Process Management 1. Process Management

Process Management 1. Process Management
 

Process Management:1.1 view Processes

1.2 Process Management

1. process description ◆ a process is a program or command being executed. Every process is a running entity and has its own address space and occupies certain system resources.

 

2. Role of process management ◆ determine the server health status

◆ View all processes in the system

◆ Killing Processes

3. View All PROCESSES IN THE SYSTEM

[Root @ localhost ~] # Ps aux

# View all processes in the system and use the BSD operating system format

[Root @ localhost ~] # Ps-le

# View all processes in the system and use the standard Linux Command Format

[Xiaofeng @ localhost ~] $ Ps aux

User pid % CPU % MEM VSZ RSS TTY STAT START TIME COMMAND

Root 1 3.4 0.6 128092 6692? Ss/usr/lib/syste

Root 2 0.0 0.0 0 0? S [kthreadd]

Root 3 0.0 0.0 0 0? S [ksoftirqd/0]

Root 4 0.0 0.0 0 0? S [kworker/]

Root 5 0.0 0.0 0 0? S <[kworker/0: 0 H]

Root 6 0.0 0.0 0 0? S [kworker/u256:

USER: the USER who generates the process;

PID: ID of the process

% CPU: the percentage of cpu resources occupied by the process. The higher the CPU usage, the more resources the process consumes;

% MEM: Percentage of physical memory occupied by the process. The higher the memory occupied, the more resources the process consumes;

VSZ: the virtual memory occupied by the process, in KB;

RSS: the actual physical memory occupied by the process, in KB;

TTY: the terminal on which the process runs. The tty1-tty7 represents the local console terminal, the tty1-tty6 is the local character terminal, tty is the graphics terminal. Pts/0-255 represents a virtual terminal.

STAT: Process status. Common statuses include: R: Run, S: Sleep, T: Stop, s: contains sub-processes, and +: Located in the background

START: the START time of the process.

TIME: the computing TIME that the process occupies the cpu. Note that it is not the system TIME.

COMMAND: name of the COMMAND that generates this process

 

 

4. view the System Health Status

[Root @ localhost ~] # Top [Options]

Option:

-D seconds: specifies the number of seconds that the top command updates. By default, commands that can be executed in the top command interaction mode in 3 seconds are as follows:

? Or h: displays the help of the interactive mode.

P: sort by cpu usage. This option is used by default.

M: sort by memory usage

N: sort by PID

Q: Exit top.

[Xiaofeng @ localhost ~] $ Top

Top-15:47:59 up 41 min, 2 users, load average: 0.00, 0.01, 0.05

Task: 114 total, 1 running, 113 sleeping, 0 stopped, 0 zombie

% Cpu (s): 0.3 us, 0.0 sy, 0.0 ni, 99.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st

KiB Mem: 999964 total, 594100 free, 154968 used, 250896 buff/cache

KiB Swap: 524284 total, 524284 free, 0 used. 657584 avail Mem

Pid user pr ni virt res shr s % CPU % mem time + COMMAND

541 root 20 0 302772 6276 S 4820 0.7. 33 vmtoolsd

720 root 20 0 178808 4468 S 3596 0.3. 62 vmtoolsd

2942 xiaofeng 20 0 157676 2140 R 1508 0.3 0: 00. 18 top

1 root 20 0 128092 6696 S 3948 0.0. 97 systemd

2 root 20 0 0 0 S 0.0 0.0. 00 kthreadd

3 root 20 0 0 0 S 0.0 0.0. 01 ksoftirqd +

This is the first line of information, which is the task queue information.

 

Top-12:26:46 up 1 day, 2 users, load average: 0.00, 0.01, 0.05

Content	Description
12:26:46	Current System Time
Up 1 day, 13: 32	System running time. The local machine has been running for 1 day, 13 hours, 32 minutes.
2 users	Currently, two users are logged on.
Load average: 0.00, 0.01, 0.05	The average load of the system in the previous 1 minute, 5 minutes, and 15 minutes. Generally, when the value is less than 1, the load is small. If the value is greater than 1, the system has exceeded the load.

 

Second-Action Process Information

Task: 114 total, 1 running, 113 sleeping, 0 stopped, 0 zombie

 

Content	Description
Tasks: 114 total	Total number of processes in the system
1 running	Number of Running Processes
113 sleeping	Sleep Process
0 stopped	Stopping Process
0 zombie	Botnets. If it is not 0, manually check the zombie Process

 

 

Third behavior cpu Information

% Cpu (s): 0.3 us, 0.0 sy, 0.0 ni, 99.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st

Content	Description
% Cpu (s): 0.3 us	Cpu usage in user mode
0.0 sy	Cpu usage in System Mode
0.0 ni	Cpu usage of user processes that have changed their priorities
99.7 id	Percentage of idle cpu
0.0 wa	Cpu usage percentage of processes waiting for Input/Output
0.0 hi	Percentage of cpu occupied by the hard interrupt request service
0.0 si	Percentage of cpu used by the soft interrupt request service
0.0 st	St (Steal time) virtual time percentage. That is, the percentage of time the virtual cpu waits for the actual cpu when there is a virtual machine

 

Fourth behavior physical memory information

KiB Mem: 999964 total, 594100 free, 154968 used, 250896 buff/cache

Content	Description
Mem: 999964 total	Total physical memory, in KB
594100 free	The number of idle physical memory. We use virtual machines. In total, only MB of memory is allocated, so we have MB of idle memory.
154968 used	Number of physical memory used
250896 buff/cache	Buffer memory size

 

Fifth behavior swap partition (swap) Information

KiB Swap: 524284 total, 524284 free, 0 used. 657584 avail Mem

Content	Description
Swap: 524284 total	Total size of swap partition (Virtual Memory)
524284 free	Size of idle swap Partition
0 used	Swap partition size used
657584 avail	Size of available swap partitions

 

TopThe command itself is a good system resource. Don't open it all the time, so pay special attention to this!

 

5. view the process tree

[Root @ localhost ~] # Pstree [Option]

Option:

-P: displays the pid of the process.

-U: displays the user of the process.