【原创】如何查看某进程下运行的线程
研究 Atlas 过程中，需要了解其进程模型（线程模型），那么如何查看其运行模式呢？
前提：Atlas 配置了 daemon 模式和 keepalive 功能。
[root@Betty conf]# vi modb.cnf [mysql-proxy] ... daemon = true keepalive = true ...
查看方式：
1. ps 命令查看
从 man ps 中可以如下说明，可以显示进程关系，
To print a process tree: ps -ejH ps axjf但 ps -ejH 显示出来的东东比较难看，所以采用第二种方式查看，
[root@Betty conf]# ps axjf|grep mysql-proxy|grep -v grep
1 3755 3754 3754 ? -1 S 0 0:00 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf
3755 3756 3754 3754 ? -1 Sl 0 0:00 \_ mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf
那么如何显示线程关系呢？有如下说明，
To get info about threads: ps -eLf ps axms执行后输出（采用第一种方式查看，原因同上）
[root@Betty conf]# ps -eLf|grep mysql-proxy UID PID PPID LWP C NLWP STIME TTY TIME CMD root 3755 1 3755 0 1 15:14 ? 00:00:00 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 3756 3755 3756 0 5 15:14 ? 00:00:00 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 3756 3755 3757 0 5 15:14 ? 00:00:00 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 3756 3755 3758 0 5 15:14 ? 00:00:00 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 3756 3755 3759 0 5 15:14 ? 00:00:00 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 3756 3755 3760 0 5 15:14 ? 00:00:00 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 4154 18711 4154 0 1 16:32 pts/5 00:00:00 grep mysql-proxy其中
LWP -- 轻量级进程，即线程，这里显示的是 thread id。
NLWP -- 线程数，即 number of threads in process。
如果还想要查看线程究竟运行在哪个 CPU 上，则执行如下命令，
[root@Betty conf]# ps -eo ruser,pid,ppid,lwp,psr,args -L|grep mysql-proxy RUSER PID PPID LWP PSR COMMAND root 3755 1 3755 2 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 3756 3755 3756 1 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 3756 3755 3757 0 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 3756 3755 3758 3 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 3756 3755 3759 1 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 3756 3755 3760 1 mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/modb.cnf root 4162 18711 4162 2 grep mysql-proxy [root@Betty conf]#关键参数说明如下：
To see every process with a user-defined format: ps -eo pid,tid,class,rtprio,ni,pri,psr,pcpu,stat,wchan:14,comm ps axo stat,euid,ruid,tty,tpgid,sess,pgrp,ppid,pid,pcpu,comm ... -L Show threads, possibly with LWP and NLWP columns ... psr PSR processor that process is currently assigned to. ...
2. pstree 命令查看
查看 mysql-proxy 对应的进程 id 。
[root@Betty conf]# ps -e |grep mysql-proxy 3755 ? 00:00:00 mysql-proxy 3756 ? 00:00:00 mysql-proxy分别查看以上两个进程的树形关系。
[root@Betty conf]# pstree 3755
mysql-proxy---mysql-proxy---4*[{mysql-proxy}]
[root@Betty conf]# pstree -p 3756
mysql-proxy(3756)-+-{mysql-proxy}(3757)
|-{mysql-proxy}(3758)
|-{mysql-proxy}(3759)
`-{mysql-proxy}(3760)
[root@Betty conf]#
3. top 命令查看
查看 id 为 3756 的进程包含的线程。
[root@Betty conf]# top -Hp 3756 top - 17:32:19 up 8:26, 6 users, load average: 0.00, 0.00, 0.00 Tasks: 5 total, 0 running, 5 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.0%sy, 0.1%ni, 99.7%id, 0.1%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 3941948k total, 897296k used, 3044652k free, 116232k buffers Swap: 5996536k total, 0k used, 5996536k free, 516676k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 3756 root 15 0 195m 3752 1804 S 0.0 0.1 0:00.00 mysql-proxy 3757 root 15 0 195m 3752 1804 S 0.0 0.1 0:00.00 mysql-proxy 3758 root 15 0 195m 3752 1804 S 0.0 0.1 0:00.00 mysql-proxy 3759 root 15 0 195m 3752 1804 S 0.0 0.1 0:00.00 mysql-proxy 3760 root 15 0 195m 3752 1804 S 0.0 0.1 0:00.00 mysql-proxy按 f 后显示
Current Fields: AEHIOQTWKNMbcdfgjplrsuvyzX for window 1:Def Toggle fields via field letter, type any other key to return * A: PID = Process Id * E: USER = User Name * H: PR = Priority * I: NI = Nice value * O: VIRT = Virtual Image (kb) * Q: RES = Resident size (kb) * T: SHR = Shared Mem size (kb) * W: S = Process Status * K: %CPU = CPU usage * N: %MEM = Memory usage (RES) * M: TIME+ = CPU Time, hundredths b: PPID = Parent Process Pid c: RUSER = Real user name d: UID = User Id f: GROUP = Group Name g: TTY = Controlling Tty j: P = Last used cpu (SMP) p: SWAP = Swapped size (kb) l: TIME = CPU Time r: CODE = Code size (kb) s: DATA = Data+Stack size (kb) u: nFLT = Page Fault count v: nDRT = Dirty Pages count y: WCHAN = Sleeping in Function z: Flags = Task Flags <sched.h> * X: COMMAND = Command name/line Flags field: 0x00000001 PF_ALIGNWARN 0x00000002 PF_STARTING 0x00000004 PF_EXITING 0x00000040 PF_FORKNOEXEC 0x00000100 PF_SUPERPRIV 0x00000200 PF_DUMPCORE 0x00000400 PF_SIGNALED 0x00000800 PF_MEMALLOC 0x00002000 PF_FREE_PAGES (2.5) 0x00008000 debug flag (2.5) 0x00024000 special threads (2.5) 0x001D0000 special states (2.5) 0x00100000 PF_USEDFPU (thru 2.4)按 j 后变化的项为
* J: P = Last used cpu (SMP)按回车或空格保存，退回到 top 界面，显示如下
top - 17:34:07 up 8:27, 6 users, load average: 0.00, 0.00, 0.00 Tasks: 5 total, 0 running, 5 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 3941948k total, 897172k used, 3044776k free, 116264k buffers Swap: 5996536k total, 0k used, 5996536k free, 516676k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND 3756 root 15 0 195m 3752 1804 S 0.0 0.1 0:00.00 1 mysql-proxy 3757 root 15 0 195m 3752 1804 S 0.0 0.1 0:00.00 0 mysql-proxy 3758 root 15 0 195m 3752 1804 S 0.0 0.1 0:00.00 1 mysql-proxy 3759 root 15 0 195m 3752 1804 S 0.0 0.1 0:00.00 1 mysql-proxy 3760 root 15 0 195m 3752 1804 S 0.0 0.1 0:00.00 1 mysql-proxy在 top 的显示中会多出 P 这一列是最近一次运行该线程（进程）的CPU 。
4. 到进程对应的目录下查看
[root@Betty conf]# cat /proc/3756/status Name: mysql-proxy State: S (sleeping) SleepAVG: 98% Tgid: 3756 Pid: 3756 PPid: 3755 TracerPid: 0 Uid: 0 0 0 0 Gid: 0 0 0 0 FDSize: 64 Groups: 0 1 2 3 4 6 10 VmPeak: 252512 kB VmSize: 200244 kB VmLck: 0 kB VmHWM: 3752 kB VmRSS: 3752 kB VmData: 118404 kB VmStk: 88 kB VmExe: 16 kB VmLib: 10888 kB VmPTE: 288 kB StaBrk: 0df5c000 kB Brk: 0e087000 kB StaStk: 7fffb0fea000 kB Threads: 5 SigQ: 1/38784 SigPnd: 0000000000000000 ShdPnd: 0000000000000000 SigBlk: 0000000000000000 SigIgn: 0000000000381000 SigCgt: 0000000180004a03 CapInh: 0000000000000000 CapPrm: 00000000fffffeff CapEff: 00000000fffffeff Cpus_allowed: 00000000,00000000,00000000,00000000,00000000,00000000,00000000,0000ffff Mems_allowed: 00000000,00000001 [root@Betty conf]#其中
Threads: 5表示该进程下包含 5 个线程（3756 进程对应的线程 + 由其创建的工作线程）。
参考： http://smilejay.com/2012/06/linux_view_threads/