C Events

The Flight Recorder records "events" that occur during run time. An event is a distinct data point with associated data; that is, it is any occurrence during run time that can be recorded, such as the CPU load at a certain time or a thread waiting for a lock. These events are then reported on the Flight Recorder GUI to provide insight into system health and behavior.

This appendix describes the structure of events and how these events are used. This list describes the events reported by the JVM and class libraries only. Additional events are available from applications running on the JVM (such as WebLogic Server).

Note:

This appendix contains a number of Oracle JRockit- and JVM-specific terms that might be unfamiliar to you. If you encounter any unfamiliar terminology, we recommend you refer to the other documentation in the Oracle JRockit library.

Table C-1 lists the events you can capture in a flight recording.

Table C-1 JRockit Flight Recorder Events

Name Description Path

Exception Thrown

  

java/exception_throw

File Read

Reading from Java FileInputStream/RandomAccessFile/FileChannel

java/file_read

File Write

Writing to Java FileInputStream/RandomAccessFile/FileChannel

java/file_write

Java Monitor Enter

Entering Java monitor

java/monitor_enter

Java Monitor Wait

Waiting for Java monitor

java/monitor_wait

Object Allocated in New TLA

Object was allocated, which required a new thread local area (TLA) to be retrieved

java/object_alloc_in_new_tla

Object Allocated outside TLA

Object was allocated outside a TLA, directly on the heap

java/object_alloc_outside_tla

Socket Read

Reading from Java Socket/SocketChannel

java/socket_read

Socket Write

Writing to Java Socket/SocketChannel

java/socket_write

Allocated by Thread

Total number of bytes and TLAs that have been allocated by the thread

java/statistics/alloc_thread

Allocated by All Threads

Summary of the total number of bytes and TLAs that have been allocated, for all threads

java/statistics/alloc_total

Exception Count

Accumulated number of thrown exceptions

java/statistics/exceptions

Java Lock Profiling Snapshot

Detailed profiling information on Java locking for class

java/statistics/lock_profile

Java Thread Statistics

  

java/statistics/threads

Java Thread End

  

java/thread_end

Java Thread Park

Waiting in LockSupport.park()

java/thread_park

Java Thread Sleep

  

java/thread_sleep

Java Thread Start

  

java/thread_start

Thread Context Switch Rate

  

os/context_switch_rate

CPU Load Sample

    

Environment Variables

  

os/environment

Physical Memory Statistics

  

os/physical_memory

Active System Processes

  

os/processes

List of Active Recordings

  

recordings/active

Event Settings Changed

  

recordings/settingsChanged

Class GC Free Data

  

vm/class/free

Class Load

  

vm/class/load

Class GC Unlink

Removal of unreachable classes

vm/class/unlink

Class Unload

  

vm/class/unload

Code GC Call Prune

Removal of calls to obsolete code

vm/codegc/prune_calls

Code GC Code Prune

Cleanup of global lookup tables

vm/codegc/prune_code

Code GC Free Data

  

vm/codegc/release_code

Compiler Statistics

  

vm/compiler/compiler_statistics

Compilation Abort

Aborted compilation due to exception or error

vm/compiler/fail

JIT Code Compilation

  

vm/compiler/jit_compile

Method Inline

  

vm/compiler/method_inline

Optimized Code Compilation

  

vm/compiler/opt_compile

Code Performance Warning

Performance warning for compiled method

vm/compiler/performance_log

JIT Compiler Phase Level 1

Statistics for specific JIT compilation phase

vm/compiler/phases/jit_phase_level_1

JIT Compiler Phase Level 2

Statistics for specific JIT compilation phase

vm/compiler/phases/jit_phase_level_2

JIT Compiler Phase Level 3

Statistics for specific JIT compilation phase

vm/compiler/phases/jit_phase_level_3

JIT Compiler Phase Trace Level 1

Detailed statistics for specific JIT compilation phase

vm/compiler/phases/jit_phase_trace_level_1

JIT Compiler Phase Trace Level 2

Detailed statistics for specific JIT compilation phase

vm/compiler/phases/jit_phase_trace_level_2

JIT Compiler Phase Trace Level 3

Detailed statistics for specific JIT compilation phase

vm/compiler/phases/jit_phase_trace_level_3

Optimizer Phase Level 1

Statistics for specific code optimization phase

vm/compiler/phases/opt_phase_level_1

Optimizer Phase Level 2

Statistics for specific code optimization phase

vm/compiler/phases/opt_phase_level_2

Optimizer Phase Level 3

Statistics for specific code optimization phase

vm/compiler/phases/opt_phase_level_3

Optimizer Phase Trace Level 1

Detailed statistics for specific code optimization phase

vm/compiler/phases/opt_phase_trace_level_1

Optimizer Phase Trace Level 2

Detailed statistics for specific code optimization phase

vm/compiler/phases/opt_phase_trace_level_2

Optimizer Phase Trace Level 3

Detailed statistics for specific code optimization phase

vm/compiler/phases/opt_phase_trace_level_3

CPU Information

Detailed description of the CPU(s) in the system

vm/cpu_info

Free Memory Cache Bucket Element

Individual free memory cache bucket element

vm/freemem/cache_bucket_elem

Free Memory Cache Bucket Summary

Summary of an individual bucket in the free memory cache

vm/freemem/cache_bucket_total

Free Memory Cache Summary

Summary of free memory in the free memory cache, excluding the free memory list and the free memory TLA cache

vm/freemem/cache_total

Free Memory List Element

Individual free memory list element

vm/freemem/list_elem

Free Memory List Summary

Summary of free memory in the free memory list, excluding the free memory cache and the free memory TLA cache

vm/freemem/list_total

Pending Allocation Request Created

Pending allocation request is created by the thread

vm/gc/alloc_pending/request_created

Pending Allocation Request Got OOM

Pending allocation request was denied and turned into an OutOfMemoryException by the garbage collector

vm/gc/alloc_pending/request_got_oom

Pending Allocation Request Satisfied

Pending allocation request is satisfied by the garbage collector

vm/gc/alloc_pending/request_satisfied

Pending Allocations at GC End

Summary of the pending allocation requests at the end of the garbage collection

vm/gc/alloc_pending/summary_gc_end

Pending Allocations at GC Start

Summary of the pending allocation requests at the start of the garbage collection

vm/gc/alloc_pending/summary_gc_start

Compaction

Compaction of the live data on the heap, done as part of an old collection

vm/gc/compaction/compaction

Compaction Heap Shrink Preparation

Compaction prepared for shrinking the heap

vm/gc/compaction/heap_shrink_preparation

Compaction Move Phase

Move phase of a dual-phased compaction

vm/gc/compaction/phases/move

Compaction Update Phase

Update phase of a dual-phased compaction

vm/gc/compaction/phases/update

GC Configuration

Configuration of parameters for the garbage collector

vm/gc/configuration

Emergency Parallel Sweep Requested

Garbage collector changed sweep from concurrent to parallel due to special circumstances

vm/gc/emergency_parallel_sweep_requested

Garbage Collection

Garbage collection performed by the JVM (old collection or young collection)

vm/gc/garbage_collection

Heap Size Changed

Change of the heap size (expansion or contraction)

vm/gc/heap_size_changed

Heap Blocks Snapshot

Statistics for contiguous blocks of heap memory (used, free, dark matter)

vm/gc/heap_statistics/blocks

Heap Usage Snapshot

Statistics for classes that take up more than 0.5% of the heap

vm/gc/heap_statistics/class

GC History

Summary of previously finished garbage collections

vm/gc/history

GC Mode Changed

Garbage collector changed mode

vm/gc/mode_changed

Old Collection

Old collection performed by the JVM (collecting the whole heap)

vm/gc/oc/old_collection

OC Mark Phase

Mark phase of an old collection

vm/gc/oc/phases/mark

OC Sweep Phase

Sweep phase of an old collection

vm/gc/oc/phases/sweep

GC Concurrent Phase

Top-level phase of the garbage collection, during which the threads are running

vm/gc/phases/concurrent

GC Stopped Phase

Top-level phase of the garbage collection, during which the threads are stopped

vm/gc/phases/stopped

GC Transition Phase from Stopped

Top-level phase of the garbage collection, during which the threads are transitioning from stopped to running

vm/gc/phases/transition_from_stopped

GC Transition Phase to Stopped

Top-level phase of the garbage collection, during which the threads are transitioning from running to stopped

vm/gc/phases/transition_to_stopped

GC Concurrent Sub-Level 1 Phase

Sub-level phase of the garbage collection, during which the threads are running

vm/gc/phases_sublevels/level_1/concurrent

GC Stopped Sub-Level 1 Phase

Sub-level phase of the garbage collection, during which the threads are stopped

vm/gc/phases_sublevels/level_1/stopped

GC Concurrent Sub-Level 2 Phase

Sub-level phase of the garbage collection, during which the threads are running

vm/gc/phases_sublevels/level_2/concurrent

GC Stopped Sub-Level 2 Phase

Sub-level phase of the garbage collection, during which the threads are stopped

vm/gc/phases_sublevels/level_2/stopped

GC Concurrent Sub-Level 3 Phase

Sub-level phase of the garbage collection, during which the threads are running

vm/gc/phases_sublevels/level_3/concurrent

GC Stopped Sub-Level 3 Phase

Sub-level phase of the garbage collection, during which the threads are stopped

vm/gc/phases_sublevels/level_3/stopped

GC Concurrent Sub-Level 4 Phase

Sub-level phase of the garbage collection, during which the threads are running

vm/gc/phases_sublevels/level_4/concurrent

GC Stopped Sub-Level 4 Phase

Sub-level phase of the garbage collection, during which the threads are stopped

vm/gc/phases_sublevels/level_4/stopped

GC Requested

Garbage collection request generated by the requesting thread, including the reason for the garbage collection

vm/gc/request

Semiref Processing Phase Snapshot

Number of semirefs (reference objects and handles) that were processed during different garbage collection phases

vm/gc/semiref/counts_phase

Semiref State Snapshot

Number of semirefs (reference objects and handles) in different states

vm/gc/semiref/counts_state

Semiref Soft Alive Snapshot

Number of soft references that were soft alive (i.e. not eligible for garbage collection due to too recent access)

vm/gc/semiref/counts_state_softalive

Semiref Class Snapshot

Detailed information on all pairs of semiref and referent classes

vm/gc/semiref/details_class

Total Semiref Count

Total number of semirefs (reference objects and handles)

vm/gc/semiref/total

GC Strategy Changed

Garbage collector changed strategy

vm/gc/strategy_changed

Young Collector Nursery Snapshot

Updated status of the nursery after a young collection

vm/gc/yc/nursery

YC Promotion Failed

Promotion of an object failed during a young collection, since the old space of the heap is full

vm/gc/yc/promotion_failed

Young Collection

Young collection performed by the JVM (collecting the nursery only)

vm/gc/yc/young_collection

JVM Information

Description of JVM, Java application and Operating System

vm/info

Method Profiling Sample

Snapshot of the state of a thread

vm/prof/execution_sample

Method Hotspot Sample

A more lightweight sample of the state of a thread state. This redundant and not generated if 'execution_sample' is enabled.

vm/prof/hotspotsample

Memory Usage

Snapshot of JVM virtual memory footprint

vm/prof/memory_usage

JVM Event Wait

  

vm/sync/event_wait

JVM Lock Profiling Sample

Detailed profiling information on a JVM lock object

vm/sync/lock_profile

JVM Monitor Wait

  

vm/sync/monitor_wait

JVM Mutex Enter

  

vm/sync/mutex_enter

System Properties

System properties set at command line

vm/system_properties

JVM Thread Sleep

  

vm/thread/sleep

JVM Thread Suspend

Suspension of JVM Thread

vm/thread/suspend

JVM Thread Suspended

  

vm/thread/suspended