Introduction

The following are the events for the OpenJDK 17 (jdk-17.0.10+4, 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	27303
flushId	ulong	33
size	ulong: bytes	4550687
startTime	long: millis	37692946166

elements	ulong	511
flushId	ulong	66
size	ulong: bytes	236386
startTime	long: millis	70996125667

elements	ulong	124
flushId	ulong	15
size	ulong: bytes	73482
startTime	long: millis	16395623041

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.
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_UseG1GC.jfr
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

destination	string	[...]/code/experiments/jfreventcollector/jfr/sample_UseSerialGC.jfr
flushInterval	long: millis	1000
id	long	1
maxAge	long: millis	9223372036854775807
maxSize	long: bytes	0
name	string	1
recordingDuration	long: millis	9223372036854775807
recordingStart	long: epochmillis	1701099181498
stackTrace	StackTrace	null
startTime	long: millis	339201541

destination	string	[...]/code/experiments/jfreventcollector/jfr/sample_UseParallelGC.jfr
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	98898355625

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	21
name	string	stackTrace
stackTrace	StackTrace	null
startTime	long: millis	479682042
value	string	true

id	long	8
name	string	stackTrace
stackTrace	StackTrace	null
startTime	long: millis	339201541
value	string	true

id	long	55
name	string	enabled
stackTrace	StackTrace	null
startTime	long: millis	688133083
value	string	true

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_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	73752084541

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	108386974667

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

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	sun.boot.library.path
startTime	long: millis	59649638584
value	string	[...]/.sdkman/candidates/java/21.0.1-tem/lib

key	string	java.vm.specification.version
startTime	long: millis	73752102333
value	string	21

key	string	sun.boot.library.path
startTime	long: millis	43552850375
value	string	[...]/.sdkman/candidates/java/21.0.1-tem/lib

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	null
initiatingClassLoader	ClassLoader	null
loadedClass	Class
classLoader	ClassLoader	null
hidden	boolean	true
modifiers	int	48
name	string	java.lang.invoke.LambdaForm$DMH+0x00000008000c5800/1768792843
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/invoke
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	0
lineNumber	int	-1
method	Method
descriptor	string	(Ljava/lang/ClassLoader;Ljava/lang/Class;Ljava/lang/String;[BIILjava/security/ProtectionDomain;ZILjava/lang/Object;)Ljava/lang/Class;
hidden	boolean	false
modifiers	int	264
name	string	defineClass0
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	503602125

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	16433
name	string	java/lang/System$Logger$Level
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
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	9
lineNumber	int	62
method	Method
descriptor	string	()Ljava/lang/System$Logger$Level;
hidden	boolean	false
modifiers	int	8
name	string	getDefaultLevel
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	jdk/internal/logger/SimpleConsoleLogger
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/logger
type	FrameType	Interpreted
		…
truncated	boolean	false
startTime	long: millis	362621083

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	49
name	string	java/util/Formatter
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
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	0
lineNumber	int	4386
method	Method
descriptor	string	(Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/String;
hidden	boolean	false
modifiers	int	137
name	string	format
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
type	FrameType	Interpreted
		…
truncated	boolean	false
startTime	long: millis	714423083

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	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
definingClassLoader	ClassLoader
name	string	bootstrap
type	Class	null
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	361207208

definedClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	1057
name	string	java/util/logging/Handler
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
definingClassLoader	ClassLoader
name	string	bootstrap
type	Class	null
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	711480583

definedClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	48
name	string	sun/util/locale/InternalLocaleBuilder$CaseInsensitiveChar
package	Package
exported	boolean	false
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
definingClassLoader	ClassLoader
name	string	bootstrap
type	Class	null
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	16
lineNumber	int	43
method	Method
descriptor	string	()V
hidden	boolean	false
modifiers	int	8
name	string	<clinit>
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	49
name	string	sun/util/locale/InternalLocaleBuilder
package	Package
exported	boolean	false
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
type	FrameType	Interpreted
		…
truncated	boolean	false
startTime	long: millis	517672334

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	8802273000
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	33
name	string	scala/collection/SeqFactory$Delegate
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

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	4057579000
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	org/slf4j/ILoggerFactory
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/slf4j

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	5904989542
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	33
name	string	org/apache/spark/storage/DefaultTopologyMapper
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/storage

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	2948
fullCount	int	0
methodCount	int	2948
reservedTopAddress	ulong: address	5486149632
startAddress	ulong: address	5363236864
startTime	long: millis	202078282541
unallocatedCapacity	ulong: bytes	118294912

adaptorCount	int	0
codeBlobType	CodeBlobType	CodeHeap 'non-profiled nmethods'
entryCount	int	1688
fullCount	int	0
methodCount	int	1688
reservedTopAddress	ulong: address	4775477248
startAddress	ulong: address	4652564480
startTime	long: millis	20255130334
unallocatedCapacity	ulong: bytes	119340928

adaptorCount	int	730
codeBlobType	CodeBlobType	CodeHeap 'non-nmethods'
entryCount	int	825
fullCount	int	0
methodCount	int	0
reservedTopAddress	ulong: address	4655808512
startAddress	ulong: address	4649959424
startTime	long: millis	96856261208
unallocatedCapacity	ulong: bytes	4263808

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	4778721280
startAddress	ulong: address	4527063040
startTime	long: millis	82931739333

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	20956125292

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	99347691333

JVM: Code Sweeper

SweepCodeCache

default profiling startTime duration eventThread 11 17 until JDK 20

Category: Java Virtual Machine / Code Sweeper

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

Configuration	enabled	threshold
default	true	100 ms
profiling	true	100 ms

Field	Type	Description
sweepId	int	Sweep Identifier
sweptCount	uint	Methods Swept
flushedCount	uint	Methods Flushed
zombifiedCount	uint	Methods Zombified

CodeSweeperStatistics

default profiling startTime every chunk 11 17 until JDK 20

Category: Java Virtual Machine / Code Sweeper

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
sweepCount	int	Sweeps
methodReclaimedCount	int	Methods Reclaimed
totalSweepTime	Tickspan	Time Spent Sweeping
peakFractionTime	Tickspan	Peak Time Fraction Sweep
peakSweepTime	Tickspan	Peak Time Full Sweep

CodeSweeperConfiguration

default profiling startTime end chunk 11 17 until JDK 20

Category: Java Virtual Machine / Code Sweeper

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
sweeperEnabled	boolean	Code Sweeper Enabled
flushingEnabled	boolean	Code Cache Flushing Enabled
sweepThreshold	ulong: bytes 17 until JDK 20	Sweep Threshold

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	int: 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	uint	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	35720
compileId	uint	15861
compileLevel	ushort	4
compiler	CompilerType	c2
inlinedBytes	ulong: bytes	5277
isOsr	boolean	false
method	Method
descriptor	string	(Ljava/lang/Object;)Lio/netty/channel/ChannelHandlerContext;
hidden	boolean	false
modifiers	int	1
name	string	fireUserEventTriggered
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	1056
name	string	io/netty/channel/AbstractChannelHandlerContext
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	io/netty/channel
startTime	long: millis	45022020250
succeded	boolean	true

codeSize	ulong: bytes	4048
compileId	uint	14611
compileLevel	ushort	4
compiler	CompilerType	c2
inlinedBytes	ulong: bytes	335
isOsr	boolean	false
method	Method
descriptor	string	([Ljava/lang/Object;)[Ljava/lang/Object;
hidden	boolean	false
modifiers	int	1
name	string	toArray
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
startTime	long: millis	52713186292
succeded	boolean	true

codeSize	ulong: bytes	20344
compileId	uint	6146
compileLevel	ushort	4
compiler	CompilerType	c2
inlinedBytes	ulong: bytes	3180
isOsr	boolean	false
method	Method
descriptor	string	(Lscala/PartialFunction;Ljava/lang/Object;)V
hidden	boolean	false
modifiers	int	1
name	string	aroundReceive
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	1057
name	string	edu/rice/habanero/actors/AkkaActor
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/actors
startTime	long: millis	33221039208
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	uint	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	uint	Compilation Identifier

Examples 3

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

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

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

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	uint	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	1
callee	CalleeMethod
descriptor	string	()Z
name	string	isLatin1
type	string	java/lang/String
caller	Method
descriptor	string	(I)C
hidden	boolean	false
modifiers	int	1
name	string	charAt
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	uint	1514
message	string	inline
startTime	long: millis	481058125
succeeded	boolean	true

bci	int	66
callee	CalleeMethod
descriptor	string	(B)V
name	string	putByte
type	string	jdk/jfr/internal/event/EventWriter
caller	Method
descriptor	string	(Ljava/lang/String;)V
hidden	boolean	false
modifiers	int	1
name	string	putString
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	49
name	string	jdk/jfr/internal/event/EventWriter
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/jdk.jfr
name	string	jdk.jfr
version	string	21.0.1
name	string	jdk/jfr/internal/event
compileId	uint	1493
message	string	callee uses too much stack
startTime	long: millis	340322375
succeeded	boolean	false

bci	int	6
callee	CalleeMethod
descriptor	string	()I
name	string	length
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	uint	1429
message	string	inline
startTime	long: millis	687906083
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	uint	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	reinterpret
bci	int	17
compileId	uint	1954
compiler	CompilerType	c2
instruction	Bytecode	ifge
lineNumber	int	53
method	Method
descriptor	string	([BII)I
hidden	boolean	false
modifiers	int	9
name	string	countPositives
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	java/lang/StringCoding
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	17
lineNumber	int	53
method	Method
descriptor	string	([BII)I
hidden	boolean	false
modifiers	int	9
name	string	countPositives
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	32
name	string	java/lang/StringCoding
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	4924368125

action	DeoptimizationAction	maybe_recompile
bci	int	242
compileId	uint	2114
compiler	CompilerType	c2
instruction	Bytecode	invokevirtual
lineNumber	int	1039
method	Method
descriptor	string	(Ljava/lang/Object;Ljava/lang/Object;Z)Ljava/lang/Object;
hidden	boolean	false
modifiers	int	16
name	string	putVal
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/concurrent/ConcurrentHashMap
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
reason	DeoptimizationReason	class_check
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	242
lineNumber	int	1039
method	Method
descriptor	string	(Ljava/lang/Object;Ljava/lang/Object;Z)Ljava/lang/Object;
hidden	boolean	false
modifiers	int	16
name	string	putVal
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/concurrent/ConcurrentHashMap
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	JIT compiled
		…
truncated	boolean	false
startTime	long: millis	1854821250

action	DeoptimizationAction	maybe_recompile
bci	int	202
compileId	uint	2956
compiler	CompilerType	c2
instruction	Bytecode	invokeinterface
lineNumber	int	1228
method	Method
descriptor	string	(Ljava/lang/Object;Ljava/util/function/Function;)Ljava/lang/Object;
hidden	boolean	false
modifiers	int	1
name	string	computeIfAbsent
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/HashMap
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
reason	DeoptimizationReason	class_check
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	202
lineNumber	int	1228
method	Method
descriptor	string	(Ljava/lang/Object;Ljava/util/function/Function;)Ljava/lang/Object;
hidden	boolean	false
modifiers	int	1
name	string	computeIfAbsent
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/HashMap
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	JIT compiled
		…
truncated	boolean	false
startTime	long: millis	3702782541

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	2
compileCount	int	4408
invalidatedCount	int	0
nmethodCodeSize	ulong: bytes	5079824
nmethodsSize	ulong: bytes	7702880
osrBytesCompiled	ulong: bytes	0
osrCompileCount	int	51
peakTimeSpent	long: millis	238
standardBytesCompiled	ulong: bytes	0
standardCompileCount	int	4357
startTime	long: millis	8447650084
totalTimeSpent	long: millis	4764

bailoutCount	int	4
compileCount	int	8247
invalidatedCount	int	0
nmethodCodeSize	ulong: bytes	10446232
nmethodsSize	ulong: bytes	15918392
osrBytesCompiled	ulong: bytes	0
osrCompileCount	int	97
peakTimeSpent	long: millis	4774
standardBytesCompiled	ulong: bytes	0
standardCompileCount	int	8150
startTime	long: millis	87882793500
totalTimeSpent	long: millis	56256

bailoutCount	int	6
compileCount	int	19532
invalidatedCount	int	0
nmethodCodeSize	ulong: bytes	23288848
nmethodsSize	ulong: bytes	36471160
osrBytesCompiled	ulong: bytes	0
osrCompileCount	int	170
peakTimeSpent	long: millis	1068
standardBytesCompiled	ulong: bytes	0
standardCompileCount	int	19362
startTime	long: millis	76964467458
totalTimeSpent	long: millis	48422

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

Examples 3

startTime	long: millis	43601129750
threadCount	int	4
tieredCompilation	boolean	true

startTime	long: millis	98901675542
threadCount	int	4
tieredCompilation	boolean	true

startTime	long: millis	82931736500
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

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 ns
profiling	true	true	0 ns

Field	Type	Description
destination	string	Destination
size	long	Size
gcBeforeDump	boolean	GC Before Dump
onOutOfMemoryError	boolean	On Out of Memory Error

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	JavaPriority3_To_OSPriority
origin	FlagValueOrigin	Default
startTime	long: millis	482135667
value	int	-1

name	string	JavaPriority7_To_OSPriority
origin	FlagValueOrigin	Default
startTime	long: millis	689925125
value	int	-1

name	string	JavaPriority1_To_OSPriority
origin	FlagValueOrigin	Default
startTime	long: millis	340853083
value	int	-1

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	TypeProfileLevel
origin	FlagValueOrigin	Default
startTime	long: millis	340856916
value	uint	111

name	string	ErrorHandlerTest
origin	FlagValueOrigin	Default
startTime	long: millis	689928291
value	uint	0

name	string	SharedSymbolTableBucketSize
origin	FlagValueOrigin	Default
startTime	long: millis	20956137292
value	uint	4

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	TieredCompileTaskTimeout
origin	FlagValueOrigin	Default
startTime	long: millis	482150084
value	long	50

name	string	BlockLayoutMinDiamondPercentage
origin	FlagValueOrigin	Default
startTime	long: millis	689937458
value	long	20

name	string	Tier4MinInvocationThreshold
origin	FlagValueOrigin	Default
startTime	long: millis	340867083
value	long	600

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	BreakAtNode
origin	FlagValueOrigin	Default
startTime	long: millis	689956458
value	ulong	0

name	string	GCOverheadLimitThreshold
origin	FlagValueOrigin	Default
startTime	long: millis	340882041
value	ulong	5

name	string	GCDrainStackTargetSize
origin	FlagValueOrigin	Default
startTime	long: millis	482164667
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	ZCollectionIntervalMajor
origin	FlagValueOrigin	Default
startTime	long: millis	75476137958
value	double	-1.0

name	string	ZCollectionIntervalMajor
origin	FlagValueOrigin	Default
startTime	long: millis	48589487625
value	double	-1.0

name	string	SelfDestructTimer
origin	FlagValueOrigin	Default
startTime	long: millis	59659464792
value	double	0.0

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	ImplicitDiv0Checks
origin	FlagValueOrigin	Default
startTime	long: millis	340898000
value	boolean	true

name	string	ImplicitDiv0Checks
origin	FlagValueOrigin	Default
startTime	long: millis	689971291
value	boolean	true

name	string	UseCryptoPmullForCRC32
origin	FlagValueOrigin	Default
startTime	long: millis	482184334
value	boolean	false

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	UseBranchProtection
origin	FlagValueOrigin	Default
startTime	long: millis	690006500
value	string	none

name	string	StartFlightRecording
origin	FlagValueOrigin	Command line
startTime	long: millis	28294128375
value	string	filename=[...]/code/experiments/jfreventcollector/jfr/sample_UseSerialGC.jfr,settings=[...]/code/experiments/jfreventcollector/.cache/jfc.jfc

name	string	PerfDataSaveFile
origin	FlagValueOrigin	Default
startTime	long: millis	20956802292
value	string	null

JVM: GC: Collector

GarbageCollection

default profiling startTime duration 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	27
longestPause	Tickspan	12531542
name	GCName	G1New
startTime	long: millis	2822287333
sumOfPauses	Tickspan	12531542

cause	GCCause	Allocation Failure
gcId	uint	56
longestPause	Tickspan	851542
name	GCName	DefNew
startTime	long: millis	5397859708
sumOfPauses	Tickspan	851542

cause	GCCause	Allocation Failure
gcId	uint	12
longestPause	Tickspan	5291667
name	GCName	ParallelScavenge
startTime	long: millis	2153157250
sumOfPauses	Tickspan	5291667

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	35114727667

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	76899112791

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

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	30163337216
gcId	uint	110
startTime	long: millis	98902693209

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	68
startTime	long: millis	7158266125
tenuringThreshold	uint	1

gcId	uint	5
startTime	long: millis	1222591792
tenuringThreshold	uint	7

gcId	uint	2
startTime	long: millis	910883083
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	415
startTime	long: millis	82548194291

gcId	uint	121
startTime	long: millis	108403007417

gcId	uint	219
startTime	long: millis	177666751000

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	83
startTime	long: millis	63930764458
type	G1YCType	Normal

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	2
gcTimeRatio	uint	12
isExplicitGCConcurrent	boolean	false
isExplicitGCDisabled	boolean	false
oldCollector	GCName	G1Old
parallelGCThreads	uint	8
pauseTarget	long: millis	-9223372036854775808
startTime	long: millis	99181011500
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	46798443667
usesDynamicGCThreads	boolean	true
youngCollector	GCName	ParallelScavenge

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	73934707708
usesDynamicGCThreads	boolean	true
youngCollector	GCName	DefNew

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	496199959

initialTenuringThreshold	ubyte	7
maxTenuringThreshold	ubyte	15
startTime	long: millis	73934710083

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	101429847875
tlabRefillWasteLimit	ulong: bytes	64
usesTLABs	boolean	true

minTLABSize	ulong: bytes	2048
startTime	long: millis	99429347500
tlabRefillWasteLimit	ulong: bytes	64
usesTLABs	boolean	true

minTLABSize	ulong: bytes	2048
startTime	long: millis	97864786875
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	59803299709
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	73934712291
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	1431633920
minSize	ulong: bytes	89456640
newRatio	uint	2
startTime	long: millis	86888879958

maxSize	ulong: bytes	2575302656
minSize	ulong: bytes	1363144
newRatio	uint	2
startTime	long: millis	135072799791

maxSize	ulong: bytes	1431306240
minSize	ulong: bytes	89128960
newRatio	uint	2
startTime	long: millis	108530491167

JVM: GC: Detailed

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	44
gcTime	long: millis	170
pauseTarget	long: millis	200
startTime	long: millis	33790977375
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	46
allocationRegionsUsedAfter	ulong: bytes	96038640
allocationRegionsUsedBefore	ulong: bytes	1048576
bytesCopied	ulong: bytes	94990064
cSetRegions	uint	121
cSetUsedAfter	ulong: bytes	0
cSetUsedBefore	ulong: bytes	253755392
gcId	uint	82
regionsFreed	uint	121
startTime	long: millis	63559739125

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	538
gcId	uint	1
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	0
name	string	[Ljava/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	491145834
totalSize	ulong: bytes	24560

count	long	403
gcId	uint	1
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	48
name	string	jdk/jfr/internal/Control
package	Package
exported	boolean	true
module	Module
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
location	string	jrt:/jdk.jfr
name	string	jdk.jfr
version	string	21.0.1
name	string	jdk/jfr/internal
startTime	long: millis	694706541
totalSize	ulong: bytes	16120

count	long	10925
gcId	uint	1
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	702041958
totalSize	ulong: bytes	349600

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	33786269791
statistics	G1EvacuationStatistics
allocated	ulong: bytes	10485760
directAllocated	ulong: bytes	0
failureUsed	ulong: bytes	0
failureWaste	ulong: bytes	0
gcId	uint	44
regionEndWaste	ulong: bytes	0
regionsRefilled	uint	5
undoWaste	ulong: bytes	0
used	ulong: bytes	10483984
wasted	ulong: bytes	1776

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	87243582041
statistics	G1EvacuationStatistics
allocated	ulong: bytes	0
directAllocated	ulong: bytes	0
failureUsed	ulong: bytes	0
failureWaste	ulong: bytes	0
gcId	uint	99
regionEndWaste	ulong: bytes	0
regionsRefilled	uint	0
undoWaste	ulong: bytes	0
used	ulong: bytes	0
wasted	ulong: bytes	0

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	87080400
gcId	uint	22
lastMarkingDuration	long: millis	117
recentAllocationRate	double: bytes-per-second	0.0
recentMutatorAllocationSize	ulong: bytes	0
recentMutatorDuration	long: millis	103
startTime	long: millis	2146149416
targetOccupancy	ulong: bytes	266338304
threshold	ulong: bytes	119852236
thresholdPercentage	float: percentage	0.45

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	159383552
currentOccupancy	ulong: bytes	92042232
gcId	uint	24
ihopTargetOccupancy	ulong: bytes	253021388
predictedAllocationRate	double: bytes-per-second	2.081783379965887E8
predictedMarkingDuration	long: millis	185
predictionActive	boolean	false
startTime	long: millis	2292115208
threshold	ulong: bytes	119852236
thresholdPercentage	float: percentage	0.47368422

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 Scavange, 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 scavange 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	0
name	string	[B
package	Package	null
objectSize	ulong: bytes	24
plabSize	ulong: bytes	32752
startTime	long: millis	1224270459
tenured	boolean	false
tenuringAge	uint	1

gcId	uint	3
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	48
name	string	java/lang/invoke/LambdaForm$Name
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/invoke
objectSize	ulong: bytes	32
plabSize	ulong: bytes	4128
startTime	long: millis	930563375
tenured	boolean	true
tenuringAge	uint	1

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 Scavange, 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 scavange 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

ParallelGC
G1GC

gcId	uint	14
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	7832
startTime	long: millis	2362757917
tenured	boolean	true
tenuringAge	uint	1

gcId	uint	100
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	50192
startTime	long: millis	87426595750
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

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	55
size	ulong: bytes	216
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	5
lineNumber	int	87
method	Method
descriptor	string	(I)Lio/jenetics/internal/collection/ObjectStore;
hidden	boolean	false
modifiers	int	9
name	string	ofLength
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	io/jenetics/internal/collection/ObjectStore
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	io/jenetics/internal/collection
type	FrameType	JIT compiled
		…
truncated	boolean	false
startTime	long: millis	5339426125

gcId	uint	7
size	ulong: bytes	80
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	32
lineNumber	int	1180
method	Method
descriptor	string	(Ljava/lang/CharSequence;)Ljava/util/regex/Matcher;
hidden	boolean	false
modifiers	int	1
name	string	matcher
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	Inlined
		…
truncated	boolean	false
startTime	long: millis	1360246750

gcId	uint	32
size	ulong: bytes	2048
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	5
lineNumber	int	87
method	Method
descriptor	string	(I)Lio/jenetics/internal/collection/ObjectStore;
hidden	boolean	false
modifiers	int	9
name	string	ofLength
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	io/jenetics/internal/collection/ObjectStore
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	io/jenetics/internal/collection
type	FrameType	Inlined
		…
truncated	boolean	false
startTime	long: millis	14002379791

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

SerialGC
G1GC

age	uint	6
gcId	uint	2
size	ulong: bytes	0
startTime	long: millis	826027375

age	uint	6
gcId	uint	14
size	ulong: bytes	0
startTime	long: millis	1540714958

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	Free
index	uint	5
start	ulong: address	30075256832
startTime	long: millis	782197708
to	G1HeapRegionType	Eden
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	960
gcId	uint	37
objectClass	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	0
name	string	[Ljava/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	4101111666
totalSize	ulong: bytes	3642000

count	long	245524
gcId	uint	22
objectClass	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	edu.rice.habanero.benchmarks.uct.UctAkkaActorBenchmark$NodeActor$$$Lambda+0x0000000800446a18/457158418
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
startTime	long: millis	13696186625
totalSize	ulong: bytes	9820960

count	long	97
gcId	uint	8
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	1216042791
totalSize	ulong: bytes	316240

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 1

G1GC

index	uint	66
start	ulong: address	30203183104
startTime	long: millis	42526420250
type	G1HeapRegionType	Old
used	ulong: bytes	2097112

ZAllocationStall

default profiling startTime duration eventThread 15 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: ZGC

Missing in: G1GC, ParallelGC, SerialGC, ShenandoahGC

Time spent waiting for memory to become available

Configuration	enabled	threshold
default	true	0 ms
profiling	true	0 ms

Field	Type	Description
type	ZPageTypeType	Type Consider contributing a description to jfreventcollector.
size	ulong: bytes	Size

Examples 1

size	ulong: bytes	2097152
startTime	long: millis	21489010250
type	ZPageTypeType	Small

ZPageAllocation

default profiling startTime duration eventThread stackTrace 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: ZGC

Missing in: G1GC, ParallelGC, SerialGC, ShenandoahGC

Allocation of a ZPage

Configuration	enabled	stackTrace	threshold
default	true	true 15+	1 ms
profiling	true	true 15+	1 ms

Field	Type	Description
type	ZPageTypeType 15+	Type Consider contributing a description to jfreventcollector.
size	ulong: bytes 15+	Size
flushed	ulong: bytes 15+	Flushed
committed	ulong: bytes 15+	Committed
segments	uint 15+	Segments
nonBlocking	boolean	Non-blocking

Examples 1

committed	ulong: bytes	2097152
flushed	ulong: bytes	0
nonBlocking	boolean	false
segments	uint	1
size	ulong: bytes	2097152
stackTrace	StackTrace
frames	StackFrame
bytecodeIndex	int	133
lineNumber	int	710
method	Method
descriptor	string	()[Ljava/util/HashMap$Node;
hidden	boolean	false
modifiers	int	16
name	string	resize
type	Class
classLoader	ClassLoader
name	string	bootstrap
type	Class	null
hidden	boolean	false
modifiers	int	33
name	string	java/util/HashMap
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	JIT compiled
		…
truncated	boolean	false
startTime	long: millis	2299092209
type	ZPageTypeType	Small

ZRelocationSet

default profiling startTime duration eventThread 15 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: ZGC

Missing in: G1GC, ParallelGC, SerialGC, ShenandoahGC

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

Configuration	enabled	threshold
default	true	0 ms
profiling	true	0 ms

Field	Type	Description
total	ulong: bytes	Total
empty	ulong: bytes	Empty
relocate	ulong: bytes 16+	Relocate

Examples 1

empty	ulong: bytes	1933574144
relocate	ulong: bytes	1664200
startTime	long: millis	3096630917
total	ulong: bytes	2092957696

ZRelocationSetGroup

default profiling startTime duration eventThread 15 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: ZGC

Missing in: G1GC, ParallelGC, SerialGC, ShenandoahGC

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

Configuration	enabled	threshold
default	true	0 ms
profiling	true	0 ms

Field	Type	Description
type	ZPageTypeType	Type Consider contributing a description to jfreventcollector.
pages	ulong 17 until JDK 21	Pages
total	ulong: bytes	Total
empty	ulong: bytes	Empty
relocate	ulong: bytes 16+	Relocate

Examples 1

empty	ulong: bytes	0
relocate	ulong: bytes	0
startTime	long: millis	1584233750
total	ulong: bytes	14680064
type	ZPageTypeType	Large

ZStatisticsCounter

experimental startTime duration eventThread 11 17 21 22

Category: Java Virtual Machine / GC / Detailed

Appearing in: ZGC

Missing in: G1GC, ParallelGC, SerialGC, ShenandoahGC