Linux top command each parameter detailed "reprint"

Tools for real-time monitoring or viewing system resource usage--top

The top command is a common performance analysis tool under Linux that shows the resource usage of individual processes in the system in real time, similar to the Task Manager for Windows.

Here is a detailed description of how it is used:

(Real-time Monitoring system Resource Usage graph)

The first five elements of the statistical information area are the statistical information of the whole system:

The first line is the task queue information, with the execution result of the uptime command. The contents are as follows:

01:06:48	Current time
Up 1:22	System run time, format last: minutes
1 user	Number of currently logged on users
Load average:0.06, 0.60, 0.48	System load, which is the average length of the task queue. The three values were 1 minutes, 5 minutes, and 15 minutes ago to the present average.

Second to third behavior process and CPU information, when there are multiple CPUs, these contents may exceed two lines. The content is as follows:

tasks:29 Total	Total number of processes
1 Running	Number of processes that are running
Sleeping	Number of processes for sleep
0 stopped	Number of processes stopped
0 Zombie	Number of zombie processes
Cpu (s): 0.3% US	Percentage of CPU occupied by user space
1.0% Sy	Percentage of CPU consumed by kernel space
0.0% ni	CPU percentage of processes that have changed priority in user process space
98.7% ID	Percentage of idle CPU
0.0% WA	Percentage of CPU time waiting for input and output
0.0% hi	The total amount of time that the CPU spends on hard interrupts
0.0% Si, 0.0%st	The amount of time the CPU spends on soft interrupts, steal

Last two behavior memory information. The contents are as follows:

MEM:191272K Total	Total Physical Memory
173656k used	Total amount of physical memory used
17616k Free	Total Free Memory
22052k buffers	Amount of memory to use as the kernel cache
SWAP:192772K Total	Total Swap Area
0k used	Total number of swap areas used
192772k Free	Total Free Swap Area
123988k Cached	The total amount of buffer swap area. The in-memory content is swapped out to the swap area and then swapped in to memory, but the used swap area has not been overwritten. This value is the size of the swap area where the content already exists in memory. When the corresponding memory is swapped out again, it is no longer necessary to write to the swap area.

The details of each process are shown below the process information area statistics area.

Let's start by understanding the meaning of the columns:

Serial number	Column Name	Meaning
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 Process owner
7	Tty	The terminal name of the startup process. A process that is not started from the terminal is displayed as?
8	PR	Priority level
9	NI	Nice value. Negative values indicate high priority, positive number indicates low priority
10	P	Last CPU used, only meaningful in multi-CPU environment
11	%cpu	CPU time consumption percentage last updated to current
12	Time	Total CPU time used by the process, in seconds
13	time+	Total CPU time used by the process, Unit 1/100 sec
14	%MEM	Percentage of physical memory used by the process
15	VIRT	Total amount of virtual memory used by the process, Unit kb,virt=swap+res
16	SWAP	The size, in kilobytes, of the virtual memory that the process is using, swapped out.
17	Res	The amount of physical memory not swapped out by the process, Unit Kb,res=code+data
18	CODE	The amount of physical memory the executable code occupies, in kilobytes
19	DATA	The amount of physical memory that is used by parts other than executable code (data segment + stack), in kilobytes
20	Shr	Shared memory size, in kilobytes
21st	Nflt	Number of page faults
22	Ndrt	The number of pages that were modified the last time it was written to.
23	S	Process Status: D= non-interruptible sleep state R= run S= Sleep T= trace/Stop Z= Zombie Process
24	COMMAND	Command name/command line
25	Wchan	If the process is sleeping, the system function name in sleep is displayed
26	Flags	Task Flag, reference sched.h

Only the more important PID, USER, PR, NI, VIRT, RES, SHR, S,%cpu,%MEM, time+, and COMMAND columns are displayed by default!

You can change the display by using the following shortcut keys:
Change the display by the F key to select what to display (press the F key to display a list of columns, press A-Z to show or hide the corresponding column, and then press ENTER to confirm)
Press the o key to change the order in which the columns are displayed (A-Z in lowercase can move the corresponding column to the right, while the uppercase A-Z can move the corresponding column to the left, and then press ENTER to determine)
Press the uppercase F or O key, and then press A-Z to sort the process by the appropriate column, while the uppercase R key reverses the current sort.

Article reference:

The Linux top command is detailed
http://bbs.linuxtone.org/forum.php?mod=viewthread&tid=1684&fromuid=34304