http://www.linuxdiyf.com/linux/18227.html
1、TOP命令，找到占用CPU最高的进程
$ top
top - 20:11:45 up 850 days, 1:18, 3 users, load average: 1.04, 1.01, 0.99
Tasks: 61 total, 1 running, 60 sleeping, 0 stopped, 0 zombie
Cpu(s): 1.4% us, 0.1% sy, 0.0% ni, 98.3% id, 0.1% wa, 0.0% hi, 0.2% si
Mem: 16418172k total, 15693376k used, 724796k free, 1146696k buffers
Swap: 10223608k total,0k used, 10223608k free, 12537692k cached
PID USER PR NI VIRT RES SHR S %CPU %MEMTIME+ COMMAND
24714 ztgame16 0 1409m 1.2g 4252 S 99.6 7.4 2390:57 IMVChannelServe
1 root 16 0 4772 520 432 S 0.0 0.0 0:03.43 init
2 root RT 0 000 S 0.0 0.0 0:05.75 migration/0
3 root 34 19 000 S 0.0 0.0 5:22.97 ksoftirqd/0
4 root RT 0 000 S 0.0 0.0 0:07.90 migration/1
5 root 34 19 000 S 0.0 0.0 0:00.27 ksoftirqd/1
6 root RT 0 000 S 0.0 0.0 0:04.07 migration/2
7 root 34 19 000 S 0.0 0.0 0:00.47 ksoftirqd/2
8 root RT 0 000 S 0.0 0.0 0:04.00 migration/3
9 root 34 19 000 S 0.0 0.0 0:00.33 ksoftirqd/3
2、通过TOP -H -p 进程ID，找到具体的线程占用情况，Shift+H可以开启关闭线程显示
$ top -H -p 24714
top - 20:15:30 up 850 days, 1:22, 3 users, load average: 1.26, 1.09, 1.02
Tasks: 16 total, 1 running, 15 sleeping, 0 stopped, 0 zombie
Cpu(s): 24.8% us, 0.3% sy, 0.0% ni, 73.1% id, 0.0% wa, 0.0% hi, 1.8% si
Mem: 16418172k total, 15701376k used, 716796k free, 1146704k buffers
Swap: 10223608k total,0k used, 10223608k free, 12546048k cached
PID USER PR NI VIRT RES SHR S %CPU %MEMTIME+ COMMAND
24729 ztgame16 0 1409m 1.2g 4252 R 97.0 7.4 2307:22 IMVChannelServe
24721 ztgame15 0 1409m 1.2g 4252 S 2.0 7.4 84:22.40 IMVChannelServe
24714 ztgame16 0 1409m 1.2g 4252 S 0.0 7.4 0:03.80 IMVChannelServe
24716 ztgame15 0 1409m 1.2g 4252 S 0.0 7.4 0:00.00 IMVChannelServe
24717 ztgame15 0 1409m 1.2g 4252 S 0.0 7.4 0:00.04 IMVChannelServe
24718 ztgame15 0 1409m 1.2g 4252 S 0.0 7.4 0:00.00 IMVChannelServe
24719 ztgame15 0 1409m 1.2g 4252 S 0.0 7.4 0:00.08 IMVChannelServe
24720 ztgame15 0 1409m 1.2g 4252 S 0.0 7.4 0:00.01 IMVChannelServe
24722 ztgame15 0 1409m 1.2g 4252 S 0.0 7.4 0:00.00 IMVChannelServe
24723 ztgame16 0 1409m 1.2g 4252 S 0.0 7.4 0:00.00 IMVChannelServe
24724 ztgame15 0 1409m 1.2g 4252 S 0.0 7.4 0:00.01 IMVChannelServe
24725 ztgame15 0 1409m 1.2g 4252 S 0.0 7.4 0:09.83 IMVChannelServe
24726 ztgame15 0 1409m 1.2g 4252 S 0.0 7.4 0:00.00 IMVChannelServe
24727 ztgame15 0 1409m 1.2g 4252 S 0.0 7.4 0:00.76 IMVChannelServe
24728 ztgame16 0 1409m 1.2g 4252 S 0.0 7.4 0:00.53 IMVChannelServe
24730 ztgame16 0 1409m 1.2g 4252 S 0.0 7.4 2:42.18 IMVChannelServe
3、通过命令pstack 进程ID显示线程堆栈，LWP 24729对应线程ID的堆栈，就是占用CPU最高的堆栈，可以具体分析什么原因造成的。
$ pstack 24714
Thread 16 (Thread 1084229984 (LWP 24716)):
#0 0x00000039c5a901d5 in __nanosleep_nocancel () from /lib64/tls/libc.so.6
#1 0x00000039c5ac3058 in usleep () from /lib64/tls/libc.so.6
#2 0x00000000005ebe10 in zVerifyThread::run ()
#3 0x00000000005e9d29 in zThread::threadFunc ()
#4 0x00000039c6106137 in start_thread () from /lib64/tls/libpthread.so.0
#5 0x00000039c5ac9883 in clone () from /lib64/tls/libc.so.6
Thread 15 (Thread 1094719840 (LWP 24717)):
#0 0x00000039c5a901d5 in __nanosleep_nocancel () from /lib64/tls/libc.so.6
#1 0x00000039c5ac3058 in usleep () from /lib64/tls/libc.so.6
#2 0x00000000005ebe10 in zVerifyThread::run ()
#3 0x00000000005e9d29 in zThread::threadFunc ()
#4 0x00000039c6106137 in start_thread () from /lib64/tls/libpthread.so.0
#5 0x00000039c5ac9883 in clone () from /lib64/tls/libc.so.6
Thread 14 (Thread 1105209696 (LWP 24718)):
#0 0x00000039c5a901d5 in __nanosleep_nocancel () from /lib64/tls/libc.so.6
#1 0x00000039c5ac3058 in usleep () from /lib64/tls/libc.so.6
#2 0x00000000005ebe10 in zVerifyThread::run ()
#3 0x00000000005e9d29 in zThread::threadFunc ()
#4 0x00000039c6106137 in start_thread () from /lib64/tls/libpthread.so.0
#5 0x00000039c5ac9883 in clone () from /lib64/tls/libc.so.6
Thread 13 (Thread 1115699552 (LWP 24719)):
#0 0x00000039c5a901d5 in __nanosleep_nocancel () from /lib64/tls/libc.so.6
#1 0x00000039c5ac3058 in usleep () from /lib64/tls/libc.so.6
#2 0x00000000005ebe10 in zVerifyThread::run ()
#3 0x00000000005e9d29 in zThread::threadFunc ()
#4 0x00000039c6106137 in start_thread () from /lib64/tls/libpthread.so.0
#5 0x00000039c5ac9883 in clone () from /lib64/tls/libc.so.6
Thread 3 (Thread 1220598112 (LWP 24729)):
#0 0x00000039c5a71e87 in memset () from /lib64/tls/libc.so.6
#1 0x00000000004fa591 in ChannelTask::forwardToClientByMedia ()
#2 0x0000000000506220 in ChannelTask::parseClientMsg_Normal ()
#3 0x000000000051ef55 in ChannelTask::parseClientMsg ()
#4 0x000000000051f070 in ChannelTask::cmdMsgParse_Forward ()
#5 0x000000000051f1d1 in ChannelTask::cmdMsgParse ()
#6 0x000000000051f414 in ChannelTask::processCmd ()
#7 0x0000000000523ea8 in ChannelTaskManager::processCmd ()
#8 0x0000000000525ddd in ChannelTimeTick::run ()
#9 0x00000000005e9d29 in zThread::threadFunc ()
#10 0x00000039c6106137 in start_thread () from /lib64/tls/libpthread.so.0
#11 0x00000039c5ac9883 in clone () from /lib64/tls/libc.so.6
Thread 2 (Thread 1231087968 (LWP 24730)):
#0 0x00000039c610af8b in __lll_mutex_lock_wait ()
#1 0x0000000000000001 in ?? ()
#2 0x0000000000000065 in ?? ()
#3 0x00000039c6107d87 in pthread_mutex_lock () from /lib64/tls/libpthread.so.0
#4 0x0000003a500ae29e in operator delete () from /usr/lib64/libstdc++.so.6
#5 0x000000000053f59d in ChannelLoadClient::processCmd_DB ()
#6 0x00000000005986c9 in GameAppClient::processTaskCmd_DB ()
#7 0x00000039c5a901e3 in __nanosleep_nocancel () from /lib64/tls/libc.so.6
#8 0x0000000000000000 in ?? ()
Thread 1 (Thread 182894183104 (LWP 24714)):
#0 0x00000039c5ac9c5c in epoll_wait () from /lib64/tls/libc.so.6
#1 0x0000000000620cac in zTCPServer::accept ()
#2 0x00000000005f9c0d in zNetService::serviceCallback ()
#3 0x00000000005f89e3 in zService::main ()
#4 0x0000000000564298 in main ()