top命令

• top命令是最常用的查看Linux系统信息的命令之一，可以实时显示系统中各个进程的资源占用情况。

top - 02:55:09 up 15 days,  5:35,  1 user,  load average: 0.00, 0.02, 0.05
Tasks:  65 total,   1 running,  64 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0.3 us,  0.3 sy,  0.0 ni, 99.3 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem(主存) :  1016164 total,    87432 free,   505544 used,   423188 buff/cache
KiB Swap(交换分区):        0 total,        0 free,        0 used.   356124 avail Mem 
  PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND                                                                                                                                            
 1197 root      10 -10  126536   7940   5196 S  0.3  0.8  74:49.37 AliYunDun                                                                                                                                          
 1382 root      20   0   65376   2664   2224 S  0.3  0.3   3:33.74 aliyun-service                                                                                                                                     
    1 root      20   0   43268   3080   1864 S  0.0  0.3   1:27.90 systemd                                                                                                                                            
    2 root      20   0       0      0      0 S  0.0  0.0   0:00.06 kthreadd                                                                                                                                           
    3 root      20   0       0      0      0 S  0.0  0.0   0:02.81 ksoftirqd/0                                                                                                                                        
    5 root       0 -20       0      0      0 S  0.0  0.0   0:00.00 kworker/0:0H                                                                                                                                       
    7 root      rt   0       0      0      0 S  0.0  0.0   0:00.00 migration/0                                                                                                                                        
    8 root      20   0       0      0      0 S  0.0  0.0   0:00.00 rcu_bh                                                                                                                                             
    9 root      20   0       0      0      0 S  0.0  0.0   1:12.31 rcu_sched                                                                                                                                          
   10 root      rt   0       0      0      0 S  0.0  0.0   0:07.27 watchdog/0                                                                                                                                         
   12 root      20   0       0      0      0 S  0.0  0.0   0:00.00 kdevtmpfs                                                                                                                                          
   13 root       0 -20       0      0      0 S  0.0  0.0   0:00.00 netns                                                                                                                                              
   14 root      20   0       0      0      0 S  0.0  0.0   0:00.45 khungtaskd                                                                                                                                         
   15 root       0 -20       0      0      0 S  0.0  0.0   0:00.00 writeback                                                                                                                                          
   16 root       0 -20       0      0      0 S  0.0  0.0   0:00.00 kintegrityd                                                                                                                                        
   17 root       0 -20       0      0      0 S  0.0  0.0   0:00.00 bioset                                                                                                                                             
   18 root       0 -20       0      0      0 S  0.0  0.0   0:00.00 kblockd                                                                                                                                            
   19 root       0 -20       0      0      0 S  0.0  0.0   0:00.00 md                                                                                                                                                 

* PID     = Process Id            进程的ID
* USER    = Effective User Name   进程所有者的用户名
* PR      = Priority              进程优先级
* NI      = Nice Value            进程的nice值
* VIRT    = Virtual Image (KiB)   进程使用的虚拟内存总量，单位是KB
* RES     = Resident Size (KiB)   进程使用的并且未被换出的物理内存大小，单位是KB
* SHR     = Shared Memory (KiB)   共享内存大小，单位是KB
* S       = Process Status        进程的状态。(D=不可中断的睡眠状态，R=运行，S=睡眠，T=跟踪/停止，z=僵尸进程)
* %CPU    = CPU Usage             上一次更新到现在的CPU时间占用百分比         
* %MEM    = Memory Usage (RES)    进程使用物理内存的百分比
* TIME+   = CPU Time, hundredths  进程使用的CPU时间总计，单位是10ms
* COMMAND = Command Name/Line     命令名或命令行
  PPID    = Parent Process pid  
  UID     = Effective User Id   
  RUID    = Real User Id        
  RUSER   = Real User Name      
  SUID    = Saved User Id       
  SUSER   = Saved User Name     
  GID     = Group Id            
  GROUP   = Group Name          
  PGRP    = Process Group Id    
  TTY     = Controlling Tty     
  TPGID   = Tty Process Grp Id  
  SID     = Session Id          
  nTH     = Number of Threads   
  P       = Last Used Cpu (SMP) 
  TIME    = CPU Time            
  SWAP    = Swapped Size (KiB)  
  CODE    = Code Size (KiB)     
  DATA    = Data+Stack (KiB)    
  nMaj    = Major Page Faults   
  nMin    = Minor Page Faults   
  nDRT    = Dirty Pages Count   
  WCHAN   = Sleeping in Function
  Flags   = Task Flags 
  CGROUPS = Control Groups      
  SUPGIDS = Supp Groups IDs     
  SUPGRPS = Supp Groups Names   
  TGID    = Thread Group Id     
  ENVIRON = Environment vars    
  vMj     = Major Faults delta  
  vMn     = Minor Faults delta  
  USED    = Res+Swap Size (KiB) 
  nsIPC   = IPC namespace Inode 
  nsMNT   = MNT namespace Inode 
  nsNET   = NET namespace Inode 
  nsPID   = PID namespace Inode 
  nsUSER  = USER namespace Inode
  nsUTS   = UTS namespace Inode