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Fedora Linux CPU Frequency Scaling using cpupower
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- Name
- ttyS3
命令行方式1 -- 不依赖外部工具
查看当前生效的 scaling_governor
cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
查看可用的 scaling_governor
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
设置为高性能模式
对于台式机来说，我觉得没有什么理由不设置为 performance 模式
echo performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
设置为节能模式
echo powersave | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
查看其它信息：
❯ /bin/ls -1 /sys/devices/system/cpu/cpu0/cpufreq/
affected_cpus
base_frequency
cpuinfo_max_freq
cpuinfo_min_freq
cpuinfo_transition_latency
energy_performance_available_preferences
energy_performance_preference
related_cpus
scaling_available_governors
scaling_cur_freq
scaling_driver
scaling_governor
scaling_max_freq
scaling_min_freq
scaling_setspeed
比如查看当前频率我们读取 scaling_cur_freq 这个文件即可:
watch cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq
Scaling governors 的具体含义
Scaling governors are power schemes determining the desired frequency for the CPU. Some request a constant frequency, while others implement algorithms to dynamically adjust according to the system load. The governors included in the kernel are:
Note: Each governor is compatible with any scaling driver, except for
intel_pstateandamd_pstatein active mode. These provide pseudo-governors in the form ofpowersaveandperformance. See Autonomous frequency scaling.
| Governor | Description |
|---|---|
| performance | Run the CPU at the maximum frequency, obtained from /sys/devices/system/cpu/cpuX/cpufreq/scaling_max_freq. |
| powersave | Run the CPU at the minimum frequency, obtained from /sys/devices/system/cpu/cpuX/cpufreq/scaling_min_freq. |
| userspace | Run the CPU at user-specified frequencies, configurable via /sys/devices/system/cpu/cpuX/cpufreq/scaling_setspeed. |
| ondemand | Scales the frequency dynamically according to current load. Jumps to the highest frequency and then possibly backs off as the idle time increases. |
| conservative | Scales the frequency dynamically according to current load. It does so more gradually than ondemand. |
| schedutil | Scheduler-driven CPU frequency selection source, source. |
命令行方式2 -- cpupower
cpupower 命令在 Fedora 里面由 kernel-tools 包提供，如果没有你需要安装一下：
sudo dnf install -y kernel-tools
查看当前状态:
sudo cpupower frequency-info
直接设置 CPU 工作在特定频率:
cpupower frequency-set -f clock_freq
设置 为 performance 模式
cpupower frequency-set -g performance
目前 Fedora 不再提供 cpupower.service 了， 这里从 Arch 抄一个：
[Unit]
Description=Apply cpupower configuration
ConditionVirtualization=!container
[Service]
Type=oneshot
EnvironmentFile=/etc/default/cpupower
ExecStart=/usr/bin/cpupower $CPUPOWER_ARGS
RemainAfterExit=yes
[Install]
WantedBy=multi-user.target
/etc/default/cpupower 内容如下：
CPUPOWER_ARGS="frequency-set -g performance"
sudo systemctl enable --now cpupower
sudo systemctl status cpupower
sudo cpupower frequency-info
命令行方式3 -- powerprofilesctl
powerprofilesctl 命令由 power-profiles-daemon 包提供。
https://gitlab.freedesktop.org/upower/power-profiles-daemon/-/blob/main/README.md
https://fedoraproject.org/wiki/Changes/Power_Profiles_Daemon
它主要是通过 DBus 与 power-profiles-daemon.service 起来的 power-profiles-daemon 进程通信.
❯ powerprofilesctl
* performance:
CpuDriver: intel_pstate
Degraded: no
balanced:
CpuDriver: intel_pstate
PlatformDriver: placeholder
power-saver:
CpuDriver: intel_pstate
PlatformDriver: placeholder
❯ powerprofilesctl get
performance
misc
kernel-tools 里的其它命令
kernel-tools 这个包里除了cpupower 命令， 还有一些其它实用工具：
❯ rpm -qlv kernel-tools | rg /usr/bin
-rwxr-xr-x 1 root root 14696 Mar 6 08:00 /usr/bin/centrino-decode
-rwxr-xr-x 1 root root 78592 Mar 6 08:00 /usr/bin/cpupower
-rwxr-xr-x 1 root root 18792 Mar 6 08:00 /usr/bin/gpio-event-mon
-rwxr-xr-x 1 root root 14696 Mar 6 08:00 /usr/bin/gpio-hammer
-rwxr-xr-x 1 root root 14696 Mar 6 08:00 /usr/bin/gpio-watch
-rwxr-xr-x 1 root root 31096 Mar 6 08:00 /usr/bin/iio_event_monitor
-rwxr-xr-x 1 root root 35192 Mar 6 08:00 /usr/bin/iio_generic_buffer
-rwxr-xr-x 1 root root 123792 Mar 6 08:00 /usr/bin/intel-speed-select
-rwxr-xr-x 1 root root 64461 Mar 6 08:00 /usr/bin/kvm_stat
-rwxr-xr-x 1 root root 14880 Mar 6 08:00 /usr/bin/lsgpio
-rwxr-xr-x 1 root root 22904 Mar 6 08:00 /usr/bin/lsiio
-rwxr-xr-x 1 root root 26984 Mar 6 08:00 /usr/bin/page_owner_sort
-rwxr-xr-x 1 root root 14704 Mar 6 08:00 /usr/bin/powernow-k8-decode
-rwxr-xr-x 1 root root 44224 Mar 6 08:00 /usr/bin/slabinfo
-rwxr-xr-x 1 root root 43736 Mar 6 08:00 /usr/bin/tmon
-rwxr-xr-x 1 root root 132920 Mar 6 08:00 /usr/bin/turbostat
-rwxr-xr-x 1 root root 39896 Mar 6 08:00 /usr/bin/x86_energy_perf_policy
Fedora 这个包里并没有包含 cpupower.service
不过它带了一个 /usr/lib/systemd/system/kvm_stat.service
Service that logs KVM kernel module trace events
/usr/bin/kvm_stat -dtcz -s 10 -L /var/log/kvm_stat.csv
看上去是把 kvm 内核模块的状态信息输出到 csv 文件。 并且还带了相应的 logrotate 配置文件 /etc/logrotate.d/kvm_stat
intel_pstate
The newer kernel version is using the intel_pstate as the default driver. which is only supported governor performance and powersave.
In order to use the governor ondemand, you need to disable the intel_pstate driver and using the acpi-cpufreq driver as default.
Edit the grub configuration.
sudo nvim /etc/default/grub
Add the following configuration.
GRUB_CMDLINE_LINUX_DEFAULT="intel_pstate=disable"
Regenerate your grub.
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
Now the intel_pstate driver will be disabled, and the acpi_cpufreq will be enabled by default.
内核文档： https://docs.kernel.org/admin-guide/pm/intel_pstate.html
intel_pstateis not modular, so it cannot be unloaded, which means that the only way to pass early-configuration-time parameters to it is via the kernel command line. However, its configuration can be adjusted via sysfs to a great extent. In some configurations it even is possible to unregister it via sysfs which allows another CPUFreq scaling driver to be loaded and registered (see below).
不过，我应该大概率用不到 ondemand 模式。
refs
How to make a CPU governor change permanent?
How-to Increasing performance by changing CPU governor and reducing swappiness