Java:故障排查、JVM性能監(jiān)控工具單

常用命令

1、jps：JVM進(jìn)程狀態(tài)工具

usage: jps [-help]       jps [-q] [-mlvV] [<hostid>]Definitions:    <hostid>:      <hostname>[:<port>]

執(zhí)行案例：

jps -l1228 sun.tools.jps.Jps

option參數(shù)說明：

• -q:輸出本地虛擬機(jī)進(jìn)程的ID，省略類名稱。
• -m:輸出啟動(dòng)時(shí)傳遞給主類main()方法的參數(shù)。
• -l:輸出全類名，如果執(zhí)行的是JAR包，會(huì)輸出JAR包路徑。
• -v:輸出進(jìn)程的JVM配置參數(shù)。

2、jstat：JVM統(tǒng)計(jì)信息監(jiān)視工具

jstat幫助文檔：

invalid argument countUsage: jstat -help|-options       jstat -<option> [-t] [-h<lines>] <vmid> [<interval> [<count>]]Definitions:  <option>      An option reported by the -options option  <vmid>        Virtual Machine Identifier. A vmid takes the following form:                     <lvmid>[@<hostname>[:<port>]]                Where <lvmid> is the local vm identifier for the target                Java virtual machine, typically a process id; <hostname> is                the name of the host running the target Java virtual machine;                and <port> is the port number for the rmiregistry on the                target host. See the jvmstat documentation for a more complete                description of the Virtual Machine Identifier.  <lines>       Number of samples between header lines.  <interval>    Sampling interval. The following forms are allowed:                    <n>["ms"|"s"]                Where <n> is an integer and the suffix specifies the units as                 milliseconds("ms") or seconds("s"). The default units are "ms".  <count>       Number of samples to take before terminating.  -J<flag>      Pass <flag> directly to the runtime system.

執(zhí)行案例：

//查看垃圾收集等信息jstat -gc 1441 S0C    S1C    S0U    S1U      EC       EU        OC         OU       MC     MU    CCSC   CCSU   YGC     YGCT    FGC    FGCT     GCT   10752.0 10752.0  0.0    0.0   65536.0   9175.5   175104.0     0.0     4480.0 780.7  384.0   76.6       0    0.000   0      0.000    0.000

option參數(shù)說明：

• -class：監(jiān)視類加載、卸載數(shù)量、總空間以及類裝載的耗時(shí)。
• -compiler：即時(shí)編譯器編譯過的方法、耗時(shí)等信息。
• -gc：監(jiān)視Java堆狀態(tài)，包括Eden區(qū)、兩個(gè)Survivor區(qū)、老年代、永久代的容量、已用空間、垃圾收集時(shí)間合計(jì)等信息。
• -gccapacity：內(nèi)容與gc基本類似，但輸出的主要是關(guān)注Java堆各個(gè)區(qū)域使用的最大、最小空間。
• -gccause：與gcutil功能一樣，但是會(huì)額外輸出上一次導(dǎo)致垃圾收集產(chǎn)生的原因。
• -gcmetacapacity：JDK8下元數(shù)據(jù)空間統(tǒng)計(jì)。
• -gcnew：監(jiān)視新生代垃圾收集信息。
• -gcnewcapacity：與gcnew類似，輸出使用到的最大、最小空間。
• -gcold：監(jiān)視老年代垃圾收集信息。
• -gcoldcapacity：與gcold類似，輸出使用到的最大、最小空間。
• -gcutil：監(jiān)視內(nèi)容與gc類似，輸出已使用空間占總空間的百分比。
• -printcompilation：輸出已經(jīng)被即時(shí)編譯的方法。
  

3、jinfo：Java配置信息工具

jinfo幫助文檔：

Usage:    jinfo [option] <pid>        (to connect to running process)    jinfo [option] <executable <core>        (to connect to a core file)    jinfo [option] [server_id@]<remote server IP or hostname>        (to connect to remote debug server)where <option> is one of:    -flag <name>         to print the value of the named VM flag    -flag [+|-]<name>    to enable or disable the named VM flag    -flag <name>=<value> to set the named VM flag to the given value    -flags               to print VM flags    -sysprops            to print Java system properties    <no option>          to print both of the above    -h | -help           to print this help message

執(zhí)行案例：

jinfo -flags 18378Attaching to process ID 18378, please wait...Debugger attached successfully.Server compiler detected.JVM version is 25.261-b12Non-default VM flags: -XX:CICompilerCount=3 -XX:InitialHeapSize=262144000 -XX:MaxHeapSize=4164943872 -XX:MaxNewSize=1388314624 -XX:MinHeapDeltaBytes=524288 -XX:NewSize=87031808 -XX:OldSize=175112192 -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseParallelGC

option參數(shù)說明：

• no option 輸出全部的參數(shù)和系統(tǒng)屬性。
• -flag name 輸出對(duì)應(yīng)名稱的參數(shù)。
• -flag [+|-]name 開啟或者關(guān)閉對(duì)應(yīng)名稱的參數(shù)。
• -flag name=value 設(shè)定對(duì)應(yīng)名稱的參數(shù)。
• -flags 輸出全部的參數(shù)。
• -sysprops 輸出系統(tǒng)屬性。

4、jmap：Java內(nèi)存映像工具

jmap幫助文檔：

Usage:    jmap [option] <pid>        (to connect to running process)    jmap [option] <executable <core>        (to connect to a core file)    jmap [option] [server_id@]<remote server IP or hostname>        (to connect to remote debug server)where <option> is one of:    <none>               to print same info as Solaris pmap    -heap                to print java heap summary    -histo[:live]        to print histogram of java object heap; if the "live"                         suboption is specified, only count live objects    -clstats             to print class loader statistics    -finalizerinfo       to print information on objects awaiting finalization    -dump:<dump-options> to dump java heap in hprof binary format                         dump-options:                           live         dump only live objects; if not specified,                                        all objects in the heap are dumped.                           format=b     binary format                           file=<file>  dump heap to <file>                         Example: jmap -dump:live,format=b,file=heap.bin <pid>    -F                   force. Use with -dump:<dump-options> <pid> or -histo                         to force a heap dump or histogram when <pid> does not                         respond. The "live" suboption is not supported                         in this mode.    -h | -help           to print this help message    -J<flag>             to pass <flag> directly to the runtime system

執(zhí)行案例：

jmap -dump:format=b,file=test.bin 1713Dumping heap to /Users/handexing/test.bin ...Heap dump file created

option參數(shù)說明：

• -dump:生成Java堆轉(zhuǎn)儲(chǔ)快照。格式為-dump:[live,]format=b,file=<filename>,其中l(wèi)ive參數(shù)說明是否只dump出存活對(duì)象。
• -finalization：顯示在F-queue中等待Finalizer線程執(zhí)行finalize方法的對(duì)象。
• -heap：顯示Java堆詳細(xì)信息。例如哪種回收器、參數(shù)配置、分代情況等。linux平臺(tái)下有效。
• -histo：顯示堆中對(duì)象統(tǒng)計(jì)信息，包括類、實(shí)例數(shù)量等。
• -permstat：以classloader為統(tǒng)計(jì)口徑顯示永久代內(nèi)存狀態(tài)。linux平臺(tái)下有效。
• -F：當(dāng)JVM對(duì)-dump沒有響應(yīng)時(shí)，可以使用-F強(qiáng)制生成dump快照，linux平臺(tái)下有效。

5、jhat：JVM堆轉(zhuǎn)儲(chǔ)快照分析工具

jhat幫助文檔：

Usage:  jhat [-stack <bool>] [-refs <bool>] [-port <port>] [-baseline <file>] [-debug <int>] [-version] [-h|-help] <file>-J<flag>          Pass <flag> directly to the runtime system. For example, -J-mx512m to use a maximum heap size of 512MB-stack false:     Turn off tracking object allocation call stack.-refs false:      Turn off tracking of references to objects-port <port>:     Set the port for the HTTP server.  Defaults to 7000-exclude <file>:  Specify a file that lists data members that should be excluded from the reachableFrom query.-baseline <file>: Specify a baseline object dump.  Objects in both heap dumps with the same ID and same class will be marked as not being "new".-debug <int>:     Set debug level.   0:  No debug output   1:  Debug hprof file parsing   2:  Debug hprof file parsing, no server-version          Report version number-h|-help          Print this help and exit<file>            The file to readFor a dump file that contains multiple heap dumps,you may specify which dump in the fileby appending "#<number>" to the file name, i.e. "foo.hprof#3".All boolean options default to "true"

執(zhí)行案例：

jhat test.bin  Reading from dump.bin...Dump file created Sat Feb 8 21:54:58 CST 2021Snapshot read, resolving...Resolving 271309 objects...Chasing references, expect 54 dots......................................................Eliminating duplicate references......................................................Snapshot resolved.Started HTTP server on port 7000Server is ready.

訪問localhost:7000可以查看分析結(jié)果。

6、jstack：Java堆棧跟蹤工具

Usage:    jstack [-l] <pid>        (to connect to running process)    jstack -F [-m] [-l] <pid>        (to connect to a hung process)    jstack [-m] [-l] <executable> <core>        (to connect to a core file)    jstack [-m] [-l] [server_id@]<remote server IP or hostname>        (to connect to a remote debug server)Options:    -F  to force a thread dump. Use when jstack <pid> does not respond (process is hung)    -m  to print both java and native frames (mixed mode)    -l  long listing. Prints additional information about locks    -h or -help to print this help message

執(zhí)行案例：

jstack -l 17132021-02-08 20:16:16Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.261-b12 mixed mode):"DestroyJavaVM" #53 prio=5 os_prio=31 tid=0x00007fa898808800 nid=0x1103 waiting on condition [0x0000000000000000]   java.lang.Thread.State: RUNNABLE   Locked ownable synchronizers:- None"http-nio-8080-AsyncTimeout" #51 daemon prio=5 os_prio=31 tid=0x00007fa898a4a000 nid=0x7903 waiting on condition [0x0000700007b0b000]   java.lang.Thread.State: TIMED_WAITING (sleeping)at java.lang.Thread.sleep(Native Method)at org.apache.coyote.AbstractProtocol$AsyncTimeout.run(AbstractProtocol.java:1133)at java.lang.Thread.run(Thread.java:748)   Locked ownable synchronizers:- None

option參數(shù)說明：

• -F：正常輸入不被響應(yīng)時(shí)，強(qiáng)制輸出堆棧。
• -m：如果調(diào)用本地方法的話，顯示C/C++的堆棧。
• -l：除堆棧外，顯示關(guān)于鎖的附加信息。
  

Java調(diào)試進(jìn)階工具單

• btrace：https://github.com/btraceio/btrace
• arthas：https://arthas.aliyun.com/doc/
• JProfiler：https://www.ej-technologies.com/products/jprofiler/overview.html