一、jps、jstack命令
jps命令是 查看但其jvm进程、jstatck命令查看进程的线程运行状态情况
[root@iZuf6gyurl0fqb87hirq23Z tomcat7]# jps@b@22919 Jps@b@19871 Bootstrap@b@@b@[root@iZuf6gyurl0fqb87hirq23Z tomcat7]# jstack -l 19871@b@2019-07-15 23:00:32@b@Full thread dump Java HotSpot(TM) 64-Bit Server VM (24.80-b11 mixed mode):@b@...
线程状态说明>
- RUNNABLE 线程运行中或 I/O 等待(可能里面还能看到locked字样，表明它获得了某把锁) @b@- BLOCKED 线程受阻塞并等待( synchronized 关键字) @b@- TIMED_WAITING 线程在等待唤醒，但设置了时限 (和WAITING的区别是wait() 等语句加上了时间限制 wait(timeout))@b@- WAITING 线程在无限等待唤醒(等待某个condition或monitor发生，一般停留在park(), wait(), sleep(),join() 等语句里)@b@- TERMINATED,已退出的。
二、jstat命令
jstat命令实时监控classloader，compiler，gc情况
1. 监控classloader加载情况(每隔1秒监控一次，一共做10次)
[root@iZuf6gyurl0fqb87hirq23Z ~]# jstat -class 19871 1000 10@b@Loaded Bytes Unloaded Bytes Time @b@ 6648 13167.0 9 14.1 8.11@b@ 6648 13167.0 9 14.1 8.11@b@ 6648 13167.0 9 14.1 8.11@b@ 6648 13167.0 9 14.1 8.11@b@ 6648 13167.0 9 14.1 8.11@b@ 6648 13167.0 9 14.1 8.11@b@ 6648 13167.0 9 14.1 8.11@b@ 6648 13167.0 9 14.1 8.11@b@ 6648 13167.0 9 14.1 8.11@b@ 6648 13167.0 9 14.1 8.11
2.监控gc情况(每隔1秒监控一次，一共做10次)
[root@iZuf6gyurl0fqb87hirq23Z ~]# jstat -gcutil 19871 1000 10@b@ S0 S1 E O P YGC YGCT FGC FGCT GCT @b@ 4.62 0.00 37.42 77.32 99.33 4106 33.946 4 2.389 36.335@b@ 4.62 0.00 37.42 77.32 99.33 4106 33.946 4 2.389 36.335@b@ 4.62 0.00 37.42 77.32 99.33 4106 33.946 4 2.389 36.335@b@ 4.62 0.00 37.42 77.32 99.33 4106 33.946 4 2.389 36.335@b@ 4.62 0.00 37.42 77.32 99.33 4106 33.946 4 2.389 36.335@b@ 4.62 0.00 37.42 77.32 99.33 4106 33.946 4 2.389 36.335@b@ 0.00 4.25 56.37 77.32 99.33 4107 33.962 4 2.389 36.351@b@ 0.00 4.25 56.37 77.32 99.33 4107 33.962 4 2.389 36.351@b@ 0.00 4.25 56.42 77.32 99.33 4107 33.962 4 2.389 36.351@b@ 0.00 4.25 56.42 77.32 99.33 4107 33.962 4 2.389 36.351
3.VM实时编译的数量等信息(每隔1秒监控一次，一共做10次)
[root@iZuf6gyurl0fqb87hirq23Z ~]# jstat -compiler 19871 1000 10@b@Compiled Failed Invalid Time FailedType FailedMethod@b@ 2189 2 0 97.58 1 sun/misc/URLClassPath getResource@b@ 2189 2 0 97.58 1 sun/misc/URLClassPath getResource@b@ 2189 2 0 97.58 1 sun/misc/URLClassPath getResource@b@ 2189 2 0 97.58 1 sun/misc/URLClassPath getResource@b@ 2189 2 0 97.58 1 sun/misc/URLClassPath getResource@b@ 2189 2 0 97.58 1 sun/misc/URLClassPath getResource@b@ 2189 2 0 97.58 1 sun/misc/URLClassPath getResource@b@ 2189 2 0 97.58 1 sun/misc/URLClassPath getResource@b@ 2189 2 0 97.58 1 sun/misc/URLClassPath getResource@b@ 2189 2 0 97.58 1 sun/misc/URLClassPath getResource
三、jmap命令
1. 打印堆栈前30条对象class大小详情信息
[root@iZuf6gyurl0fqb87hirq23Z logs]# jmap -histo 15675 | head -30@b@ num #instances #bytes class name@b@----------------------------------------------@b@ 1: 1270387 57606600 [C@b@ 2: 6211 53647944 [I@b@ 3: 40772 48949344 [B@b@ 4: 1254021 30096504 java.lang.String@b@ 5: 560982 22439280 com.webssky.jcseg.Word@b@ 6: 567345 18155040 java.util.concurrent.ConcurrentHashMap$HashEntry@b@ 7: 242874 11657952 java.util.HashMap@b@ 8: 102979 9889112 [Ljava.util.HashMap$Entry;@b@ 9: 289507 9264224 java.util.HashMap$Entry@b@ 10: 57704 8531008 <constMethodKlass>@b@ 11: 57704 7397408 <methodKlass>@b@ 12: 5631 6492744 <constantPoolKlass>@b@ 13: 235429 5650296 com.chenlb.mmseg4j.CharNode$TreeNode@b@ 14: 5631 3968056 <instanceKlassKlass>@b@ 15: 235581 3769296 java.lang.Character@b@ 16: 4486 3497568 <constantPoolCacheKlass>@b@ 17: 1303 3261328 [Ljava.util.concurrent.ConcurrentHashMap$HashEntry;@b@ 18: 19698 1260672 java.net.URL@b@ 19: 24673 986920 java.util.LinkedHashMap$Entry@b@ 20: 12039 855736 [Ljava.lang.Object;@b@ 21: 1265 716904 <methodDataKlass>@b@ 22: 10247 640280 [S@b@ 23: 6054 585136 java.lang.Class@b@ 24: 12001 576048 org.apache.catalina.loader.ResourceEntry@b@ 25: 20114 482736 org.apache.tomcat.util.bcel.classfile.ConstantUtf8@b@ 26: 8785 450296 [[I@b@ 27: 5352 428160 java.lang.reflect.Method@b@ 28: 12715 406880 com.chenlb.mmseg4j.CharNode@b@ 29: 14391 286376 [Ljava.lang.Class;@b@ 30: 10638 255312 java.util.LinkedList$Node
其中：@b@[C is a char[]@b@[S is a short[]@b@[I is a int[]@b@[B is a byte[]@b@[[I is a int[][]
2. 打印堆栈大小占比详情
[root@iZuf6gyurl0fqb87hirq23Z logs]# jmap -heap 15675@b@Attaching to process ID 15675, please wait...@b@Debugger attached successfully.@b@Server compiler detected.@b@JVM version is 24.80-b11@b@@b@using thread-local object allocation.@b@Mark Sweep Compact GC@b@@b@Heap Configuration:@b@ MinHeapFreeRatio = 40@b@ MaxHeapFreeRatio = 70@b@ MaxHeapSize = 1048576000 (1000.0MB)@b@ NewSize = 1310720 (1.25MB)@b@ MaxNewSize = 209715200 (200.0MB)@b@ OldSize = 5439488 (5.1875MB)@b@ NewRatio = 2@b@ SurvivorRatio = 8@b@ PermSize = 21757952 (20.75MB)@b@ MaxPermSize = 85983232 (82.0MB)@b@ G1HeapRegionSize = 0 (0.0MB)@b@@b@Heap Usage:@b@New Generation (Eden + 1 Survivor Space):@b@ capacity = 188743680 (180.0MB)@b@ used = 14213168 (13.554733276367188MB)@b@ free = 174530512 (166.4452667236328MB)@b@ 7.530407375759548% used@b@Eden Space:@b@ capacity = 167772160 (160.0MB)@b@ used = 14213168 (13.554733276367188MB)@b@ free = 153558992 (146.4452667236328MB)@b@ 8.471708297729492% used@b@From Space:@b@ capacity = 20971520 (20.0MB)@b@ used = 0 (0.0MB)@b@ free = 20971520 (20.0MB)@b@ 0.0% used@b@To Space:@b@ capacity = 20971520 (20.0MB)@b@ used = 0 (0.0MB)@b@ free = 20971520 (20.0MB)@b@ 0.0% used@b@tenured generation:@b@ capacity = 838860800 (800.0MB)@b@ used = 264228688 (251.9881134033203MB)@b@ free = 574632112 (548.0118865966797MB)@b@ 31.49851417541504% used@b@Perm Generation:@b@ capacity = 33226752 (31.6875MB)@b@ used = 32992568 (31.46416473388672MB)@b@ free = 234184 (0.22333526611328125MB)@b@ 99.29519442646696% used@b@@b@15245 interned Strings occupying 1949432 bytes.
[root@iZuf6gyurl0fqb87hirq23Z dump]# ps -ef|grep tomcat@b@root 24175 1 60 23:48 pts/2 00:01:59 /home/app/jdk1.7.0_80/jre/bin/java -Djava.util.logging.config.file=/home/app/tomcat7/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -server -Xms300M -Xmx790M -XX:HeapDumpPath=/home/app/tomcat7/logs/dump -XX:ParallelGCThreads=4 -XX:PermSize=50M -XX:MaxPermSize=128M -XX:-DisableExplicitGC -XX:+UseCompressedOops -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled -Dsolr.solr.home=/home/app/tomcat7/bin/solr-md -Djava.endorsed.dirs=/home/app/tomcat7/endorsed -classpath /home/app/tomcat7/bin/bootstrap.jar:/home/app/tomcat7/bin/tomcat-juli.jar -Dcatalina.base=/home/app/tomcat7 -Dcatalina.home=/home/app/tomcat7 -Djava.io.tmpdir=/home/app/tomcat7/temp org.apache.catalina.startup.Bootstrap start@b@@b@[root@iZuf6gyurl0fqb87hirq23Z dump]# jmap -dump:file=/home/app/tomcat7/logs/dump/javaDump.hprof,format=b 24175@b@@b@[root@iZuf6gyurl0fqb87hirq23Z dump]# ls -l@b@@b@total 429188@b@-rw------- 1 root root 439482830 Nov 7 23:51 javaDump.hprof
3. 将当前堆栈信息以二进制格式保存为heap.bytes.data文件（建议通过jdk自带Java VisualVM堆栈查看工具进行装入分析，也可以通过mat工具进行查询分析）
[root@iZuf6gyurl0fqb87hirq23Z logs]# jmap -dump:live,format=b,file=heap.bytes.data 19871@b@Dumping heap to /app/tomcat7/logs/heap.bytes.data20190715 ...@b@Heap dump file created@b@...