设置linux系统cpu固定频率，报如下错误：
bash
$ sudo cpufreq-set -c 0 -f 1000MHz
Error setting new values. Common errors:
- Do you have proper administration rights? (super-user?)
- Is the governor you requested available and modprobed?
- Trying to set an invalid policy?
- Trying to set a specific frequency, but userspace governor is not available,
for example because of hardware which cannot be set to a specific frequency
or because the userspace governor isn't loaded?从Ubuntu使用intel某些cpu的pc上默认使用intel_pstate cpufreq driver。后果就是只有performance和powersave两个governor可用。可通过下面命令确认：
bash
$ cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
driver: intel_pstate
CPUs which run at the same hardware frequency: 0
CPUs which need to have their frequency coordinated by software: 0
maximum transition latency: 4294.55 ms.
hardware limits: 800 MHz - 3.90 GHZ
available cpufreq governors: performance, powersave
current policy: frequency should be within 800 MHz and 3.90 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 800 MHz.
analyzing CPU 1:
driver: intel_pstate
CPUs which run at the same hardware frequency: 1
CPUs which need to have their frequency coordinated by software: 1
maximum transition latency: 4294.55 ms.
hardware limits: 800 MHz - 3.90 GHZ
available cpufreq governors: performance, powersave
current policy: frequency should be within 800 MHz and 3.90 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 802 MHz.可以看到
driver: intel_pstate
available cpufreq governors: performance, powersave
禁用intel_pstate:
修改 /etc/default/grub中GRUB_CMDLINE_LINUX_DEFAULT内容
原始内容： GRUB_CMDLINE_LINUX_DEFAULT="quietsplash"
更改后的内容：GRUB_CMDLINE_LINUX_DEFAULT="quietsplash intel_pstate=disable"
更新grub ：sudo update-grub
重启机器
设置cpu固定频率
sudo cpufreq-set -g userspace
sudo cpupower cpufreq-set -f 2G
查看cpu频率
cat /proc/cpuinfo | grep MH