Linux Process Management

Process Management

Process Processes

A process opened by an application

PIDProcess ID

Type:

User space Process

Kernel space Process

To view the status of a process statically

# PS

[[Email protected] ~]# PS>>>> View the process of this terminal

PID TTY Time CMD

4206 pts/0 00:00:00 Bash

4378 pts/0 00:00:00 PS

How to use options:

BSD style: Option without horizontal- PS aux

SYSV style: Option required with horizontal line -ps-elf

BSD Style:

A shows the process associated with the terminal

U Show the user who started the process

x Show processes unrelated to the terminal

[Email protected] ~]# PS a

PID TTY STAT Time COMMAND

3303 Tty2 ss+ 0:00/sbin/mingetty/dev/tty2

3305 Tty3 ss+ 0:00/sbin/mingetty/dev/tty3

[[Email protected] ~]# PS u

USER PID%cpu%MEM VSZ RSS TTY STAT START time COMMAND

Root 3303 0.0 0.0 4064 544 tty2 ss+ 09:06 0:00/sbin/mingetty/dev/tty2

Root 3305 0.0 0.0 4064 544 tty3 ss+ 09:06 0:00/sbin/mingetty/dev/tty3

User running the process

Percentage of CPU consumed by the%CPU process

Percentage of MEM defeated by the%MEM process

VSZ Virtual memory set, process-exclusive memory + share exists

The unique memory of the RSS process

Status of the STAT process

D: Non-disruptive sleep (wait for disk IO to complete)

S: interruptible sleep (no need to wait for disk IO to complete)

R: Run or ready

T: Stop

Z: Zombie Zombie

<: high-priority process

will be executed by CPU first

Will get more CPU execution time

N: Low-priority process

+: Processes in the foreground process group

L: Multithreaded process (thread)

S: Session process first process, one connection parent process

[[Email protected] ~]# PS aux | Less

USER PID%cpu%MEM VSZ RSS TTY STAT START time COMMAND

Root 1 0.0 0.0 19364 1536? Ss 09:05 0:00/sbin/init

Root 2 0.0 0.0 0 0? S 09:05 0:00 [Kthreadd]

Root 3 0.0 0.0 0 0? S 09:05 0:00 [migration/0]

Root 4 0.0 0.0 0 0? S 09:05 0:00 [ksoftirqd/0]

With square brackets for system (Linux kernel boot)

Incompetence Allende brackets (user process)

[[Email protected] ~]# PS aux | grep vim

Root 5550 0.2 0.0 143972 3760 pts/2 s+ 10:25 0:00 vim/etc/fstab

Root 5564 0.0 0.0 103260 860 pts/0 s+ 10:25 0:00 grep--color vim

SYSV style options:

- e Show All Processes

- L Detailed information

- F display in long format (more field content)

[Email protected] ~]# Ps-elf | Less

F S UID PID PPID C PRI NI ADDR SZ wchan stime TTY time CMD

4 S root 1 0 0 0-4841 poll_s 09:05? 00:00:00/sbin/init

1 S root 2 0 0 0-0 kthrea 09:05? 00:00:00 [Kthreadd]

1 S Root 3 2 0-40--0 migrat 09:05? 00:00:00 [migration/0]

1 S Root 4 2 0 0-0 ksofti 09:05? 00:00:00 [ksoftirqd/0]

1 S Root 5 2 0-40--0 cpu_st 09:05? 00:00:00 [stopper/0]

5 S Root 6 2 0-40--0 watchd 09:05? 00:00:00 [watchdog/0]

1 S Root 7 2 0-40--0 migrat 09:05? 00:00:00 [MIGRATION/1]

Process priority:

0----139

The smaller the data, the higher the first level

High-priority processes:

Get CPU More Execution time

will be executed by CPU first

Nice value:

New priority = Old Priority +nice value

-20----19

Ordinary users can only adjust the nice value, that is, to reduce the process priority

Root user is free to adjust the nice value

Show Process Tree

[Email protected] ~]# Pstree

Init─┬─abrtd

├─acpid

├─atd

├─AUDITD───{AUDITD}

├─automount───4*[{automount}]

├─bonobo-activati───{bonobo-activat}

├─certmonger

├─clock-applet

├─CONSOLE-KIT-DAE───63*[{CONSOLE-KIT-DA}]

├─crond

Show Process PID

[Email protected] ~]# pidof vim

5696

[Email protected] ~]#

Dynamically view the status of a process

# Top

top-10:53:46 up 1:48, 3 users, Load average:0.12, 0.19, 0.16

tasks:239 Total, 2 running, 237 sleeping, 0 stopped, 0 zombie

Cpu (s): 7.6%us, 1.6%sy, 0.0%ni, 90.6%id, 0.0%wa, 0.0%hi, 0.2%si, 0.0%st

mem:16084568k Total, 2529012k used, 13555556k free, 70044k buffers

swap:8388604k Total, 0k used, 8388604k free, 626388k cached

7.6%us CPU consumed by user processes

1.6%sy CPU consumed by the system process

0.0%ni CPU adjusted by priority process

90.6%idCPU Idle

0.0%wa CPU consumed by the process waiting for disk IO

CPU (s): Show all CPU averages, press 1 to show the usage of each CPU

Top Interactive Instructions:

M: Sort by memory usage

P: Sort by CPU usage

T: Sort by run time

L: Whether to display top line 1th information

M: Whether memory usage information is displayed

T: whether to display CPU and task information

C: Whether the full command line is displayed

Q: Exit Top

Displays CPU usage at the current moment

[Email protected] ~]# uptime

11:00:25 up 1:54, 3 users, load average:0.39, 0.26, 0.19

Top options:

-D 1: Specify how often top information is refreshed

-B: Show process information in batch mode

-N 2: Display of two batches of information

# top-d 1-b-N 2

To view server performance:

1, PS, top

2, Df-ht

3, Free-m

[Email protected] ~]# uptime

11:39:00 up 3:24, 4 users, Load average:0.00, 0.01, 0.05

# mpstat View CPU

# Vmstat View Memory

# iostat View disk

[Email protected] ~]# Rpm-qf/usr/bin/iostat

Sysstat-10.1.5-7.el7.x86_64

[Email protected] ~]#

Process Control

Signal: Signal

View all signals

[Email protected] ~]# kill-l

1) SIGHUP 2) SIGINT 3) sigquit 4) Sigill 5) SIGTRAP

6) SIGABRT 7) Sigbus 8) SIGFPE 9) SIGKILL) SIGUSR1

One) (SIGSEGV) (SIGUSR2) sigpipe) sigalrm) SIGTERM

Sigstkflt) (SIGCHLD) sigcontSIGSTOP) SIGTSTP

(Sigttin) Sigttou() Sigurg) sigxcpu) Sigxfsz

(Sigvtalrm) sigprof) sigwinchSIGIO) SIGPWR

Sigsys) (sigrtmin) sigrtmin+1) sigrtmin+2Notoginseng) sigrtmin+3

Sigrtmin+4) sigrtmin+5(sigrtmin+6) sigrtmin+7) sigrtmin+8

Sigrtmin+9) (sigrtmin+10) sigrtmin+11() sigrtmin+12) sigrtmin+13

(sigrtmin+14) sigrtmin+15() SIGRTMAX-14) SIGRTMAX-13) SIGRTMAX-12

SIGRTMAX-11) SIGRTMAX-10SIGRTMAX-9) SIGRTMAX-857) SIGRTMAX-7

(SIGRTMAX-6) (SIGRTMAX-5) SIGRTMAX-4) SIGRTMAX-3) SIGRTMAX-2

SIGRTMAX-1) Sigrtmax

Common signals:

1 SIGHUP: Let a process not restart, you can reread its configuration file, and let the new configuration take effect

2 SIGINT: Hardware interrupt signal, CTRL + C

9 SIGKILL: Kill a process

SIGTERM: Terminating a process

How do I call a signal?

Signal Number: kill-9 <PID>

Signal Name: Kill-sigkill <PID>

Signal name shorthand: Kill-kill <PID>

# Kill <PID>

# Killall <PROCESS_NAME>

Control how the process runs (foreground/background)

Front desk: Occupy command prompt

1) control commands run in the background

# Command &

[email protected] ~]# Firefox &

2) Viewing applications in the background

[Email protected] ~]# jobs-l

[1]+ 12066 Running Firefox &

3) put the running instructions in the background and pause the operation

CTRL + Z

4) Back up the backstage program to the foreground to continue running

# FG < background task number >

[[email protected] ~]# FG 1

This article is from the "lyw666" blog, make sure to keep this source http://lyw666.blog.51cto.com/12823216/1957484

Linux Process Management