生产CPU占用过高，如何分析和定位

1. 线用top命令找出CPU占比最高的
2. ps -ef 或者 jps 进一步定位得知是怎样一个后台程序
3. 定位到具体线程或者代码
4. 将需要的线程id转换位16进制歌是（英文小写）
5. jstack pid | grep tid （16进制线程ID小写英文）-A60

案例

1. top

1. jps -l 或者 ps -ef|grep java|grep -v grep

1. ps -mp 48951 -o THREAD,tid,time 或者 top -Hp 48951

1. printf “%x\n” 48960

1. jstack 48951 | grep bf40 -A60

[silver@localhost ~]$ jstack 48951 | grep bf40 -A60
"VM Periodic Task Thread" os_prio=0 tid=0x00007ff5c00bb000 nid=0xbf40 waiting on condition 
JNI global references: 311
Found one Java-level deadlock:
=============================
"Thread-1":
  waiting to lock monitor 0x00007ff5a40062c8 (object 0x00000000f0c5d458, a java.lang.Object),
  which is held by "Thread-0"
"Thread-0":
  waiting to lock monitor 0x00007ff5a4004e28 (object 0x00000000f0c5d468, a java.lang.Object),
  which is held by "Thread-1"
Java stack information for the threads listed above:
===================================================
"Thread-1":
    at JstackDeadLockDemo.calLock_Obj2_First(JstackDeadLockDemo.java:49)
    - waiting to lock <0x00000000f0c5d458> (a java.lang.Object)
    - locked <0x00000000f0c5d468> (a java.lang.Object)
    at JstackDeadLockDemo.lambda$testDeadlock$1(JstackDeadLockDemo.java:23)
    at JstackDeadLockDemo$$Lambda$2/1418481495.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:748)
"Thread-0":
    at JstackDeadLockDemo.calLock_Obj1_First(JstackDeadLockDemo.java:36)
    - waiting to lock <0x00000000f0c5d468> (a java.lang.Object)
    - locked <0x00000000f0c5d458> (a java.lang.Object)
    at JstackDeadLockDemo.lambda$testDeadlock$0(JstackDeadLockDemo.java:22)
    at JstackDeadLockDemo$$Lambda$1/471910020.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:748)
Found 1 deadlock.