【原创】如何查看某进程下运行的线程-白红宇

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）。