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What is the meaning of each value item of linux's top command? in view of this question, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

VIRT:virtual memory usage virtual memory

1. The amount of virtual memory needed by the process, including libraries, code, data, etc.

2. If the process requests 100m of memory, but only 10m is actually used, it will grow by 100m instead of the actual usage

RES:resident memory usage resident memory

1. The amount of memory currently used by the process, excluding swap out

2. Include sharing of other processes

3. If you apply for 100m of memory and actually use 10m, it will only grow by 10m, which is opposite to VIRT

4. With regard to the memory occupied by the library, it only counts the memory occupied by the loaded library files.

SHR:shared memory shared memory

1. In addition to the shared memory of its own processes, it also includes the shared memory of other processes

2. Although the process only uses a few functions of the shared library, it contains the size of the entire shared library

3. Calculate the amount of physical memory occupied by a process: RES-SHR

4. After swap out, it will come down

DATA

1. Memory occupied by data. If top is not displayed, press the f key to display it.

2. The real data space required by the program is really to be used in operation.

During the operation of top, the display mode of the process can be controlled by the internal commands of top. The internal commands are as follows:

S-change the screen update frequency

L-turns off or turns on the representation of top information on the first line of the first part

T-turn off or turn on the representation of the first part, the second line Tasks and the third line Cpus information

M-turns off or turns on the presentation of the first part, line 4 Mem and line 5 Swap information

N-represents the list of processes in order of PID size

P-sorts the list of processes in the order of CPU occupancy

M-sorts the list of processes in order of memory footprint

H-Show help

N-sets the number of processes displayed in the process list

Q-exit top

S-change the screen update cycle

Serial number column name meaning

A PID process id

B PPID parent process id

C RUSER Real user name

D user id of the UID process owner

E user name of the owner of the USER process

F Group name of the owner of the GROUP process

G TTY the terminal name of the startup process. Processes that are not started from the terminal are displayed as?

H PR priority

I NI nice value. Negative values indicate high priority, while positive values indicate low priority.

The last CPU used by j P makes sense only in a multi-CPU environment

K% percentage of CPU time occupied from the last update of CPU to the present

Total CPU time used by TIME processes (in seconds)

Total CPU time used by the m TIME+ process (in 100s)

Percentage of physical memory used by n% MEM processes

O the total amount of virtual memory used by the VIRT process, in kb. VIRT=SWAP+RES

The size of the virtual memory used by the p SWAP process, in kb.

The amount of unswapped physical memory used by the Q RES process, in kb. RES=CODE+DATA

R the amount of physical memory occupied by CODE executable code, in kb

The amount of physical memory occupied by parts other than the executable code of s DATA (data segment + stack), in kb

T SHR shared memory size (in kb)

Number of page errors in u nFLT

V nDRT the number of pages that have been modified since it was last written.

W / S process status. (d = uninterruptible sleep state, R = running, S = sleep, T = tracking / stopping, Z = zombie process)

X COMMAND command name / command line

Y WCHAN displays the name of the system function in sleep if the process is sleeping

Z Flags task flag, refer to sched.h

By default, only the more important PID, USER, PR, NI, VIRT, RES, SHR, S,% CPU,% MEM, TIME+, COMMAND columns are displayed. You can change the display through the keyboard shortcuts below.

The f key allows you to select what is displayed. Press the f key to display the list of columns, press amurz to show or hide the corresponding columns, and finally press enter to determine.

Press o to change the order in which the columns are displayed. Press lowercase Amurz to move the corresponding column to the right, and uppercase Amurz to move the corresponding column to the left. Finally, press the enter key to confirm.

Press the uppercase F or O key, and then press amurz to sort the processes by the corresponding columns. The uppercase R key reverses the current sort.

This is the answer to the question about what the meaning of each value item of linux's top command is shared here. I hope the above content can be of some help to you. If you still have a lot of doubts to be solved, you can follow the industry information channel for more related knowledge.

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