Linux TOP Command Parameters [reprinted]

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