Arthas(阿尔萨斯)--(二)-编程知识

一、Arthas学习

1、JVM相关命令一

1、dashboard

2、thread

3、jvm

4、sysprop

一、Arthas学习

Arthas(阿尔萨斯)--(一)

Arthas代码开源地址

1、JVM相关命令一

1、dashboard

dashboard:显示当前系统的实时数据面板，按q或ctrl+c退出

ID: Java 级别的线程 ID，注意这个 ID 不能跟 jstack 中的 nativeID 一一对应。
NAME: 线程名
GROUP: 线程组名
PRIORITY: 线程优先级, 1~10 之间的数字，越大表示优先级越高
STATE: 线程的状态
CPU%: 线程的 cpu 使用率。比如采样间隔 1000ms，某个线程的增量 cpu 时间为 100ms，则 cpu 使用率=100/1000=10%
DELTA_TIME: 上次采样之后线程运行增量 CPU 时间，数据格式为秒
TIME: 线程运行总 CPU 时间，数据格式为分:秒
INTERRUPTED: 线程当前的中断位状态
DAEMON: 是否是 daemon 线程

2、thread

thread:查看当前JVM的线程堆栈信息

参数:数字:线程id
[n:]：指定最忙的前N个线程并打印堆栈

[arthas@14156]$ thread -n 3
"main" Id=1 cpuUsage=0.0% deltaTime=0ms time=218ms TIMED_WAITINGat java.base@21.0.1/java.lang.Thread.sleep0(Native Method)at java.base@21.0.1/java.lang.Thread.sleep(Thread.java:558)at java.base@21.0.1/java.util.concurrent.TimeUnit.sleep(TimeUnit.java:446)at app//demo.MathGame.main(MathGame.java:17)"Reference Handler" Id=9 cpuUsage=0.0% deltaTime=0ms time=0ms RUNNABLEat java.base@21.0.1/java.lang.ref.Reference.waitForReferencePendingList(Native Method)at java.base@21.0.1/java.lang.ref.Reference.processPendingReferences(Reference.java:246)at java.base@21.0.1/java.lang.ref.Reference$ReferenceHandler.run(Reference.java:208)"Finalizer" Id=10 cpuUsage=0.0% deltaTime=0ms time=0ms WAITING on java.lang.ref.NativeReferenceQueue$Lock@2b55402bat java.base@21.0.1/java.lang.Object.wait0(Native Method)-  waiting on java.lang.ref.NativeReferenceQueue$Lock@2b55402bat java.base@21.0.1/java.lang.Object.wait(Object.java:366)at java.base@21.0.1/java.lang.Object.wait(Object.java:339)at java.base@21.0.1/java.lang.ref.NativeReferenceQueue.await(NativeReferenceQueue.java:48)at java.base@21.0.1/java.lang.ref.ReferenceQueue.remove0(ReferenceQueue.java:158)at java.base@21.0.1/java.lang.ref.NativeReferenceQueue.remove(NativeReferenceQueue.java:89)at java.base@21.0.1/java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:173)[arthas@14156]$

[b]：找出当前阻塞其他线程的线程

有时候我们发现应用卡住了，通常是由于某个线程拿住了某个锁，并且其他线程都在等待这把锁造成的。为了排查这类问题， arthas 提供了thread -b

运行一个死锁程序

public class DeadLock {static Object a = new Object();static Object b = new Object();public static void main(String[] args) {new Thread(() -> {synchronized (a) {System.out.println(Thread.currentThread().getName() + "持有锁a,试图获取锁b");synchronized (b) {System.out.println(Thread.currentThread().getName() + "持有锁b");}}}, "t1").start();new Thread(() -> {synchronized (b) {System.out.println(Thread.currentThread().getName() + "持有锁b,试图获取锁a");synchronized (a) {System.out.println(Thread.currentThread().getName() + "持有锁a");}}}, "t2").start();}}

运行arthas，粘附到这个死锁程序中

[arthas@11400]$ thread -b
"t2" Id=34 BLOCKED on java.lang.Object@1e8eb080 owned by "t1" Id=33at app//com.lwz.xxx.DeadLock.lambda$main$1(DeadLock.java:21)-  blocked on java.lang.Object@1e8eb080-  locked java.lang.Object@6fe0e9fb <---- but blocks 1 other threads!at app//com.lwz.controller.DeadLock$$Lambda/0x0000020111003418.run(Unknown Source)at java.base@21.0.1/java.lang.Thread.runWith(Thread.java:1596)at java.base@21.0.1/java.lang.Thread.run(Thread.java:1583)[arthas@11400]$

[i <value>]：指定cpu占比统计的采样间隔，单位为毫秒

thread -i 1000 : 统计最近 1000ms 内的线程 CPU 时间。thread -n 3 -i 1000 : 列出 1000ms 内最忙的 3 个线程栈

[arthas@14156]$ thread -i 1000
Threads Total: 16, NEW: 0, RUNNABLE: 9, BLOCKED: 0, WAITING: 3, TIMED_WAITING: 4, TERMINATED: 0
ID   NAME                          GROUP          PRIORITY  STATE    %CPU      DELTA_TIM TIME      INTERRUPT DAEMON
1    main                          main           5         TIMED_WA 0.0       0.000     0:0.234   false     false
9    Reference Handler             system         10        RUNNABLE 0.0       0.000     0:0.000   false     true
10   Finalizer                     system         8         WAITING  0.0       0.000     0:0.000   false     true
11   Signal Dispatcher             system         9         RUNNABLE 0.0       0.000     0:0.000   false     true
12   Attach Listener               system         5         RUNNABLE 0.0       0.000     0:0.046   false     true
30   Notification Thread           system         9         RUNNABLE 0.0       0.000     0:0.000   false     true
31   Common-Cleaner                InnocuousThrea 8         TIMED_WA 0.0       0.000     0:0.000   false     true
33   arthas-timer                  system         5         WAITING  0.0       0.000     0:0.000   false     true
59   arthas-NettyHttpTelnetBootstr system         5         RUNNABLE 0.0       0.000     0:0.046   false     true
60   arthas-NettyWebsocketTtyBoots system         5         RUNNABLE 0.0       0.000     0:0.000   false     true
61   arthas-NettyWebsocketTtyBoots system         5         RUNNABLE 0.0       0.000     0:0.000   false     true
62   arthas-shell-server           system         5         TIMED_WA 0.0       0.000     0:0.000   false     true
63   arthas-session-manager        system         5         TIMED_WA 0.0       0.000     0:0.000   false     true
64   arthas-UserStat               system         5         WAITING  0.0       0.000     0:0.000   false     true
66   arthas-NettyHttpTelnetBootstr system         5         RUNNABLE 0.0       0.000     0:0.140   false     true
67   arthas-command-execute        system         5         RUNNABLE 0.0       0.000     0:0.046   false     true[arthas@14156]$ thread -n 3 -i 1000
"main" Id=1 cpuUsage=0.0% deltaTime=0ms time=234ms TIMED_WAITINGat java.base@21.0.1/java.lang.Thread.sleep0(Native Method)at java.base@21.0.1/java.lang.Thread.sleep(Thread.java:558)at java.base@21.0.1/java.util.concurrent.TimeUnit.sleep(TimeUnit.java:446)at app//demo.MathGame.main(MathGame.java:17)"Reference Handler" Id=9 cpuUsage=0.0% deltaTime=0ms time=0ms RUNNABLEat java.base@21.0.1/java.lang.ref.Reference.waitForReferencePendingList(Native Method)at java.base@21.0.1/java.lang.ref.Reference.processPendingReferences(Reference.java:246)at java.base@21.0.1/java.lang.ref.Reference$ReferenceHandler.run(Reference.java:208)"Finalizer" Id=10 cpuUsage=0.0% deltaTime=0ms time=0ms WAITING on java.lang.ref.NativeReferenceQueue$Lock@2b55402bat java.base@21.0.1/java.lang.Object.wait0(Native Method)-  waiting on java.lang.ref.NativeReferenceQueue$Lock@2b55402bat java.base@21.0.1/java.lang.Object.wait(Object.java:366)at java.base@21.0.1/java.lang.Object.wait(Object.java:339)at java.base@21.0.1/java.lang.ref.NativeReferenceQueue.await(NativeReferenceQueue.java:48)at java.base@21.0.1/java.lang.ref.ReferenceQueue.remove0(ReferenceQueue.java:158)at java.base@21.0.1/java.lang.ref.NativeReferenceQueue.remove(NativeReferenceQueue.java:89)at java.base@21.0.1/java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:173)

例:
thread --state WAITING ：查看线程中处于等待状态的线程

3、jvm

与JVM相关的信息

[arthas@14156]$ jvmRUNTIME
-----------------------------------------------------------------------------------------------------------------------MACHINE-NAME                      14156@lwzoozycJVM-START-TIME                    2023-11-13 23:10:24MANAGEMENT-SPEC-VERSION           4.0SPEC-NAME                         Java Virtual Machine SpecificationSPEC-VENDOR                       Oracle CorporationSPEC-VERSION                      21VM-NAME                           Java HotSpot(TM) 64-Bit Server VMVM-VENDOR                         Oracle CorporationVM-VERSION                        21.0.1+12-LTS-29INPUT-ARGUMENTS                   []CLASS-PATH                        math-game.jarBOOT-CLASS-PATHLIBRARY-PATH                      C:\Program Files\Java\jdk-21\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:\Program Files\Common Files\Oracle\Java\javapath;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Program Files\NVIDIA Corporation\NVIDIA NvDLISR;"C:\Program Files\Java\jdk-21\bin;C:\Program Files\Java\jdk-21\jre\bin;";C:\Program Files\Go\bin;C:\Program Files\Go\bin;C:\Program Files\PuTTY\;C:\Program Files\Git\cmd;C:\Program Files\TortoiseGit\bin;C:\Program Files\Microsoft VSCode\bin;C:\Program Files\Java\jdk-21\bin;C:\Users\Administrator\AppData\Local\Microsoft\WindowsApps;C:\Users\Administrator\go\bin;C:\Program Files\JetBrains\GoLand 2023.2\bin;;C:\Program Files\JetBrains\IntelliJ IDEA 2023.2.3\bin;;.-----------------------------------------------------------------------------------------------------------------------CLASS-LOADING
-----------------------------------------------------------------------------------------------------------------------LOADED-CLASS-COUNT                4623TOTAL-LOADED-CLASS-COUNT          4623UNLOADED-CLASS-COUNT              0IS-VERBOSE                        false-----------------------------------------------------------------------------------------------------------------------COMPILATION
-----------------------------------------------------------------------------------------------------------------------NAME                              HotSpot 64-Bit Tiered CompilersTOTAL-COMPILE-TIME                3011[time (ms)]-----------------------------------------------------------------------------------------------------------------------GARBAGE-COLLECTORS
-----------------------------------------------------------------------------------------------------------------------G1 Young Generation               name : G1 Young Generation[count/time (ms)]                 collectionCount : 1collectionTime : 11G1 Concurrent GC                  name : G1 Concurrent GC[count/time (ms)]                 collectionCount : 0collectionTime : 0G1 Old Generation                 name : G1 Old Generation[count/time (ms)]                 collectionCount : 0collectionTime : 0-----------------------------------------------------------------------------------------------------------------------MEMORY-MANAGERS
-----------------------------------------------------------------------------------------------------------------------CodeCacheManager                  CodeHeap 'non-nmethods'CodeHeap 'profiled nmethods'CodeHeap 'non-profiled nmethods'Metaspace Manager                 MetaspaceCompressed Class SpaceG1 Young Generation               G1 Eden SpaceG1 Survivor SpaceG1 Old GenG1 Concurrent GC                  G1 Old GenG1 Old Generation                 G1 Eden SpaceG1 Survivor SpaceG1 Old Gen-----------------------------------------------------------------------------------------------------------------------MEMORY
-----------------------------------------------------------------------------------------------------------------------HEAP-MEMORY-USAGE                 init : 1073741824(1.0 GiB)[memory in bytes]                 used : 27318272(26.1 MiB)committed : 1073741824(1.0 GiB)max : 17146314752(16.0 GiB)NO-HEAP-MEMORY-USAGE              init : 7667712(7.3 MiB)[memory in bytes]                 used : 31832208(30.4 MiB)committed : 36438016(34.8 MiB)max : -1(-1 B)PENDING-FINALIZE-COUNT            0-----------------------------------------------------------------------------------------------------------------------OPERATING-SYSTEM
-----------------------------------------------------------------------------------------------------------------------OS                                Windows 10ARCH                              amd64PROCESSORS-COUNT                  36LOAD-AVERAGE                      -1.0VERSION                           10.0-----------------------------------------------------------------------------------------------------------------------THREAD
-----------------------------------------------------------------------------------------------------------------------COUNT                             16DAEMON-COUNT                      15PEAK-COUNT                        16STARTED-COUNT                     19DEADLOCK-COUNT                    0-----------------------------------------------------------------------------------------------------------------------FILE-DESCRIPTOR
-----------------------------------------------------------------------------------------------------------------------MAX-FILE-DESCRIPTOR-COUNT         -1OPEN-FILE-DESCRIPTOR-COUNT        -1

4、sysprop

sysprop：查看和修改JVM的系统属性

[arthas@14156]$ syspropKEY                     VALUE
-----------------------------------------------------------------------------------------------------------------------java.specification.ver  21sionsun.cpu.isalist         amd64sun.jnu.encoding        GBKjava.class.path         math-game.jarjava.vm.vendor          Oracle Corporationsun.arch.data.model     64user.variantjava.vendor.url         https://java.oracle.com/user.timezone           Asia/Shanghaijava.vm.specification.  21versionos.name                 Windows 10sun.java.launcher       SUN_STANDARDuser.country            CNsun.boot.library.path   C:\Program Files\Java\jdk-21\binsun.java.command        math-game.jarjdk.debug               releasesun.cpu.endian          littleuser.home               C:\Users\Administratoruser.language           zhjava.specification.ven  Oracle Corporationdorjava.version.date       2023-10-17java.home               C:\Program Files\Java\jdk-21file.separator          \java.vm.compressedOops  Zero basedModejava.vm.specification.  Oracle Corporationvendorjava.specification.nam  Java Platform API Specificationeuser.scriptsun.management.compile  HotSpot 64-Bit Tiered Compilersrjava.runtime.version    21.0.1+12-LTS-29user.name               Administratorstdout.encoding         ms936path.separator          ;os.version              10.0java.runtime.name       Java(TM) SE Runtime Environmentfile.encoding           UTF-8java.vm.name            Java HotSpot(TM) 64-Bit Server VMjava.vendor.url.bug     https://bugreport.java.com/bugreport/java.io.tmpdir          C:\Users\ADMINI~1\AppData\Local\Temp\java.version            21.0.1user.dir                C:\Users\Administrator\.arthas\lib\3.7.1\arthasos.arch                 amd64java.vm.specification.  Java Virtual Machine Specificationnamesun.os.patch.levelnative.encoding         GBKjava.library.path       C:\Program Files\Java\jdk-21\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:\Program Files\Common Files\Oracle\Java\javapath;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Program Files\NVIDIA Corporation\NVIDIA NvDLISR;"C:\Program Files\Java\jdk-21\bin;C:\Program Files\Java\jdk-21\jre\bin;";C:\Program Files\Go\bin;C:\Program Files\Go\bin;C:\Program Files\PuTTY\;C:\Program Files\Git\cmd;C:\Program Files\TortoiseGit\bin;C:\Program Files\Microsoft VS Code\bin;C:\Program Files\Java\jdk-21\bin;C:\Users\Administrator\AppData\Local\Microsoft\WindowsApps;C:\Users\Administrator\go\bin;C:\Program Files\JetBrains\GoLand 2023.2\bin;;C:\Program Files\JetBrains\IntelliJ IDEA 2023.2.3\bin;;.java.vm.info            mixed mode, sharingstderr.encoding         ms936java.vendor             Oracle Corporationjava.vm.version         21.0.1+12-LTS-29sun.io.unicode.encodin  UnicodeLittlegjava.class.version      65.0
[arthas@14156]$

查看单个属性
[arthas@14156]$ sysprop java.versionKEY                     VALUE
------------------------------------------------------------------------------------------java.version            21.0.1
[arthas@14156]$
修改单个属性
[arthas@14156]$ sysprop user.countryKEY                     VALUE
------------------------------------------------------------------------------------------user.country            CN
[arthas@14156]$ sysprop user.country US
Successfully changed the system property.KEY                     VALUE
------------------------------------------------------------------------------------------user.country            US
[arthas@14156]$ sysprop user.country CN
Successfully changed the system property.KEY                     VALUE
------------------------------------------------------------------------------------------user.country            CN
[arthas@14156]$