使用jstack分析java程序cpu占用率过高的有关问题
使用jstack分析java程序cpu占用率过高的问题
1，使用jps查找出java进程的pid，如3707
2，使用top -p 14292 -H观察该进程中所有线程的CPU占用。
[[email protected] ~]# top -p 14292 -H top - 22:14:13 up 33 days, 7:29, 4 users, load average: 25.68, 32.11, 33.76 Tasks: 113 total, 2 running, 111 sleeping, 0 stopped, 0 zombie Cpu(s): 68.3%us, 6.3%sy, 0.0%ni, 20.2%id, 0.1%wa, 0.2%hi, 4.9%si, 0.0%st Mem: 65965312k total, 65451232k used, 514080k free, 82164k buffers Swap: 975864k total, 972052k used, 3812k free, 9714400k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 15844 root 15 0 6889m 5.7g 4864 S 20.6 9.1 814:13.29 java 15848 root 15 0 6889m 5.7g 4864 S 13.0 9.1 460:25.17 java 15611 root 15 0 6889m 5.7g 4864 S 12.7 9.1 468:17.77 java 15613 root 15 0 6889m 5.7g 4864 S 11.7 9.1 479:40.45 java 15743 root 15 0 6889m 5.7g 4864 S 11.7 9.1 443:04.80 java 15612 root 15 0 6889m 5.7g 4864 S 11.0 9.1 453:43.68 java 15965 root 15 0 6889m 5.7g 4864 S 10.3 9.1 371:00.33 java 15490 root 15 0 6889m 5.7g 4864 S 7.7 9.1 255:32.74 java 15587 root 15 0 6889m 5.7g 4864 S 7.3 9.1 282:27.58 java 15590 root 15 0 6889m 5.7g 4864 S 7.3 9.1 205:48.37 java 15491 root 15 0 6889m 5.7g 4864 R 6.3 9.1 279:09.08 java 15689 root 15 0 6889m 5.7g 4864 S 5.7 9.1 251:42.36 java 16935 root 15 0 6889m 5.7g 4864 S 5.7 9.1 190:34.37 java 15665 root 15 0 6889m 5.7g 4864 S 5.3 9.1 250:07.34 java 16920 root 15 0 6889m 5.7g 4864 S 5.3 9.1 241:34.50 java 15671 root 15 0 6889m 5.7g 4864 S 5.0 9.1 239:49.97 java 15492 root 15 0 6889m 5.7g 4864 S 4.7 9.1 210:23.09 java 14322 root 16 0 6889m 5.7g 4864 S 4.3 9.1 107:39.61 java 14316 root 16 0 6889m 5.7g 4864 S 4.0 9.1 107:18.43 java 14317 root 16 0 6889m 5.7g 4864 S 4.0 9.1 107:29.13 java 15591 root 15 0 6889m 5.7g 4864 S 4.0 9.1 114:34.90 java 14313 root 16 0 6889m 5.7g 4864 S 3.7 9.1 107:12.70 java 14314 root 15 0 6889m 5.7g 4864 S 3.7 9.1 107:28.05 java 14319 root 16 0 6889m 5.7g 4864 S 3.7 9.1 107:27.43 java 14321 root 15 0 6889m 5.7g 4864 S 3.3 9.1 108:01.12 java 15589 root 15 0 6889m 5.7g 4864 R 3.0 9.1 109:01.91 java 15615 root 15 0 6889m 5.7g 4864 S 3.0 9.1 114:55.29 java 16808 root 15 0 6889m 5.7g 4864 S 2.7 9.1 279:05.03 java 14315 root 15 0 6889m 5.7g 4864 S 2.0 9.1 107:45.00 java 14320 root 15 0 6889m 5.7g 4864 S 2.0 9.1 107:48.30 java 15489 root 15 0 6889m 5.7g 4864 S 1.7 9.1 57:38.46 java 15670 root 15 0 6889m 5.7g 4864 S 1.3 9.1 5:55.43 java 14318 root 15 0 6889m 5.7g 4864 S 0.7 9.1 107:45.88 java 14826 root 15 0 6889m 5.7g 4864 S 0.7 9.1 25:07.64 java
3，找出CPU消耗较多的线程id，如15844，将15844转换为16进制0x3de4，注意是小写哦
4，使用jstack 14292|grep -A 10 0x3de4来查询出具体的线程状态。
[[email protected] ~]# jstack 14292|grep -A 10 0x3de4 "pool-52-thread-1" prio=10 tid=0x000000005a08e000 nid=0x3de4 waiting on condition [0x00002ae63d917000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000006f9a0a110> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:947) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907) at java.lang.Thread.run(Thread.java:662)
通过这些线程状态便可基本定位问题之所在。