java进程CPU过高问题定位

1、top命令查看过高CPU的pid，命令：top

[root@test-v3 bin]# top
top - 16:44:22 up 173 days,  7:05,  2 users,  load average: 0.74, 0.71, 0.61
Tasks: 150 total,   1 running, 149 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.8%us,  0.4%sy,  0.0%ni, 98.1%id,  0.0%wa,  0.0%hi,  0.0%si,  0.7%st
Mem:   8061116k total,  7924856k used,   136260k free,   234996k buffers
Swap:  4194300k total,   383972k used,  3810328k free,  1191756k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                         
  949 root      20   0 3576m 622m 9852 S  3.3  7.9   1194:48 java                                                                             
 5485 root      20   0 3327m 688m 9804 S  3.3  8.8   1769:07 java                                                                             
  980 root      20   0 3460m 692m  10m S  3.0  8.8   1834:53 java                                                                             
 1012 root      20   0 3393m 668m  10m S  3.0  8.5   1824:38 java                                                                             
14017 root      20   0 2841m 393m 9564 S  2.7  5.0   2079:06 java                                                                             
 1042 root      20   0 3522m 725m   9m S  0.7  9.2 366:09.83 java

2、定位线程，命令：ps -mp pid -o THREAD,tid,time | sort -rn

[root@test-v3 bin]# ps -mp 949 -o THREAD,tid,time | sort -rn
USER     %CPU PRI SCNT WCHAN  USER SYSTEM   TID     TIME
root      3.2  19    - futex_    -      - 31587 13:37:04
root      2.5   -    - -         -      -     - 19:55:11
root      0.1  19    - futex_    -      -  1849 01:14:46

3、将线程ID转为 16进制格式，命令：printf "%x\n" tid

[root@test-v3 bin]# printf "%x\n" 31587
7b63

4、打印堆栈信息 ，命令：jstack pid |grep 十六进制格式tid -A 10

其中-A 10表示查找到所在行的后10行。

[root@test-v3 bin]# cd /usr/java/jdk1.7.0_80/bin
[root@test-v3 bin]# ./jstack 949 |grep 7b63 -A 30
"System Clock" daemon prio=10 tid=0x00007f42904b0800 nid=0x7b63 runnable [0x00007f41f6084000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000000eca553a8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:226)
	at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2082)
	at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1090)
	at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:807)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1068)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)

"http-bio-8084-exec-10" daemon prio=10 tid=0x00007f422c011000 nid=0x210 waiting on condition [0x00007f41f6684000]
   java.lang.Thread.State: WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000000ec542870> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
	at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
	at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2043)
	at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442)
	at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:104)
	at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:32)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1068)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)

"http-bio-8084-exec-9" daemon prio=10 tid=0x00007f422c00f800 nid=0x7229 waiting on condition [0x00007f41f6785000]
   java.lang.Thread.State: WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)