arthas

水深无声 2022-11-10 04:58 180阅读 0赞

在[2019年度最受欢迎中国开源软件][2019]看到[jvm调优神器——arthas][jvm_arthas]  
于是安装验证一下，也可参考官方文档[Arthas 用户文档][Arthas]  
在使用之前，先看一个[Linux strace命令][Linux strace]，[你需要知道的16个Linux服务器监控命令  
][16_Linux_]  
执行`strace -ff -o ./bdo -p 23809`,可以查看到进程`23809`中所有线程的内核执行过程，arthas中应该有一些调用linux的基本命令

recvfrom(402, "\0\0\0\2\0\0\0", 7, 0, NULL, NULL) = 7
    ioctl(402, FIONREAD, [0])               = 0
    ioctl(402, FIONREAD, [0])               = 0
    sendto(402, "\36\0\0\0\3select @@session.tx_read_on"..., 34, 0, NULL, 0) = 34
    ioctl(402, FIONREAD, [0])               = 0
    recvfrom(402, "\1\0\0\1", 4, 0, NULL, NULL) = 4
    ioctl(402, FIONREAD, [73])              = 0
    recvfrom(402, "\1,\0\0\2\3def\0\0\0\26@@session.tx_read_o"..., 73, 0, NULL, NULL) = 73
    ioctl(402, FIONREAD, [0])               = 0
    ioctl(402, FIONREAD, [0])               = 0
    sendto(402, "#\0\0\0\3set session transaction rea"..., 39, 0, NULL, 0) = 39
    ioctl(402, FIONREAD, [0])               = 0
    recvfrom(402, "\7\0\0\1", 4, 0, NULL, NULL) = 4
    ioctl(402, FIONREAD, [7])               = 0
    recvfrom(402, "\0\0\0\2\0\0\0", 7, 0, NULL, NULL) = 7
    ioctl(402, FIONREAD, [0])               = 0
    write(330, "\1", 1)                     = 1
    futex(0x7f97e95d7a24, FUTEX_WAIT_BITSET_PRIVATE, 59475, {57557167, 192371664}, ffffffff) = 0
    futex(0x7f97e95d79f8, FUTEX_WAIT_PRIVATE, 2, NULL) = -1 EAGAIN (Resource temporarily unavailable)
    futex(0x7f97e95d79f8, FUTEX_WAKE_PRIVATE, 1) = 0
    write(1, "2021-03-16 12:27:14.395 INFO  c."..., 93) = 93
    write(308, "12:27:14.395 INFO  c.b.f.o.s.han"..., 76) = 76
    write(1, "2021-03-16 12:27:14.396 INFO  c."..., 101) = 101

下面是arthas的基本引用

[root@bg2 app]# curl -O https://alibaba.github.io/arthas/arthas-boot.jar
      % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                     Dload  Upload   Total   Spent    Left  Speed
    100  135k  100  135k    0     0  89227      0  0:00:01  0:00:01 --:--:-- 89269
    [root@bg2 app]# ll
    total 140
    -rw-r--r-- 1 root root 138993 Mar 16 11:23 arthas-boot.jar
    drwxr-xr-x 7   10  143   4096 Jul  7  2018 jdk1.8.0_181
    [root@bg2 app]# java -jar arthas-boot.jar
    [INFO] arthas-boot version: 3.4.5
    [INFO] Found existing java process, please choose one and input the serial number of the process, eg : 1. Then hit ENTER.
    * [1]: 5280 org.apache.ambari.server.controller.AmbariServer
      [2]: 992 org.tanukisoftware.wrapper.WrapperSimpleApp
      [3]: 9477 org.apache.hadoop.hdfs.server.namenode.NameNode
      [4]: 25895 org.apache.livy.server.LivyServer
      [5]: 28007 org.apache.spark.deploy.history.HistoryServer
      [6]: 19755 org.apache.hadoop.yarn.server.nodemanager.NodeManager
      [7]: 24046 org.apache.hadoop.util.RunJar
      [8]: 12848 org.apache.hadoop.hbase.master.HMaster
      [9]: 14704 org.apache.phoenix.queryserver.server.QueryServer
      [10]: 26421 org.apache.hadoop.util.RunJar
      [11]: 8822 
      [12]: 16505 org.apache.hadoop.hbase.thrift2.ThriftServer
      [13]: 14303 org.apache.hadoop.hbase.regionserver.HRegionServer
    
    ########################## 因为ambari是python的程序，所以这里会报错
    1  
    [INFO] Start download arthas from remote server: https://arthas.aliyun.com/download/3.5.0?mirror=aliyun
    [INFO] Download arthas success.
    [INFO] arthas home: /root/.arthas/lib/3.5.0/arthas
    [INFO] Try to attach process 5280
    [ERROR] Start arthas failed, exception stack trace: 
    com.sun.tools.attach.AttachNotSupportedException: Unable to open socket file: target process not responding or HotSpot VM not loaded
            at sun.tools.attach.LinuxVirtualMachine.<init>(LinuxVirtualMachine.java:106)
            at sun.tools.attach.LinuxAttachProvider.attachVirtualMachine(LinuxAttachProvider.java:78)
            at com.sun.tools.attach.VirtualMachine.attach(VirtualMachine.java:250)
            at com.taobao.arthas.core.Arthas.attachAgent(Arthas.java:99)
            at com.taobao.arthas.core.Arthas.<init>(Arthas.java:26)
            at com.taobao.arthas.core.Arthas.main(Arthas.java:137)
    [ERROR] attach fail, targetPid: 5280

没找到socket file就提示下面的异常

[ERROR] Start arthas failed, exception stack trace: 
    com.sun.tools.attach.AttachNotSupportedException: Unable to open socket file: target process not responding or HotSpot VM not loaded
            at sun.tools.attach.LinuxVirtualMachine.<init>(LinuxVirtualMachine.java:106)
            at sun.tools.attach.LinuxAttachProvider.attachVirtualMachine(LinuxAttachProvider.java:78)
            at com.sun.tools.attach.VirtualMachine.attach(VirtualMachine.java:250)
            at com.taobao.arthas.core.Arthas.attachAgent(Arthas.java:99)
            at com.taobao.arthas.core.Arthas.<init>(Arthas.java:26)
            at com.taobao.arthas.core.Arthas.main(Arthas.java:137)
    [ERROR] attach fail, targetPid: 28007

将arthas与进程`bdo.jar`进行关联成功，进入到arthas的交互环境

[root@bwsc52 application]# java -jar arthas-boot.jar
    [INFO] arthas-boot version: 3.4.5
    [INFO] Found existing java process, please choose one and input the serial number of the process, eg : 1. Then hit ENTER.
    * [1]: 23809 bdo.jar
    1
    [INFO] Start download arthas from remote server: https://arthas.aliyun.com/download/3.5.0?mirror=aliyun
    [INFO] File size: 12.22 MB, downloaded size: 2.15 MB, downloading ...
    [INFO] File size: 12.22 MB, downloaded size: 6.23 MB, downloading ...
    [INFO] File size: 12.22 MB, downloaded size: 8.70 MB, downloading ...
    [INFO] File size: 12.22 MB, downloaded size: 11.60 MB, downloading ...
    [INFO] Download arthas success.
    [INFO] Download arthas success.
    [INFO] arthas home: /root/.arthas/lib/3.5.0/arthas
    [INFO] Try to attach process 23809
    [INFO] Attach process 23809 success.
    [INFO] arthas-client connect 127.0.0.1 3658
      ,---.  ,------. ,--------.,--.  ,--.  ,---.   ,---.                           
     /  O  \ |  .--. ''--.  .--'| '--' | / O \ '   .-'                          
    |  .-.  ||  '--'.'   |  |   |  .--.  ||  .-.  |`.  `-.                          
    |  | |  ||  |\  \    |  |   |  |  |  ||  | |  |.-'    |                         
    `--' `--'`--' '--' `--'   `--' `--'`--' `--'`-----'                          
                                                                                    
    
    wiki       https://arthas.aliyun.com/doc                                        
    tutorials  https://arthas.aliyun.com/doc/arthas-tutorials.html                  
    version    3.5.0                                                                
    main_class                                                                      
    pid        23809                                                                
    time       2021-03-16 11:35:42 
    [arthas@23809]$

查看cpu的使用`thread`，从下图看是正常的

[arthas@23809]$ thread
    Threads Total: 870, NEW: 0, RUNNABLE: 58, BLOCKED: 0, WAITING: 755, TIMED_WAITING: 47, TERMINATED: 0, Internal threads: 10                            
    ID    NAME                                  GROUP              PRIORITY    STATE        %CPU        DELTA_TIME   TIME        INTERRUPTED  DAEMON      
    23826 arthas-command-execute                system             5           RUNNABLE     24.08       0.239        0:0.488     false        true        
    -1    C2 CompilerThread0                    -                  -1          -            0.9         0.009        7:23.236    false        true        
    63    redisson-netty-4-5                    main               5           RUNNABLE     0.74        0.007        528:19.124  false        false       
    -1    C1 CompilerThread2                    -                  -1          -            0.46        0.004        4:24.470    false        true        
    23    Thread-7                              system             9           WAITING      0.45        0.004        3:15.760    false        true        
    24    SimplePauseDetectorThread_0           system             9           TIMED_WAITIN 0.32        0.003        92:31.434   false        true        
    58    pool-12-thread-1                      main               5           TIMED_WAITIN 0.17        0.001        96:36.543   false        false       
    59    redisson-netty-4-1                    main               5           RUNNABLE     0.15        0.001        36:54.021   false        false       
    60    redisson-netty-4-2                    main               5           RUNNABLE     0.13        0.001        49:41.481   false        false       
    25    elasticsearch[_client_][[timer]]      main               5           TIMED_WAITIN 0.11        0.001        64:34.247   false        true        
    64    redisson-netty-4-6                    main               5           RUNNABLE     0.1         0.001        40:56.540   false        false       
    40    elasticsearch[_client_][[timer]]      main               5           TIMED_WAITIN 0.09        0.000        64:56.965   false        true        
    35    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.07        0.000        68:55.662   false        true        
    61    redisson-netty-4-3                    main               5           RUNNABLE     0.07        0.000        40:9.429    false        false       
    771   Abandoned connection cleanup thread   main               5           TIMED_WAITIN 0.06        0.000        132:16.994  false        true        
    867   SystemTimer                           main               1           TIMED_WAITIN 0.05        0.000        640:51.449  false        true        
    863   pool-37-thread-1{Hashed wheel timer # main               5           TIMED_WAITIN 0.04        0.000        93:9.247    false        false       
    824   SimplePauseDetectorThread_2           main               5           TIMED_WAITIN 0.04        0.000        465:31.486  false        true        
    32    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.04        0.000        85:44.849   false        true        
    -1    VM Periodic Task Thread               -                  -1          -            0.03        0.000        143:42.067  false        true        
    822   SimplePauseDetectorThread_0           main               5           TIMED_WAITIN 0.03        0.000        459:42.045  false        true        
    65    redisson-netty-4-7                    main               5           RUNNABLE     0.02        0.000        40:4.071    false        false       
    36    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.02        0.000        69:52.316   false        true        
    823   SimplePauseDetectorThread_1           main               5           TIMED_WAITIN 0.02        0.000        456:44.616  false        true        
    62    redisson-netty-4-4                    main               5           RUNNABLE     0.02        0.000        38:57.459   false        false       
    42    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.02        0.000        108:58.594  false        true        
    30    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.02        0.000        95:29.021   false        true        
    28    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.01        0.000        76:42.378   false        true        
    50    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.01        0.000        64:35.136   false        true        
    34    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.01        0.000        73:10.340   false        tr

查看线程是否存在死锁,这里没有出现这个情况

[arthas@23809]$  thread -b
    No most blocking thread found!

如果发生内存泄露，则调用`dashboard`命令进行查看,下面没有看到`BLOCKED`状态的线程，就可以不用管了。

dashboard
    ID    NAME                                  GROUP              PRIORITY    STATE        %CPU        DELTA_TIME   TIME        INTERRUPTED  DAEMON      
    867   SystemTimer                           main               1           TIMED_WAITIN 0.0         0.000        640:54.165  false        true        
    -1    VM Thread                             -                  -1          -            0.0         0.000        588:37.784  false        true        
    63    redisson-netty-4-5                    main               5           RUNNABLE     0.0         0.000        528:25.859  false        false       
    824   SimplePauseDetectorThread_2           main               5           TIMED_WAITIN 0.0         0.000        465:33.064  false        true        
    822   SimplePauseDetectorThread_0           main               5           TIMED_WAITIN 0.0         0.000        459:43.597  false        true        
    823   SimplePauseDetectorThread_1           main               5           TIMED_WAITIN 0.0         0.000        456:46.142  false        true        
    826   lettuce-nioEventLoop-6-2              main               5           RUNNABLE     0.0         0.000        392:0.025   false        true        
    -1    VM Periodic Task Thread               -                  -1          -            0.0         0.000        143:43.694  false        true        
    771   Abandoned connection cleanup thread   main               5           TIMED_WAITIN 0.0         0.000        132:18.651  false        true        
    42    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        109:0.027   false        true        
    46    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        102:12.483  false        true        
    58    pool-12-thread-1                      main               5           TIMED_WAITIN 0.0         0.000        96:37.703   false        false       
    44    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        96:15.539   false        true        
    30    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        95:29.943   false        true        
    863   pool-37-thread-1{Hashed wheel timer # main               5           TIMED_WAITIN 0.0         0.000        93:10.358   false        false       
    836   pool-35-thread-1{Hashed wheel timer # main               5           TIMED_WAITIN 0.0         0.000        93:1.143    false        false       
    24    SimplePauseDetectorThread_0           system             9           TIMED_WAITIN 0.0         0.000        92:32.502   false        true        
    47    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        90:23.412   false        true        
    31    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        89:10.260   false        true        
    33    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        86:56.440   false        true        
    32    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        85:45.674   false        true        
    45    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        81:21.415   false        true        
    28    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        76:43.069   false        true        
    34    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        73:11.123   false        true        
    48    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        70:32.459   false        true        
    36    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        69:52.974   false        true        
    35    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        68:56.311   false        true        
    40    elasticsearch[_client_][[timer]]      main               5           TIMED_WAITIN 0.0         0.000        64:57.801   false        true        
    50    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        64:35.837   false        true        
    25    elasticsearch[_client_][[timer]]      main               5           TIMED_WAITIN 0.0         0.000        64:34.984   false        true        
    49    elasticsearch[_client_][transport_cli main               5           RUNNABLE     0.0         0.000        64:11.541   false        true        
    835   Avro NettyTransceiver I/O Worker 8{Ne main               5           RUNNABLE     0.0         0.000        58:36.468   false        true        
    834   Avro NettyTransceiver I/O Worker 7{Ne main               5           RUNNABLE     0.0         0.000        50:9.839    false        true        
    60    redisson-netty-4-2                    main               5           RUNNABLE     0.0         0.000        49:42.133   false        false       
    828   Avro NettyTransceiver I/O Worker 1{Ne main               5           RUNNABLE     0.0         0.000        48:18.746   false        true        
    Memory                          used       total      max       usage      GC                                                                         
    heap                            384M       783M       843M      45.65%     gc.ps_scavenge.count                  21462                                
    ps_eden_space                   77M        294M       300M      25.67%     gc.ps_scavenge.time(ms)               2003799                              
    ps_survivor_space               4M         4M         4M        91.06%     gc.ps_marksweep.count                 10                                   
    ps_old_gen                      303M       485M       632M      48.03%     gc.ps_marksweep.time(ms)              6320                                 
    nonheap                         190M       242M       -1        78.50%                                                                                
    code_cache                      35M        77M        240M      14.61%                                                                                
    metaspace                       138M       146M       -1        94.52%                                                                                
    compressed_class_space          17M        18M        1024M     1.67%                                                                                 
    direct                          131M       131M       -         100.00%                                                                               
    mapped                          0K         0K         -         0.00%                                                                                 
    Runtime                                                                                                                                               
    os.name                                                                    Linux                                                                      
    os.version                                                                 3.10.0-327.el7.x86_64                                                      
    java.version                                                               1.8.0_151                                                                  
    java.home                                                                  /usr/java/jdk1.8.0_151/jre                                                 
    systemload.average                                                         0.28                                                                       
    processors                                                                 4                                                                          
    timestamp/uptime                                                           Tue Mar 16 11:46:58 CST 2021/9650054s

下载内存快照

[arthas@23809]$ heapdump --live /root/jvm.hprof
    Dumping heap to /root/jvm.hprof ...
    Heap dump file created

这里照着《java并发编程的艺术》，写一个死锁的例子

public class DeadLockDemo { 
        private static String A = "A";
        private static String B = "B";
    
        public static void main(String[] args) { 
            new DeadLockDemo().deadLock();
        }
    
        private void deadLock() { 
            Thread t1 = new Thread(new Runnable() { 
                @Override
                public void run() { 
                    synchronized (A) { 
                        try { 
                            Thread.currentThread().sleep(2000);
                        } catch (InterruptedException e) { 
                            e.printStackTrace();
                        }
                        synchronized (B) { 
                            System.out.println("1");
                        }
                    }
                }
            });
            Thread t2 = new Thread(new Runnable() { 
                @Override
                public void run() { 
                    synchronized (B) { 
                        synchronized (A) { 
                            System.out.println("2");
                        }
                    }
                }
            });
            t1.start();
            t2.start();
        }
    }

执行`java -cp threads-1.0.jar com.dzmsoft.thhreads.one.DeadLockDemo`,可以看到两个两个进程死锁，根据进程号，定位问题在哪里。  
![1][]  
现在我们介绍避免死锁的几个常见方法。 ·避免一个线程同时获取多个锁。 ·避免一个线程在锁内同时占用多个资源，尽量保证每个锁只占用一个资源。 ·尝试使用定时锁，使用lock.tryLock（timeout）来替代使用内部锁机制。 ·对于数据库锁，加锁和解锁必须在一个数据库连接里，否则会出现解锁失败的情况

[2019]: https://www.oschina.net/project/top_cn_2019
[jvm_arthas]: https://www.cnblogs.com/spareyaya/p/13177513.html
[Arthas]: http://arthas.gitee.io/
[Linux strace]: https://www.cnblogs.com/ggjucheng/archive/2012/01/08/2316692.html
[16_Linux_]: https://my.oschina.net/Rayn/blog/349378
[1]: https://img-blog.csdnimg.cn/20210428185459297.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhcnJhaA==,size_16,color_FFFFFF,t_70