Reading · Random Notes and Cheat Sheets

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As mentioned in my previous posting on Unified Logging (UL), messages will be associated with both a level and a tag set. The levels are trace, debug, info, warning , and error . Tags can be listed by running java -Xlog:help . The output from JDK 17 is listed here. add, age, alloc, annotation, arguments, attach, barrier, biasedlocking, blocks, bot, breakpoint, bytecode, cds, census, class,…

As mentioned in my previous posting on Unified Logging (UL), messages will be associated with both a level and a tag set. The levels are trace, debug, info, warning, and error. Tags can be listed by running java -Xlog:help. The output from JDK 17 is listed here.

add, age, alloc, annotation, arguments, attach, barrier, biasedlocking, blocks, bot, breakpoint, bytecode, cds, census, class, classhisto, cleanup, codecache, compaction, compilation, condy, constantpool, constraints, container, coops, cpu, cset, data, datacreation, dcmd, decoder, defaultmethods, director, dump, dynamic, ergo, event, exceptions, exit, fingerprint, free, freelist, gc, handshake, hashtables, heap, humongous, ihop, iklass, indy, init, inlining, install, interpreter, itables, jfr, jit, jni, jvmci, jvmti, lambda, library, liveness, load, loader, logging, malloc, map, mark, marking, membername, memops, metadata, metaspace, methodcomparator, methodhandles, mirror, mmu, module, monitorinflation, monitormismatch, nestmates, nmethod, nmt, normalize, numa, objecttagging, obsolete, oldobject, oom, oopmap, oops, oopstorage, os, owner, pagesize, parser, patch, path, perf, periodic, phases, plab, placeholders, preorder, preview, promotion, protectiondomain, ptrqueue, purge, record, redefine, ref, refine, region, reloc, remset, resolve, safepoint, sampling, scavenge, sealed, setting, smr, stackbarrier, stackmap, stacktrace, stackwalk, start, startup, startuptime, state, stats, streaming, stringdedup, stringtable, subclass, survivor, suspend, sweep, symboltable, system, table, task, thread, throttle, time, timer, tlab, tracking, unload, unshareable, update, valuebasedclasses, verification, verify, vmmutex, vmoperation, vmthread, vtables, vtablestubs, workgang

Tags Sets

The following table lists tag sets at each logging level available in the product build.

Trace	Debug	Info	Warning	Error
arguments	attach	arguments	arguments	arguments
attach	cds	cds	cds	attach
cds	cds, class	cds, dynamic	cds, dynamic	cds
cds, heap, mirror	cds, dynamic	cds, hashtables	cds, heap	cds, heap
cds, mirror	cds, heap	cds, heap	codecache	class
cds, unshareable	cds, jvmti	cds, lambda	exceptions	gc
cds, verification	cds, lambda	cds, map	gc	gc, marking
cds, hashtables	cds, map	cds, module	gc, alloc	gc, task
class, init	cds, mirror	cds, dynamic	gc, cpu	gc, verify
class, nestmates	cds, reloc	class, init	gc, ergo	handshake
class, sealed	cds, resolve	class, load	gc, init	jfr
class, unload	cds, vtables	class, loader, data	gc, jvmci	jfr, system
continuations	class, loader, data	class, nestmates	gc, verify	jfr, system
ergo	class, nestmates	class, path	if	jfr, startup
evt,out	class, path	class, preview	jfr	jvmti
gc	class, resolve	class, unload	jfr, startup	logging
gc, age	codecache	codecache	jfr, system	monitorinflation
gc, alloc	defaultmethods	compilation	jfr, startup	os
gc, barrier	exceptions	exceptions	jni, resolve
gc, bot	gc	finalizer	jvmti
gc, breakpoint	gc, age	gc	logging
gc, ergo	gc, alloc	gc, classhisto	logging, thread
gc, ergo, cset	gc, alloc, region	gc, cpu	malloc, free
gc, ergo, heap	gc, alloc, stats	gc, ergo	metaspace
gc, freelist	gc, breakpoint	gc, heap	nmt
gc, heap	gc, director	gc, init	os
gc, heap, coops	gc, ergo	gc, load	os, thread
gc, heap, numa	gc, ergo, cset	gc, marking	pagesize
gc, liveness	gc, ergo, heap	gc, metaspace	perf, memops
gc, marking	gc, ergo, ihop	gc, mmu	safepoint
gc, metaspace	gc, ergo, refine	gc, nmethod	stringdedup
gc, metaspace, freelist	gc, heap	gc, phases	stringtable
gc, nmethod	gc, heap, coops	gc, phases	symboltable
gc, phases	gc, heap, exit	gc, promotion
gc, plab	gc, heap, region	gc, ref
gc, ref	gc, humongous	gc, region, cds
gc, refine	gc, ihop	gc, reloc
gc, region	gc, init	gc, start
gc, reloc	gc, jni	gc, task
gc, remset, tracking	gc, marking	gc, heap
gc, task	gc, mmu	gc, ref
gc, tlab	gc, nmethod	gc, start
gc, ref	gc, periodic	gc, task
handshake	gc, phases	handshake
interpreter, oopmap	gc, plab	jfr
jfr	gc, promotion	jfr, startup
jfr, oldobject, sampling	gc, ref	jvmti, table
jfr, system	gc, refine	library
jvmti	gc, refine, stats	logging
logging	gc, remset	membername, table
membername, table	gc, remset, tracking	metaspace
membername, table	gc, stats	methodhandles
metaspace	gc, task	module, load
module	gc, task, start	module, unload
module, patch	gc, tlab	monitorinflation
monitorinflation	gc, verify	monitormismatch
monitorinflation, owner	gc, ergo	oopstorage, blocks
nmethod, barrier	handshake, task	oopstorage, blocks, stats
oopstorage, blocks	interpreter, oopmap	os
oopstorage, ref	interpreter, safepoint	os, cpu
os	jfr, startup	os, thread
os, container	jfr, system	pagesize
os, thread	jfr, system, throttle	perf, memops
pagesize	jit, inlining	redefine, class
protectiondomain	jni	redefine, class, constantpool
redefine, class	jni, resolve	redefine, class, load
redefine, class, constantpool	logging	redefine, class, load, exceptions
redefine, class, dump	logging, thread	redefine, class, nestmates
redefine, class, iklass, add	membername, table	redefine, class, normalize
redefine, class, iklass, add	metaspace	redefine, class, record
redefine, class, iklass, purge	methodhandles, indy	redefine, class, timer
redefine, class, normalize	module	redefine, class, update
redefine, class, obsolete	nmt	safepoint
redefine, class, obsolete, mark	oopstorage, blocks	safepoint, stats
redefine, class, obsolete, metadata	os	stackbarrier
redefine, class, update, constantpool	os, container	stacktrace
redefine, class, update, itables	os, thread	stringdedup
redefine, class, update, vtables	os, thread, timer	stringdedup, init
safepoint	pagesize	stringtable
stringdedup	perf, datacreation	symboltable
stringtable	perf, memops	thread, table
symboltable	redefine, class, annotation	valuebasedclasses
thread, suspend	redefine, class, breakpoint	verification
thread, table	redefine, class, constantpool
thread, table	redefine, class, interpreter, oopmap
vmmutex	redefine, class, load
vmthread	redefine, class, methodcomparator
vtablestubs	redefine, class, nmethod
	redefine, class, stackmap
	redefine, class, subclass
	redefine, class, update, constantpool
	redefine, class, update, vtables
	safepoint
	stackbarrier
	stackwalk
	stringdedup
	stringdedup, phases
	stringdedup, phases, start
	stringtable
	stringtable, perf
	symboltable
	symboltable, perf
	thread
	thread, smr
	thread, table
	verification
	vmthread

If there are any missing, please shout out in the comments below.

Unified Logging Tag Sets in OpenJDK

Tags Sets

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