重点是查看进程的线程中，哪个线程占用cpu过高，然后用gdb附加到进程，调试线程，看是否有死循环或者死锁等问题，步骤如下： 

先用ps + grep找出该死的进程pid，比如 1706

然后 top -H -p 1706，(top然后shift+H可以看出某个线程，左上角有提示：thread on 则为可查看线程)所有该进程的线程都列出来， 看看哪个线程pid占用最多，记下对应的线程号，如：1723

1.gdb attach 到进程号码（1706）

2.（仍然在gdb中） info threads 结果大致如下：

(gdb) info threads   8 Thread 0x7f9fa9366700 (LWP 1716)  0x0000003cec00b98e in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0   7 Thread 0x7f9fa8965700 (LWP 1720)  0x0000003cec00b98e in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0   6 Thread 0x7f9fa7f64700 (LWP 1721)  0x0000003cec00f4b5 in sigwait ()    from /lib64/libpthread.so.0   5 Thread 0x7f9fa7563700 (LWP 1722)  0x0000003cec00b98e in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0   4 Thread 0x7f9fa6b62700 (LWP 1723)  0x0000003cec00b5bc in pthread_cond_wait@@GLIBC_2.3.2     () from /lib64/libpthread.so.0   3 Thread 0x7f9fa6161700 (LWP 1724)  0x0000003cebce9163 in epoll_wait ()    from /lib64/libc.so.6   2 Thread 0x7f9fa1159700 (LWP 1887)  0x0000003cebce9163 in epoll_wait ()    from /lib64/libc.so.6 * 1 Thread 0x7f9fa95ad820 (LWP 1706)  0x0000003cec00b5bc in pthread_cond_wait@@GLIBC_2.3.2     () from /lib64/libpthread.so.0

找到线程号码对应的thread（LWP1723）即是我们刚刚记下的线程号

3.（仍然在gdb中）thread 线程号码切换到线程（4）–这里在info threads显示出来的序号需要使用gdb能识别的线程序号，即执行：thread 4切换到我们刚刚记下的线程号：1723的对应线程，如下：

(gdb) thread 4 [Switching to thread 4 (Thread 0x7f9fa6b62700 (LWP 1723))]#0  0x0000003cec00b5bc in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0

4.（仍然在gdb中）bt 查看线程调用堆栈 

(gdb) bt

#0  0x0000003cec00b5bc in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0 #1  0x00007f9fa9f7144d in IceUtil::Cond::waitImpl (this=0x263f4c8,      mutex=...) at ../../include/IceUtil/Cond.h:215 #2  0x00007f9fa9f9a4b1 in IceUtil::Monitor::wait (this=0x263f4c8)     at ../../include/IceUtil/Monitor.h:152 #3  0x00007f9fa9fd7567 in IceInternal::EndpointHostResolver::run (this=0x263f480)     at EndpointI.cpp:161 #4  0x00007f9fa9b1b975 in startHook (arg=0x263f480) at Thread.cpp:413 #5  0x0000003cec0079d1 in start_thread () from /lib64/libpthread.so.0 #6  0x0000003cebce8b6d in clone () from /lib64/libc.so.6

5.从上面输出的信息，基本上可以查看线程对应的代码断，是否有死循环等，如果是死锁的话，需要多次查看当前线程堆栈，或者查看全部线程的堆栈，总是会有某些个线程跟其他线程不一致，然后再对应到代码来进行定位解决