Linux TOP Command Parameters [reprinted]

Source: Internet
Author: User

Tool for real-time monitoring or viewing system resource usage-TOP

The top command is a common performance analysis tool in Linux. It can display the resource usage of various processes in the system in real time, similar to the Windows Task Manager.

The following describes how to use it:

(Real-time monitoring system resource usage diagram)

 

The first five lines in the statistical information area are the overall statistical information of the system:

The first line is the task queue information, which is the same as the execution result of the uptime command. The content is as follows:

01:06:48 Current Time
Up :22 System running time, in the format of minutes
1 user Current Login User count
Load average: 0.06, 0.60, 0.48 System load, that is, the average length of the task queue.
The three values are the average values from 1 minute, 5 minutes, and 15 minutes ago to the present.


2. 3. Information about the process and CPU. When multiple CPUs exist, the content may exceed two lines. The content is as follows:

Tasks: 29 total Process count
1 running Number of Running Processes
28 sleeping Number of sleep Processes
0 stopped Number of stopped Processes
0 zombie Number of zombie Processes
Cpu (s): 0.3% us CPU usage percentage of user space
1.0% sy CPU usage of kernel space
0.0% ni CPU usage percentage of processes that have changed their priorities in the process space
98.7% id Idle CPU percentage
0.0% wa Percentage of CPU time waiting for Input and Output
0.0% hi Total time consumed by CPU service during hard interruption
0.0% si, 0.0% st Total CPU service Time spent on Soft Interrupt, Steal Time


The memory information of the last two behaviors is as follows:

Mem: 191272 k total Total physical memory
173656 k used Total physical memory used
17616 k free Total idle memory
22052 k buffers Memory Used as kernel Cache
Swap: 192772 k total Total number of swap Areas
0 k used Total number of swap zones used
192772 k free Total number of idle swap Areas
123988 k cached The total number of buffer swap areas.
The content in the memory is swapped out to the swap zone and then into the memory, but the used swap zone has not been overwritten,
This value indicates the size of the SWAp zone where the content already exists.
When the corresponding memory is swapped out again, you do not have to write data to the swap zone.


Detailed information about each process is displayed at the bottom of the process information area.

First, let's get to know the meaning of each column:

Serial number Column name Description
1 PID Process id
2 PPID Parent process id
3 RUSER Real user name
4 UID User ID of the process owner
5 USER User Name of the process owner
6 GROUP Group Name of the process owner
7 TTY The terminal name of the startup process. If the process is not started from the terminal, it is displayed?
8 PR Priority
9 NI Nice value. negative value indicates high priority, positive value indicates low priority
10 P The last CPU used is only meaningful in multiple CPU environments.
11 % CPU CPU usage from the last update to the present
12 TIME Total CPU time used by the process, in seconds
13 TIME + Total CPU time used by the process, in 1/100 seconds
14 % MEM Percentage of physical memory used by the Process
15 VIRT Total virtual memory used by the process, in kb, VIRT = SWAP + RES
16 SWAP The swap size in the virtual memory used by the process, in kb.
17 RES Physical memory used by the process, not swapped out, in kb, RES = CODE + DATA
18 CODE Physical memory occupied by executable code, in kb
19 DATA Physical memory occupied by parts other than executable code (Data Segment + stack), in kb
20 SHR Size of shared memory, in kb
21 NFLT Page error count
22 MCM t The number of pages that have been modified since the last write to the present.
23 S Process status:
D= Uninterrupted sleep
R= Run
S= Sleep
T= Trail/stop
Z= Zombie Process
24 COMMAND Command name/command line
25 WCHAN If the process is sleeping, the system function name displayed in sleep
26 Flags Task flag, refer to sched. h


By default, only important PID, USER, PR, NI, VIRT, RES, SHR, S, % CPU, % MEM, TIME +, and COMMAND columns are displayed!

You can use the following shortcut keys to change the display content:
Change the display content throughFYou can select the displayed content (press f to display the list of columns, press a-z to display or hide the corresponding columns, and press enter to confirm)
PressOThe key can change the Column Display order (a-z in lower case can move the corresponding column to the right, while the upper-case A-Z can move the corresponding column to the left, and finally press the Enter key to confirm)
In upper caseFOrOKey, and then press a-z to sort the process according to the corresponding columns, and the upper caseRThe key can reverse the current sorting.

 

Reference:

Linux top commands
Http://bbs.linuxtone.org/forum.php? Mod = viewthread & tid = 1684 & fromuid = 34304

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