cpupower調整CPU主頻

1、調節策略

performance：將CPU頻率固定工作在其支持的最高運行頻率上，不動態調節，可以獲取到最大的性能。

powersave: 將 CPU 頻率設置為最低的所謂 “省電” 模式，CPU 會固定工作在其支持的最低運行頻率上。

因此這兩種 governors 都屬於靜態 governor，即在使用它們時 CPU 的運行頻率不會根據系統運行時負載的變化動態作出調整。

這兩種 governors 對應的是兩種極端的應用場景，使用 performance governor 是對系統高性能的最大追求，而使用 powersave governor 則是對系統低功耗的最大追求。

userspace：最早的 cpufreq 子系統通過 userspace governor 為用戶提供了這種靈活性。

系統將變頻策略的決策權交給了用戶態應用程序，並提供了相應的接口供用戶態應用程序調節 CPU 運行頻率使用。

ondemand：按需快速動態調整 CPU 頻率， 一有 cpu 計算量的任務，就會立即達到最大頻率運行，等執行完畢就立即回到最低頻率；

ondemand：userspace 是內核態的檢測，用戶態調整，效率低。

conservative: 與 ondemand 不同，平滑地調整 CPU 頻率，頻率的升降是漸變式的, 會自動在頻率上下限調整，和 ondemand 的區別在於它會按需分配頻率，而不是一味追求最高頻率；

2、查看當前cpu可用的策略

[root@CENTOS ~]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
conservative userspace powersave ondemand performance
[root@CENTOS ~]#

查看cpu0可用的策略：cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors

3、查看當前cpu生效的策略

[root@CENTOS ~]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
conservative
[root@CENTOS ~]#

查看cpu0當前的策略：cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

4、查看當前CPU頻率

[root@CENTOS ~]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
1000000
[root@CENTOS ~]#

5、查看當前所有CPU的信息

[root@CENTOS ~]# cpupower -c all frequency-info
analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 10.0 us
  hardware limits: 1000 MHz - 1.90 GHz
  available frequency steps:  1.90 GHz, 1.90 GHz, 1.80 GHz, 1.70 GHz, 1.60 GHz, 1.50 GHz, 1.40 GHz, 1.30 GHz, 1.20 GHz, 1.10 GHz, 1000 MHz
  available cpufreq governors: conservative userspace powersave ondemand performance
  current policy: frequency should be within 1000 MHz and 1.90 GHz.
                  The governor "conservative" may decide which speed to use
                  within this range.
  current CPU frequency: 1000 MHz (asserted by call to hardware)
  boost state support:
    Supported: yes
    Active: yes

6、設置所有CPU的模式

設置所有CPU為性能模式
[root@CENTOS57 ~]# cpupower -c all frequency-set -g performance
Setting cpu: 0
Setting cpu: 1
Setting cpu: 2
Setting cpu: 3
Setting cpu: 4
Setting cpu: 5
Setting cpu: 6
Setting cpu: 7
Setting cpu: 8
Setting cpu: 9
Setting cpu: 10
Setting cpu: 11
Setting cpu: 12
Setting cpu: 13
Setting cpu: 14
Setting cpu: 15

cpupower -c all frequency-set -g powersave
cpupower -c all frequency-set -g "conservative"

7、查看某個CPU的信息

[root@CENTOS57 ~]# cpupower -c 1 frequency-info
analyzing CPU 1:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 1
  CPUs which need to have their frequency coordinated by software: 1
  maximum transition latency: 10.0 us
  hardware limits: 1000 MHz - 1.90 GHz
  available frequency steps:  1.90 GHz, 1.90 GHz, 1.80 GHz, 1.70 GHz, 1.60 GHz, 1.50 GHz, 1.40 GHz, 1.30 GHz, 1.20 GHz, 1.10 GHz, 1000 MHz
  available cpufreq governors: conservative userspace powersave ondemand performance
  current policy: frequency should be within 1000 MHz and 1.90 GHz.
                  The governor "performance" may decide which speed to use
                  within this range.
  current CPU frequency: 1.90 GHz (asserted by call to hardware)
  boost state support:
    Supported: yes
    Active: yes

cpupower -c 0 frequency-info        #查看CPU0的信息
cpupower -c 1 frequency-info        #查看CPU1的信息
cpupower -c 2 frequency-info        #查看CPU2的信息

8、查看CPU的頻率

[root@CENTOS57 ~]# cat /proc/cpuinfo | grep "cpu MHz*"
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000
cpu MHz         : 1901.000

參考引用：https://baijiahao.baidu.com/s?id=1644209827783392362&wfr=spider&for=pc