9个必须掌握的Linux性能调优命令和工具

超、凢脫俗 2023-02-19 11:22 22阅读 0赞

### 文章目录 ###

*  9个必须掌握的Linux性能调优命令和工具
 *   *  前言
     *  top命令
     *  htop命令
     *  ps命令
     *  free命令
     *  vmstat命令
     *  iosat命令
     *  netstat命令
     *  df命令
     *  du命令

# 9个必须掌握的Linux性能调优命令和工具 #

## 前言 ##

一般来说，Linux性能调优涉及CPU、内存和 IO，包括进程、线程、程序堆栈、内存、Swap、CPU调度、内存调度、网络连接和IO读写等。

本文介绍了Linux查看资源使用情况和性能调优常用的命令，包括`top`、`htop`、`ps`、`free`、`vmstat`、`iostat`、`netstat`、`df`和`du`命令。

## top命令 ##

`top`命令用来监控系统的资源使用情况，包括CPU、内存、Swap、进程和线程等。

命令：

# 运行top
    top
    
    # 显示进程的完整命令
    top -c

> 推荐使用下面的htop命令来代替top命令。

## htop命令 ##

`htop`命令用来监控系统的资源使用情况，包括CPU、内存、Swap、进程和线程等。相比`top`命令，`htop`命令更能更强大，显示也更加直观。

命令：

# 运行htop
    htop

概要信息说明：

*  CPU使用率：数字1、2、…表示CPU有几个核，后面的进度条用不同颜色来表示不同维度的CPU使用率，最后是CPU使用率；
 *  内存使用率：Mem后面的进度条用不同颜色来表示不同维度的内存使用率（绿色：used，蓝色：buffers，橙色：cache)，最后是内存使用率（used / total);
 *  Swap使用率：Swap后面的进度条显示已用的Swap，最后是Swap使用率（used / total)，如果系统关闭了Swap，则进度条为空，Swap使用率为0K/0K；
 *  进程和线程统计：Tasks：进程数，thr：线程数，running：正在运行的进程数；
 *  系统平均负载统计：Load average：前1分钟平均负载、前5分钟平均负载和前15分钟平均负载；负载越低说明CPU越空闲，负载越高说明CPU越忙：
    
     *  负载低于0.7 \* CPU核数：CPU使用率正常；（道路通畅）
     *  负载高于0.7 \* CPU核数：CPU使用率较高，需要关注；（道路堵车，需要交警到场疏导交通）
     *  负载高于1 \* CPU核数：CPU使用率过高，需要关注；（道路严重堵车，可能发生了交通事故，需要交警马上到现场处理）
     *  负载高于5 \* CPU核数：系统超负荷运转，无法正常响应；（交通瘫痪，可能道路已经被水淹无法通行，需要投入抢险力量恢复交通）
 *  系统已连续运行时间：Uptime后面为系统从上次启动后，已连续运行时间，可以倒推系统上次启动时间；

详细信息说明：

*  PID：进程ID；
 *  USER：进程所有者；
 *  PRI：进程优先级；
 *  NI：nice值，负值表示高优先级，正值表示低优先级；
 *  VIRT：进程使用的虚拟内存(virtual memory)；
 *  RES：进程使用的物理内存(physical memory)；
 *  SHR：进程使用的共享内存（shared memory);
 *  S：进程状态，R（Running）正在运行的进程、S（Sleeping）休眠的进程、T/S(Traced/Stopped) 已停止或中止的进程 或 Z（Zommbie）僵尸进程；
 *  CPU%：进程使用的CPU时间百分比；
 *  MEM%：进程使用的内存百分比；
 *  TIME+：进程已连续运行时间；
 *  Command：进程的执行命令；

常用快捷键：

*  上下箭头：上下滚动查看进程；
 *  `u`：显示指定用户的进程；
 *  `P`：按照进程使用的CPU时间百分比排序；
 *  `M`：按照进程使用的内存百分比排序；
 *  `T`：按照进程已连续运行时间排序；

参考：

*  [https://linuxtogether.org/htop-command-explanation/][https_linuxtogether.org_htop-command-explanation]
 *  [https://www.softprayog.in/tutorials/htop-command-in-linux][https_www.softprayog.in_tutorials_htop-command-in-linux]
 *  [https://scoutapm.com/blog/understanding-load-averages][https_scoutapm.com_blog_understanding-load-averages]
 *  [htop官网][htop]

## ps命令 ##

# 查看java进程
    # e(every) 所有进程
    # f(full format) 完整输出格式
    ps -ef | grep nginx
    
    # 不显示grep本身
    ps -ef | grep nginx | grep -v grep
    
    # 获取指定进程的PID
    ps -ef | grep java | grep jenkins | grep -v grep | awk '{print $2}'
    
    # 根据进程的PID中止进程
    ps -ef | grep java | grep jenkins | grep -v grep | awk '{print $2}' | xargs kill -9
    
    # 查看进程堆栈
    # p(path) 显示完整路径
    pmap <pid> -p
    
    # 查看9091端口是哪个容器进程
    docker ps | grep 9091

`ps -ef`格式：

*  UID：进程的UID（用户）
 *  PID：进程ID
 *  PPID：父进程ID
 *  C：CPU使用时间百分比
 *  STIME
 *  TTY
 *  TIME
 *  CMD：启动进程的命令

## free命令 ##

`free`命令用来查看内存和Swap的使用情况。

命令：

# 以适合阅读的形式输出(h: human)
    free -h
    
    # 以MB格式输出（m: MB)
    free -m
    
    # 合计Mem和Swap(t: total)
    free -h -t
    
    # 统计3次，每秒1次(c: count)
    free -h -c 3
    
    # 统计5次，每2秒统计1次(s: second)
    free -h -t -c 5 -s 2

说明：

*  **Total**: The amount of RAM installed in your system.
 *  **Used**: Equal to `Total`\-(`Free`\+`Buffers`\+`Cache`).
 *  **Free**: The amount of memory completely unused by anything.
 *  **Shared**: Memory taken by the `tmpfs` file systems.
 *  **Buffer**: The data structures that are maintained to provide an index for everything stored in `Cache`.
 *  **Cache**: Data read from the hard drive, modified data waiting to be written back to the hard drive, and other computed values.
 *  **Available**: What’s really free. An estimate of the memory in `Free`, `Buffer`, and `Cache` that could be used to satisfy a memory request.

简单来说，total是系统总内存，used就是系统已用内存，total - used 就是系统可用内存。

参考：

*  [https://www.howtogeek.com/456943/how-to-use-the-free-command-on-linux/][https_www.howtogeek.com_456943_how-to-use-the-free-command-on-linux]

## vmstat命令 ##

`vmstat`命令用来统计进程、内存、Swap、IO和CPU等信息。

命令：

# 运行vmstat
    vmstat
    
    # 每5秒统计1次
    vmstat 5
    
    # 每5秒统计1次，共统计4次
    vmstat 5 4
    
    # 以MB格式输出内存使用情况
    vmstat 5 4 -S M
    
    # 显示统计概要信息
    vmstat -s

说明：

Proc

*  *r*: The number of runnable processes. These are processes that have been launched and are either running or are waiting for their next time-sliced burst of CPU cycles.
 *  *b*: The number of processes in uninterruptible sleep. The process isn’t sleeping, it is performing a blocking system call, and it cannot be interrupted until it has completed its current action. Typically the process is a device driver waiting for some resource to come free. Any queued interrupts for that process are handled when the process resumes its usual activity.

Memory

*  *swpd*: the amount of virtual memory used. In other words, how much memory has been swapped out.,
 *  *free*: the amount of idle (currently unused) memory.
 *  *buff*: the amount of memory used as buffers.
 *  *cache*: the amount of memory used as cache.

Swap

*  *si*: Amount of virtual memory swapped *in* from swap space.
 *  *so*: Amount of virtual memory swapped *out* to swap space.

*  *bi*: Blocks received from a block device. The number of data blocks used to swap virtual memory back into RAM.
 *  *bo*: Blocks sent to a block device. The number of data blocks used to swap virtual memory out of RAM and into swap space.

System

*  *in*: The number of interrupts per second, including the clock.
 *  *cs*: The number of context switches per second. A context switch is when the kernel swaps from system mode processing into user mode processing.

CPU

These values are all percentages of the total CPU time.

*  *us*: Time spent running non-kernel code. That is, how much time is spent in user time processing and in nice time processing.
 *  *sy*: Time spent running kernel code.
 *  *id*: Time spent idle.
 *  *wa*: Time spent waiting for input or output.
 *  *st*: Time stolen from a virtual machine. This is the time a virtual machine has to wait for the hypervisor to finish servicing other virtual machines before it can come back and attend to this virtual machine.

参考：

*  [https://www.howtogeek.com/424334/how-to-use-the-vmstat-command-on-linux/][https_www.howtogeek.com_424334_how-to-use-the-vmstat-command-on-linux]
 *  [https://www.tecmint.com/linux-performance-monitoring-with-vmstat-and-iostat-commands/][https_www.tecmint.com_linux-performance-monitoring-with-vmstat-and-iostat-commands]

## iosat命令 ##

`iostat`命令用来统计磁盘IO和CPU等信息。

命令：

# 运行iostat
    iostat
    
    # 以MB格式输出
    iostat -m
    
    # 查看指定磁盘（分区）
    iostat -m -p vda
    
    # 每2秒统计一次，共统计3次
    iostat -m 2 3

说明：

CPU信息：

*  **%user :** It shows the percentage of CPU being utilization that while executing at the user level.
 *  **%nice :** It shows the percentage of CPU utilization that occurred while executing at the user level with a nice priority.
 *  **%system :** It shows the percentage of CPU utilization that occurred while executing at the system (kernel) level.
 *  **%iowait :** It shows the percentage of the time that the CPU or CPUs were idle during which the system had an outstanding disk I/O request.
 *  **%steal :** It shows the percentage of time being spent in involuntary wait by the virtual CPU or CPUs while the hypervisor was servicing by another virtual processor.
 *  **%idle :** It shows the percentage of time that the CPU or CPUs were idle and the system did not have an outstanding disk I/O request.

磁盘信息：

*  **Device :** The device/partition name is listed in */dev* directory.
 *  **tps :** The number of transfers per second that were issued to the device. Higher tps means the processor is busier.
 *  **Blk\_read/s :** It shows the amount of data read from the device expressed in a number of blocks (kilobytes, megabytes) per second.
 *  **Blk\_wrtn/s :** The amount of data written to the device expressed in a number of blocks (kilobytes, megabytes) per second.
 *  **Blk\_read :** It shows the total number of blocks read.
 *  **Blk\_wrtn :** It shows the total number of blocks written.

参考：

*  [https://www.geeksforgeeks.org/iostat-command-in-linux-with-examples/][https_www.geeksforgeeks.org_iostat-command-in-linux-with-examples]
 *  [https://www.techrepublic.com/article/how-to-use-the-linux-iostat-command-to-check-on-your-storage-subsystem/][https_www.techrepublic.com_article_how-to-use-the-linux-iostat-command-to-check-on-your-storage-subsystem]

## netstat命令 ##

`netstat`命令用来统计网络连接和端口等信息。

命令：

# 显示在侦听的TCP/UDP网络连接，包括程序和端口信息
    # u(UDP)
    # t(TCP)
    # n(port)
    # l(listen)
    # p(program)
    netstat -utnlp
    
    # 只显示在侦听的TCP网络连接，包括程序和端口信息
    netstat -tnlp
    
    # 查看某个端口被哪个进程使用
    # a(all)
    netstat -anp | grep 6379
    
    # 查看某个进程在哪个端口
    netstat -anp | grep redis
    
    # 查看docker启动的进程在哪个端口
    docker ps | grep jenkins

## df命令 ##

`df`命令用来统计磁盘使用情况。

命令：

# 查看全部文件系统的磁盘使用情况
    df -h
    
    # 查看指定目录所在的文件系统的磁盘使用情况
    df -h ~
    
    # 不显示docker文件系统
    df -h | grep -v docker

## du命令 ##

`du`命令用来统计指定目录的大小。

命令：

# 统计某个目录大小
    du -sh ~
    
    # 统计目录下各个子目录和文件的大小
    du -h ~
    
    # 统计目录下各个子目录和文件的大小，并显示合计大小
    du -ch ~
    
    # 只统计下一级目录大小
    du -h --max-depth 1
    
    # 只统计下一级目录大小，单位为MB，从大到小排序
    du -m --max-depth 1 | sort -rn
    
    # 只统计下一级目录大小，单位为MB，从大到小排序，返回最大的10个文件（目录）
    du -m --max-depth 1 | sort -rn | head -11

[https_linuxtogether.org_htop-command-explanation]: https://linuxtogether.org/htop-command-explanation/
[https_www.softprayog.in_tutorials_htop-command-in-linux]: https://www.softprayog.in/tutorials/htop-command-in-linux
[https_scoutapm.com_blog_understanding-load-averages]: https://scoutapm.com/blog/understanding-load-averages
[htop]: http://hisham.hm/htop/index.php
[https_www.howtogeek.com_456943_how-to-use-the-free-command-on-linux]: https://www.howtogeek.com/456943/how-to-use-the-free-command-on-linux/
[https_www.howtogeek.com_424334_how-to-use-the-vmstat-command-on-linux]: https://www.howtogeek.com/424334/how-to-use-the-vmstat-command-on-linux/
[https_www.tecmint.com_linux-performance-monitoring-with-vmstat-and-iostat-commands]: https://www.tecmint.com/linux-performance-monitoring-with-vmstat-and-iostat-commands/
[https_www.geeksforgeeks.org_iostat-command-in-linux-with-examples]: https://www.geeksforgeeks.org/iostat-command-in-linux-with-examples/
[https_www.techrepublic.com_article_how-to-use-the-linux-iostat-command-to-check-on-your-storage-subsystem]: https://www.techrepublic.com/article/how-to-use-the-linux-iostat-command-to-check-on-your-storage-subsystem/