenuringThreshold	ubyte	7
maxTenuringThreshold	ubyte	15
startTime	long: millis	117267337291

initialTenuringThreshold	ubyte	7
maxTenuringThreshold	ubyte	15
startTime	long: millis	14613397750

initialTenuringThreshold	ubyte	7
maxTenuringThreshold	ubyte	15
startTime	long: millis	108530487125

GCTLABConfiguration

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / GC / Configuration

The configuration of the Thread Local Allocation Buffers (TLABs)

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
usesTLABs	boolean	TLABs Used If Thread Local Allocation Buffers (TLABs) are in use
minTLABSize	ulong: bytes	Minimum TLAB Size
tlabRefillWasteLimit	ulong: bytes	TLAB Refill Waste Limit

Examples 3

minTLABSize	ulong: bytes	2048
startTime	long: millis	108530488542
tlabRefillWasteLimit	ulong: bytes	64
usesTLABs	boolean	true

minTLABSize	ulong: bytes	2048
startTime	long: millis	698262208
tlabRefillWasteLimit	ulong: bytes	64
usesTLABs	boolean	true

minTLABSize	ulong: bytes	2048
startTime	long: millis	38672883750
tlabRefillWasteLimit	ulong: bytes	64
usesTLABs	boolean	true

GCHeapConfiguration

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / GC / Configuration

The configuration of the garbage collected heap

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
minSize	ulong: bytes	Minimum Heap Size
maxSize	ulong: bytes	Maximum Heap Size
initialSize	ulong: bytes	Initial Heap Size
usesCompressedOops	boolean	If Compressed Oops Are Used If compressed Oops (Ordinary Object Pointers) are enabled
compressedOopsMode	NarrowOopMode	Compressed Oops Mode The kind of compressed oops being used
objectAlignment	ulong: bytes	Object Alignment Object alignment (in bytes) on the heap
heapAddressBits	ubyte	Heap Address Size Heap Address Size (in bits)

Examples 3

compressedOopsMode	NarrowOopMode	Zero based
heapAddressBits	ubyte	32
initialSize	ulong: bytes	268435456
maxSize	ulong: bytes	4294967296
minSize	ulong: bytes	8388608
objectAlignment	ulong: bytes	8
startTime	long: millis	698263208
usesCompressedOops	boolean	true

compressedOopsMode	NarrowOopMode	Zero based
heapAddressBits	ubyte	32
initialSize	ulong: bytes	268435456
maxSize	ulong: bytes	4294967296
minSize	ulong: bytes	8388608
objectAlignment	ulong: bytes	8
startTime	long: millis	14613399166
usesCompressedOops	boolean	true

compressedOopsMode	NarrowOopMode	Zero based
heapAddressBits	ubyte	32
initialSize	ulong: bytes	268435456
maxSize	ulong: bytes	4294967296
minSize	ulong: bytes	8388608
objectAlignment	ulong: bytes	8
startTime	long: millis	496231084
usesCompressedOops	boolean	true

YoungGenerationConfiguration

default profiling startTime duration end chunk 11 17 21 22

Category: Java Virtual Machine / GC / Configuration

The configuration of the young generation of the garbage collected heap

Configuration	enabled	period
default	true	beginChunk
profiling	true	beginChunk

Field	Type	Description
minSize	ulong: bytes	Minimum Young Generation Size
maxSize	ulong: bytes	Maximum Young Generation Size
newRatio	uint	New Ratio The size of the young generation relative to the tenured generation

Examples 3

maxSize	ulong: bytes	2575302656
minSize	ulong: bytes	1363144
newRatio	uint	2
startTime	long: millis	196524385083

maxSize	ulong: bytes	1431633920
minSize	ulong: bytes	89456640
newRatio	uint	2
startTime	long: millis	97864789666

maxSize	ulong: bytes	1431306240
minSize	ulong: bytes	89128960
newRatio	uint	2
startTime	long: millis	496238042

JVM: GC: Detailed

ZThreadDebug

internal startTime duration eventThread 18 21 22

Category: Java Virtual Machine / GC / Detailed

Temporary latency measurements used during development and debugging of ZGC

Only valid for the ZGC.

Field	Type	Description
gcId	uint	GC Identifier
name	string	Name The name of the GC runner

G1MMU

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC

Missing in: ParallelGC, SerialGC, ShenandoahGC, ZGC

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
gcId	uint	GC Identifier
timeSlice	long: millis	Time Slice Time slice used to calculate MMU
gcTime	long: millis	GC Time Time stopped because of GC during last time slice
pauseTarget	long: millis	Pause Target Max time allowed to be spent on GC during last time slice

Examples 1

G1GC

gcId	uint	82
gcTime	long: millis	102
pauseTarget	long: millis	200
startTime	long: millis	63559704750
timeSlice	long: millis	201

EvacuationInformation

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC

Missing in: ParallelGC, SerialGC, ShenandoahGC, ZGC

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
gcId	uint	GC Identifier
cSetRegions	uint	Collection Set Regions
cSetUsedBefore	ulong: bytes	Collection Set Before Memory usage before GC in the collection set regions
cSetUsedAfter	ulong: bytes	Collection Set After Memory usage after GC in the collection set regions
allocationRegions	uint	Allocation Regions Regions chosen as allocation regions during evacuation (includes survivors and old space regions)
allocationRegionsUsedBefore	ulong: bytes	Allocation Regions Before Memory usage before GC in allocation regions
allocationRegionsUsedAfter	ulong: bytes	Allocation Regions After Memory usage after GC in allocation regions
bytesCopied	ulong: bytes	Bytes Copied
regionsFreed	uint	Regions Freed

Examples 1

G1GC

allocationRegions	uint	22
allocationRegionsUsedAfter	ulong: bytes	46137344
allocationRegionsUsedBefore	ulong: bytes	1048576
bytesCopied	ulong: bytes	45088768
cSetRegions	uint	34
cSetUsedAfter	ulong: bytes	0
cSetUsedBefore	ulong: bytes	71303168
gcId	uint	41
regionsFreed	uint	34
startTime	long: millis	29381136750

ObjectCountAfterGC

startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC, ParallelGC, SerialGC

Missing in: ShenandoahGC, ZGC

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	false
profiling	false

Field	Type	Description
gcId	uint	GC Identifier
objectClass	Class	Object Class Consider contributing a description to jfreventcollector.
count	long	Count
totalSize	ulong: bytes	Total Size

Examples 3

count	long	96
gcId	uint	1
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	0
name	string	[Ljava/util/concurrent/ConcurrentHashMap$Node;
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util/concurrent
startTime	long: millis	702041958
totalSize	ulong: bytes	318272

count	long	6731
gcId	uint	17
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/LinkedHashMap
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util
startTime	long: millis	1617457750
totalSize	ulong: bytes	430784

count	long	292085
gcId	uint	22
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	java/util/HashMap$Node
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util
startTime	long: millis	13696186625
totalSize	ulong: bytes	9346720

G1EvacuationYoungStatistics

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC

Missing in: ParallelGC, SerialGC, ShenandoahGC, ZGC

Memory related evacuation statistics during GC for the young generation

Configuration	enabled
default	true
profiling	true

Field	Type	Description
statistics	G1EvacuationStatistics struct	Evacuation Statistics

Examples 1

G1GC

startTime	long: millis	36822423375
statistics	G1EvacuationStatistics
allocated	ulong: bytes	23068672
directAllocated	ulong: bytes	0
failureUsed	ulong: bytes	0
failureWaste	ulong: bytes	0
gcId	uint	49
numDirectAllocated	ulong	5
numPlabsFilled	ulong	2193956712555703988
regionEndWaste	ulong: bytes	0
regionsRefilled	uint	11
undoWaste	ulong: bytes	0
used	ulong: bytes	23067416
wasted	ulong: bytes	1256

G1EvacuationOldStatistics

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC

Missing in: ParallelGC, SerialGC, ShenandoahGC, ZGC

Memory related evacuation statistics during GC for the old generation

Configuration	enabled
default	true
profiling	true

Field	Type	Description
statistics	G1EvacuationStatistics struct	Evacuation Statistics

Examples 1

G1GC

startTime	long: millis	58319847791
statistics	G1EvacuationStatistics
allocated	ulong: bytes	58216008
directAllocated	ulong: bytes	0
failureUsed	ulong: bytes	0
failureWaste	ulong: bytes	0
gcId	uint	75
numDirectAllocated	ulong	6184184024
numPlabsFilled	ulong	0
regionEndWaste	ulong: bytes	0
regionsRefilled	uint	28
undoWaste	ulong: bytes	0
used	ulong: bytes	56031472
wasted	ulong: bytes	2032

G1BasicIHOP

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC

Missing in: ParallelGC, SerialGC, ShenandoahGC, ZGC

Basic statistics related to current IHOP calculation

Configuration	enabled
default	true
profiling	true

Field	Type	Description
gcId	uint	GC Identifier
threshold	ulong: bytes	Current IHOP Threshold Current IHOP threshold
thresholdPercentage	float: percentage	Current IHOP Threshold Current IHOP threshold in percent of old generation
targetOccupancy	ulong: bytes	Target Occupancy Target old generation occupancy to reach at the start of mixed GC
currentOccupancy	ulong: bytes	Current Occupancy Current old generation occupancy
recentMutatorAllocationSize	ulong: bytes	Recent Mutator Allocation Size Mutator allocation during mutator operation in the most recent interval
recentMutatorDuration	long: millis	Recent Mutator Duration Time the mutator ran in the most recent interval
recentAllocationRate	double: bytes-per-second	Recent Allocation Rate Allocation rate of the mutator in the most recent interval in bytes/second
lastMarkingDuration	long: millis	Last Marking Duration Last time from the end of the last concurrent start to the first mixed GC

Examples 1

G1GC

currentOccupancy	ulong: bytes	369087968
gcId	uint	46
lastMarkingDuration	long: millis	4056
recentAllocationRate	double: bytes-per-second	9.574403986410235E7
recentMutatorAllocationSize	ulong: bytes	31844352
recentMutatorDuration	long: millis	332
startTime	long: millis	34612846666
targetOccupancy	ulong: bytes	2006974464
threshold	ulong: bytes	1647272299
thresholdPercentage	float: percentage	0.8207739

G1AdaptiveIHOP

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC

Missing in: ParallelGC, SerialGC, ShenandoahGC, ZGC

Statistics related to current adaptive IHOP calculation

Configuration	enabled
default	true
profiling	true

Field	Type	Description
gcId	uint	GC Identifier
threshold	ulong: bytes	Threshold Current IHOP Threshold
thresholdPercentage	float: percentage	Threshold Current IHOP threshold in percent of the internal target occupancy
ihopTargetOccupancy	ulong: bytes	IHOP Target Occupancy Internal target old generation occupancy to reach at the start of mixed GC
currentOccupancy	ulong: bytes	Current Occupancy Current old generation occupancy
additionalBufferSize	ulong: bytes	Additional Buffer Additional buffer size
predictedAllocationRate	double: bytes-per-second	Predicted Allocation Rate Current predicted allocation rate for the mutator in bytes/second
predictedMarkingDuration	long: millis	Predicted Marking Duration Current predicted time from the end of the last concurrent start to the first mixed GC
predictionActive	boolean	Prediction Active Indicates whether the adaptive IHOP prediction is active

Examples 1

G1GC

additionalBufferSize	ulong: bytes	656408576
currentOccupancy	ulong: bytes	187135592
gcId	uint	114
ihopTargetOccupancy	ulong: bytes	1039977676
predictedAllocationRate	double: bytes-per-second	8.635352805272725E7
predictedMarkingDuration	long: millis	775
predictionActive	boolean	true
startTime	long: millis	94160192958
threshold	ulong: bytes	316619231
thresholdPercentage	float: percentage	0.3044481

PromoteObjectInNewPLAB

profiling startTime eventThread 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC, ParallelGC

Missing in: SerialGC, ShenandoahGC, ZGC

Object survived scavenge and was copied to a new Promotion Local Allocation Buffer (PLAB). Supported GCs are Parallel Scavenge, G1 and CMS with Parallel New. Due to promotion being done in parallel an object might be reported multiple times as the GC threads race to copy all objects.

Configuration	enabled
default	false
profiling	true

Field	Type	Description
gcId	uint	GC Identifier Identifier signifying GC during which the object was promoted
objectClass	Class	Object Class Class of promoted object
objectSize	ulong: bytes	Object Size Size of promoted object
tenuringAge	uint	Object Tenuring Age Tenuring age of a surviving object before being copied. The tenuring age of an object is a value between 0-15 and is incremented each scavenge the object survives. Newly allocated objects have tenuring age 0.
tenured	boolean	Tenured True if object was promoted to Old space, otherwise the object was aged and copied to a Survivor space
plabSize	ulong: bytes	PLAB Size Size of the allocated PLAB to which the object was copied

Examples 2

ParallelGC
G1GC

gcId	uint	5
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	49
name	string	java/lang/String
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
objectSize	ulong: bytes	24
plabSize	ulong: bytes	32752
startTime	long: millis	1224516459
tenured	boolean	false
tenuringAge	uint	1

gcId	uint	7
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/LinkedHashMap
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util
objectSize	ulong: bytes	64
plabSize	ulong: bytes	56672
startTime	long: millis	1208536833
tenured	boolean	false
tenuringAge	uint	0

PromoteObjectOutsidePLAB

profiling startTime eventThread 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC, ParallelGC

Missing in: SerialGC, ShenandoahGC, ZGC

Object survived scavenge and was copied directly to the heap. Supported GCs are Parallel Scavenge, G1 and CMS with Parallel New. Due to promotion being done in parallel an object might be reported multiple times as the GC threads race to copy all objects.

Configuration	enabled
default	false
profiling	true

Field	Type	Description
gcId	uint	GC Identifier Identifier signifying GC during which the object was promoted
objectClass	Class	Object Class Class of promoted object
objectSize	ulong: bytes	Object Size Size of promoted object
tenuringAge	uint	Object Tenuring Age Tenuring age of a surviving object before being copied. The tenuring age of an object is a value between 0-15 and is incremented each scavenge the object survives. Newly allocated objects have tenuring age 0.
tenured	boolean	Tenured True if object was promoted to Old space, otherwise the object was aged and copied to a Survivor space

Examples 2

G1GC
ParallelGC

gcId	uint	7
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	0
name	string	[B
package	Package	null
objectSize	ulong: bytes	51824
startTime	long: millis	1208438125
tenured	boolean	false
tenuringAge	uint	0

gcId	uint	11
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	0
name	string	[Ljava/lang/Object;
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
objectSize	ulong: bytes	16672
startTime	long: millis	2096605667
tenured	boolean	false
tenuringAge	uint	0

PromotionFailed

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Promotion of an object failed

Configuration	enabled
default	true
profiling	true

Field	Type	Description
gcId	uint	GC Identifier
promotionFailed	CopyFailed struct	Promotion Failed Data
thread	Thread	Running thread

EvacuationFailed

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Evacuation of an object failed

Configuration	enabled
default	true
profiling	true

Field	Type	Description
gcId	uint	GC Identifier
evacuationFailed	CopyFailed struct	Evacuation Failed Data

ConcurrentModeFailure

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Concurrent Mode failed

Configuration	enabled
default	true
profiling	true

Field	Type	Description
gcId	uint	GC Identifier

GCCPUTime

default profiling startTime 20 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC, ParallelGC, SerialGC

Missing in: ShenandoahGC, ZGC

GC CPU Time information. Supported: G1GC, ParallelGC and SerialGC

Configuration	enabled
default	true
profiling	true

Field	Type	Description
gcId	uint	GC Identifier
userTime	ulong: nanos	User Time
systemTime	ulong: nanos	System Time
realTime	ulong: nanos	Real Time

Examples 3

gcId	uint	88
realTime	ulong: nanos	0
startTime	long: millis	86914297917
systemTime	ulong: nanos	9999999
userTime	ulong: nanos	30000000

gcId	uint	89
realTime	ulong: nanos	4730000019
startTime	long: millis	74988595625
systemTime	ulong: nanos	1300000000
userTime	ulong: nanos	649999999

gcId	uint	62
realTime	ulong: nanos	39999961
startTime	long: millis	6511144958
systemTime	ulong: nanos	10000000
userTime	ulong: nanos	19999999

AllocationRequiringGC

startTime eventThread stackTrace 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC, ParallelGC, SerialGC

Missing in: ShenandoahGC, ZGC

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	stackTrace
default	false	true
profiling	false	true

Field	Type	Description
gcId	uint	Pending GC Identifier
size	ulong: bytes	Allocation Size

Examples 3

gcId	uint	37
size	ulong: bytes	56
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	51
lineNumber	int	236
method	Method
descriptor	string	(Lakka/actor/ActorRef;Lakka/actor/ActorRef;IIIZ)V
hidden	boolean	false
modifiers	int	1
name	string	<init>
type	Class
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
hidden	boolean	false
modifiers	int	33
name	string	edu/rice/habanero/benchmarks/uct/UctAkkaActorBenchmark$NodeActor
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
location	string	null
name	string	null
version	string	null
name	string	edu/rice/habanero/benchmarks/uct
type	FrameType	Inlined
		…
truncated	boolean	false
startTime	long: millis	30169188334

gcId	uint	79
size	ulong: bytes	32
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	67
lineNumber	int	718
method	Method
descriptor	string	(Lscala/collection/immutable/RedBlackTree$Tree;)Lscala/collection/immutable/RedBlackTree$Tree;
hidden	boolean	false
modifiers	int	1
name	string	blackWithRight
type	Class
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
hidden	boolean	false
modifiers	int	49
name	string	scala/collection/immutable/RedBlackTree$Tree
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	null
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/net/URLClassLoader
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/net
location	string	null
name	string	null
version	string	null
name	string	scala/collection/immutable
type	FrameType	JIT compiled
		…
truncated	boolean	false
startTime	long: millis	10613444208

gcId	uint	56
size	ulong: bytes	2048
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	16
lineNumber	int	2849
method	Method
descriptor	string	(Ljava/lang/Runnable;)V
hidden	boolean	false
modifiers	int	1
name	string	execute
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/concurrent/ForkJoinPool
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util/concurrent
type	FrameType	Inlined
		…
truncated	boolean	false
startTime	long: millis	47266518208

TenuringDistribution

default profiling startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC, SerialGC

Missing in: ParallelGC, ShenandoahGC, ZGC

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled
default	true
profiling	true

Field	Type	Description
gcId	uint	GC Identifier
age	uint	Age
size	ulong: bytes	Size

Examples 2

G1GC
SerialGC

age	uint	11
gcId	uint	14
size	ulong: bytes	0
startTime	long: millis	1540715125

age	uint	14
gcId	uint	5
size	ulong: bytes	0
startTime	long: millis	983426208

G1HeapRegionTypeChange

startTime 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC

Missing in: ParallelGC, SerialGC, ShenandoahGC, ZGC

Information about a G1 heap region type change

Configuration	enabled
default	false
profiling	false

Field	Type	Description
index	uint	Index
from	G1HeapRegionType	From Consider contributing a description to jfreventcollector.
to	G1HeapRegionType	To Consider contributing a description to jfreventcollector.
start	ulong: address	Start
used	ulong: bytes	Used

Examples 1

G1GC

from	G1HeapRegionType	Eden
index	uint	22
start	ulong: address	30110908416
startTime	long: millis	1540666958
to	G1HeapRegionType	Free
used	ulong: bytes	0

ObjectCount

startTime every chunk 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC, ParallelGC, SerialGC

Missing in: ShenandoahGC, ZGC

No additional description available. Write your own and contribute it to jfreventcollector or directly to the OpenJDK.

Configuration	enabled	period
default	false	everyChunk
profiling	false	everyChunk

Field	Type	Description
gcId	uint	GC Identifier
objectClass	Class	Object Class Consider contributing a description to jfreventcollector.
count	long	Count
totalSize	ulong: bytes	Total Size

Examples 3

count	long	1205925
gcId	uint	29
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	49
name	string	java/lang/String
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/lang
startTime	long: millis	9171878750
totalSize	ulong: bytes	28942200

count	long	6731
gcId	uint	1
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/LinkedHashMap
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/java.base
name	string	java.base
version	string	21.0.1
name	string	java/util
startTime	long: millis	702041958
totalSize	ulong: bytes	430784

count	long	1461337
gcId	uint	22
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	0
name	string	[B
package	Package	null
startTime	long: millis	13696186625
totalSize	ulong: bytes	39236960

G1HeapRegionInformation

startTime duration every chunk 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: G1GC

Missing in: ParallelGC, SerialGC, ShenandoahGC, ZGC

Information about a specific heap region in the G1 GC

Configuration	enabled	period
default	false	everyChunk
profiling	false	everyChunk

Field	Type	Description
index	uint	Index
type	G1HeapRegionType	Type Consider contributing a description to jfreventcollector.
start	ulong: address	Start
used	ulong: bytes	Used

Examples