paramètres du journal de la machine virtuelle jvm
Site officiel: https://docs.oracle.com/en/java/javase/14/docs/specs/man/java.html#advanced-runtime-options-for-java
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-Format de commande Xlog
-Xlog[:[selections][:[output][:[decorators][:output-options]]]]
-Xlog: active la sortie du journal, la valeur par défaut est -Xlog: all = avertissement: stdout: uptime, level, tags
-Xlog: aide: Affichez l'utilisation du paramètre -Xlog
-Xlog: désactiver: désactiver la sortie du journal -Xlog
Paramètres de journal communs
-Xlog: gc: sortie du journal gc
-Xlog: gc *: sortie du journal gc détaillé
-Xlog: gc + heap = debug: affiche les informations du tas avant et après gc, ce qui équivaut à -XX: + PrintHeapAtGC, utilisé dans java9 et après
-Xlog: safepoint: simultanéité du thread utilisateur et temps de pause pendant la sortie de gc
-Xlog: gc + age = trace: après la sortie de gc, l'âge de la nouvelle génération
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sélections: tags + niveau, facultatif
Mots clés
Available log tags:
add, age, alloc, annotation, aot, arguments, attach, barrier, biasedlocking, blocks,
bot, breakpoint, bytecode, cds, census, class, classhisto, cleanup, codecache,
compaction, compilation, 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, init, inlining, install, interpreter, itables, jfr, jit, jni,
jvmti, liveness, load, loader, logging, malloc, mark, marking, membername, memops,
metadata, metaspace, methodcomparator, mirror, mmu, module, monitorinflation,
monitormismatch, nestmates, nmethod, normalize, numa, objecttagging, obsolete, oldobject,
oom, oopmap, oops, oopstorage, os, pagesize, parser, patch, path, perf, periodic, phases,
plab, preorder, preview, promotion, protectiondomain, ptrqueue, purge, record, redefine,
ref, refine, region, reloc, remset, resolve, safepoint, sampling, scavenge, setting, smr,
stackmap, stacktrace, stackwalk, start, startuptime, state, stats, streaming,
stringdedup, stringtable, subclass, survivor, sweep, symboltable, system, table, task,
thread, time, timer, tlab, tracking, unload, unshareable, update, verification, verify,
vmmutex, vmoperation, vmthread, vtables, vtablestubs, workgang
Specifying 'all' instead of a tag combination matches all tag combinations.
niveau: désactivé, trace, débogage, info, avertissement, erreur
Exemples:
all: contient toutes les balises
gc: journaux avec uniquement des balises gc
gc *: balise contenant gc
phases gc +: seuls les journaux de gc et de phrases, pas de gc et de phases séparés sont sortis
gc + phases *: journaux de sortie contenant gc et phases
gc = trace: journaux de sortie avec un niveau de journal de trace ou supérieur
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sortie: position de sortie
stdout: sortie vers la console
stderr: sortie d'erreur
fichier = nom_fichier: sortie dans un fichier
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décorations: format de sortie du journal, facultatif, la valeur par défaut est la disponibilité, le niveau, les balises
heure, t: heure actuelle, heure du fuseau horaire actuel, par exemple: [2020-04-02T16: 17: 54.614 + 0800]
utctime, utc: heure universelle, 0 fuseau horaire, comme: [2020-04-02T08: 17: 54.614 + 0000]
timemills, tm: la valeur de System.currentTimeMillis (), telle que: [1585815474614ms]
timenanos, tn: la valeur de System.nanoTime (), par exemple: [108171620762600ns]
uptime, u: intervalle de temps entre le début de la machine virtuelle et l'heure actuelle, tel que: [0.179s]
uptimemillis, um: le nombre de millisecondes écoulées depuis le démarrage de la machine virtuelle, tel que: [171ms]
uptimenanos, un: temps écoulé entre le démarrage de la machine virtuelle et le courant, en nanosecondes, tel que: [108303677015300ns]
nom d'hôte, hn: nom d'hôte
pid, p: identifiant du processus
tid, ti: id du thread
niveau, l: niveau du journal
balises, tg: nom de balise
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Des exemples
public class Test {
public static void main(String[] args){
byte[] b=new byte[1024*1024];
b=null;
System.gc();
}
}
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Sortie console
Paramètres de la machine virtuelle: -XX: + UseParallelGC -Xlog: gc *: stdout: time, utc, uptime, hostname, pid, tid, level, tags
[2020-04-02T16:30:54.480+0800][2020-04-02T08:30:54.480+0000][0.027s][LAPTOP-D73GD8TE][6480][1664][info][gc,heap,coops] Heap address: 0x0000000081c00000, size: 2020 MB, Compressed Oops mode: 32-bit
[2020-04-02T16:30:54.483+0800][2020-04-02T08:30:54.483+0000][0.028s][LAPTOP-D73GD8TE][6480][1664][info][gc ] Using Parallel
[2020-04-02T16:30:54.600+0800][2020-04-02T08:30:54.600+0000][0.146s][LAPTOP-D73GD8TE][6480][4388][info][gc,start ] GC(0) Pause Young (System.gc())
[2020-04-02T16:30:54.602+0800][2020-04-02T08:30:54.602+0000][0.148s][LAPTOP-D73GD8TE][6480][4388][info][gc,heap ] GC(0) PSYoungGen: 9472K(38400K)->968K(38400K) Eden: 9472K(33280K)->0K(33280K) From: 0K(5120K)->968K(5120K)
[2020-04-02T16:30:54.602+0800][2020-04-02T08:30:54.602+0000][0.148s][LAPTOP-D73GD8TE][6480][4388][info][gc,heap ] GC(0) ParOldGen: 0K(87552K)->8K(87552K)
[2020-04-02T16:30:54.602+0800][2020-04-02T08:30:54.602+0000][0.148s][LAPTOP-D73GD8TE][6480][4388][info][gc,metaspace ] GC(0) Metaspace: 624K(4864K)->624K(4864K) NonClass: 566K(4352K)->566K(4352K) Class: 58K(512K)->58K(512K)
[2020-04-02T16:30:54.602+0800][2020-04-02T08:30:54.602+0000][0.148s][LAPTOP-D73GD8TE][6480][4388][info][gc ] GC(0) Pause Young (System.gc()) 9M->0M(123M) 1.999ms
[2020-04-02T16:30:54.602+0800][2020-04-02T08:30:54.602+0000][0.148s][LAPTOP-D73GD8TE][6480][4388][info][gc,cpu ] GC(0) User=0.00s Sys=0.00s Real=0.00s
[2020-04-02T16:30:54.602+0800][2020-04-02T08:30:54.602+0000][0.148s][LAPTOP-D73GD8TE][6480][4388][info][gc,start ] GC(1) Pause Full (System.gc())
[2020-04-02T16:30:54.602+0800][2020-04-02T08:30:54.602+0000][0.148s][LAPTOP-D73GD8TE][6480][4388][info][gc,phases,start] GC(1) Marking Phase
[2020-04-02T16:30:54.604+0800][2020-04-02T08:30:54.604+0000][0.149s][LAPTOP-D73GD8TE][6480][4388][info][gc,phases ] GC(1) Marking Phase 1.591ms
[2020-04-02T16:30:54.604+0800][2020-04-02T08:30:54.604+0000][0.150s][LAPTOP-D73GD8TE][6480][4388][info][gc,phases,start] GC(1) Summary Phase
[2020-04-02T16:30:54.604+0800][2020-04-02T08:30:54.604+0000][0.150s][LAPTOP-D73GD8TE][6480][4388][info][gc,phases ] GC(1) Summary Phase 0.015ms
[2020-04-02T16:30:54.604+0800][2020-04-02T08:30:54.604+0000][0.150s][LAPTOP-D73GD8TE][6480][4388][info][gc,phases,start] GC(1) Adjust Roots
[2020-04-02T16:30:54.605+0800][2020-04-02T08:30:54.605+0000][0.150s][LAPTOP-D73GD8TE][6480][4388][info][gc,phases ] GC(1) Adjust Roots 0.652ms
[2020-04-02T16:30:54.605+0800][2020-04-02T08:30:54.605+0000][0.150s][LAPTOP-D73GD8TE][6480][4388][info][gc,phases,start] GC(1) Compaction Phase
[2020-04-02T16:30:54.607+0800][2020-04-02T08:30:54.607+0000][0.153s][LAPTOP-D73GD8TE][6480][4388][info][gc,phases ] GC(1) Compaction Phase 2.365ms
[2020-04-02T16:30:54.607+0800][2020-04-02T08:30:54.607+0000][0.153s][LAPTOP-D73GD8TE][6480][4388][info][gc,phases,start] GC(1) Post Compact
[2020-04-02T16:30:54.607+0800][2020-04-02T08:30:54.607+0000][0.153s][LAPTOP-D73GD8TE][6480][4388][info][gc,phases ] GC(1) Post Compact 0.048ms
[2020-04-02T16:30:54.607+0800][2020-04-02T08:30:54.607+0000][0.153s][LAPTOP-D73GD8TE][6480][4388][info][gc,heap ] GC(1) PSYoungGen: 968K(38400K)->0K(38400K) Eden: 0K(33280K)->0K(33280K) From: 968K(5120K)->0K(5120K)
[2020-04-02T16:30:54.607+0800][2020-04-02T08:30:54.607+0000][0.153s][LAPTOP-D73GD8TE][6480][4388][info][gc,heap ] GC(1) ParOldGen: 8K(87552K)->925K(87552K)
[2020-04-02T16:30:54.607+0800][2020-04-02T08:30:54.607+0000][0.153s][LAPTOP-D73GD8TE][6480][4388][info][gc,metaspace ] GC(1) Metaspace: 624K(4864K)->624K(4864K) NonClass: 566K(4352K)->566K(4352K) Class: 58K(512K)->58K(512K)
[2020-04-02T16:30:54.607+0800][2020-04-02T08:30:54.607+0000][0.153s][LAPTOP-D73GD8TE][6480][4388][info][gc ] GC(1) Pause Full (System.gc()) 0M->0M(123M) 4.869ms
[2020-04-02T16:30:54.607+0800][2020-04-02T08:30:54.607+0000][0.153s][LAPTOP-D73GD8TE][6480][4388][info][gc,cpu ] GC(1) User=0.00s Sys=0.00s Real=0.01s
[2020-04-02T16:30:54.608+0800][2020-04-02T08:30:54.608+0000][0.153s][LAPTOP-D73GD8TE][6480][1664][info][gc,heap,exit ] Heap
[2020-04-02T16:30:54.608+0800][2020-04-02T08:30:54.608+0000][0.154s][LAPTOP-D73GD8TE][6480][1664][info][gc,heap,exit ] PSYoungGen total 38400K, used 1664K [0x00000000d5f00000, 0x00000000d8980000, 0x0000000100000000)
[2020-04-02T16:30:54.608+0800][2020-04-02T08:30:54.608+0000][0.154s][LAPTOP-D73GD8TE][6480][1664][info][gc,heap,exit ] eden space 33280K, 5% used [0x00000000d5f00000,0x00000000d60a01e8,0x00000000d7f80000)
[2020-04-02T16:30:54.608+0800][2020-04-02T08:30:54.608+0000][0.154s][LAPTOP-D73GD8TE][6480][1664][info][gc,heap,exit ] from space 5120K, 0% used [0x00000000d7f80000,0x00000000d7f80000,0x00000000d8480000)
[2020-04-02T16:30:54.608+0800][2020-04-02T08:30:54.608+0000][0.154s][LAPTOP-D73GD8TE][6480][1664][info][gc,heap,exit ] to space 5120K, 0% used [0x00000000d8480000,0x00000000d8480000,0x00000000d8980000)
[2020-04-02T16:30:54.608+0800][2020-04-02T08:30:54.608+0000][0.154s][LAPTOP-D73GD8TE][6480][1664][info][gc,heap,exit ] ParOldGen total 87552K, used 925K [0x0000000081c00000, 0x0000000087180000, 0x00000000d5f00000)
[2020-04-02T16:30:54.608+0800][2020-04-02T08:30:54.608+0000][0.154s][LAPTOP-D73GD8TE][6480][1664][info][gc,heap,exit ] object space 87552K, 1% used [0x0000000081c00000,0x0000000081ce76d0,0x0000000087180000)
[2020-04-02T16:30:54.608+0800][2020-04-02T08:30:54.608+0000][0.154s][LAPTOP-D73GD8TE][6480][1664][info][gc,heap,exit ] Metaspace used 627K, capacity 4531K, committed 4864K, reserved 1056768K
[2020-04-02T16:30:54.608+0800][2020-04-02T08:30:54.608+0000][0.154s][LAPTOP-D73GD8TE][6480][1664][info][gc,heap,exit ] class space used 58K, capacity 402K, committed 512K, reserved 1048576K
