自動 CPU 調頻節能控制
Ubuntu 10.04 以後的系統可以安裝 powernowd，(開機會自動執行 deamon)
週期的監控 CPU 使用率，可以設定上限值與下限，依據設定的 policy 自動調降/調升 CPU 頻率。
Ubuntu Linux 10.04 設定檔 ( /etc/default/powernowd )
man powernowd for details.
手動CPU 調頻控制
測試：
Lenovo Notebook X200, CPU (Pentium M) 支援四種頻率 ( 2401, 2400, 1600, 800 MHz)
CPU: Intel(R) Core(TM)2 Duo CPU P8600 @ 2.40GHz
OS: Ubuntu 10.04 TLS (Linux kernel: 2.6.32-26-generic SMP)
Script code:
#!/bin/bash
# Lenovo x200 support: 800 MHz, 1600 MHz, 2400 MHz and 2401 MHz
# 可參考 /sys/devices/system/cpu/cpu$cpu/cpufreq/scaling_available_frequencies
num=$#
if [ $num -lt 2 ]; then
echo "$0 cpu_id cpu_freq"
exit 1;
fi
cpu="$1"
cpufreq="$2""000"
echo "Set CPU$cpu with $2 MHz"
# 可參考 /sys/devices/system/cpu/cpu$cpu/cpufreq/scaling_available_governors
echo "userspace" > /sys/devices/system/cpu/cpu$cpu/cpufreq/scaling_governor
# 設定 CPU 頻率下限
echo "800000" > /sys/devices/system/cpu/cpu$cpu/cpufreq/scaling_min_freq
# 設定 CPU 頻率上限
echo "2401000" > /sys/devices/system/cpu/cpu$cpu/cpufreq/scaling_max_freq
# 設定 CPU 頻率
echo "$cpufreq" > /sys/devices/system/cpu/cpu$cpu/cpufreq/scaling_setspeed
# 確認設定
echo "cat /sys/devices/system/cpu/cpu$cpu/cpufreq/scaling_setspeed"
out=`cat /sys/devices/system/cpu/cpu$cpu/cpufreq/scaling_setspeed`
echo $out
cat /proc/cpuinfo |grep "cpu MHz"
exit 0;
使用方式：
1. 將上述 script 存為 set_cpu.sh
2. 變更權限：chmod +x set_cpu.sh
3. ./set_cpu.sh cpu_id cpu_freq ( 將 cpu_id 改成 /proc/cpuinfo 對應的 processor id, cpufreq 改成要設定的頻率, ex. ./set_cpu.sh 0 800 )
註：如果要手動調整頻率，需要移除下列自動調頻的工具
$ sudo apt-get remove powernowd cpudyn cpufreqd powersaved speedfreqd
一些資訊：
driver: acpi-cpufreq
/sys/devices/system/cpu/cpu0/cpufreq
/sys/devices/system/cpu/cpufreq/ondemand (decides the speed to use)
cpufreq-info 可以獲得 cpufreq stats (有統計每個頻率使用的百分比)
/proc/acpi 可以調整亮度, 查詢 battery 資訊
set ex. echo "70" > /proc/acpi/video/VID/LCD0/brightness
/proc/acpi/ac_adapter/AC (可查詢是否插電)
/proc/acpi/ibm 可控制 ibm devices
2.6.26 (mp)
/sys/devices/system/cpu/cpu? 中,
設定開啟、關閉 CPU: online { 1, 0 }
/sys/devices/system/cpu/sched_smt_power_savings
0 - No power saving load balance (default value)
1 - Fill one thread/core/package first for long running threads
2 - Also bias task wakeups to semi-idle cpu package for power savings
/sys/devices/system/cpu/kernel_max
kernel_max: the maximum cpu index allowed by the kernel configuration.
offline: cpus that are not online because they have been HOTPLUGGED off
or exceed the limit of cpus allowed by the kernel configuration
(kernel_max above).
online: cpus that are online and being scheduled.
possible: cpus that have been allocated resources and can be
brought online if they are present.
present: cpus that have been identified as being present in the system.
需要更多資訊可直接查看 Reference 所列資料。
Reference: (我所查看的程式碼版本是 Linux kernel source 2.6.32, 2.6.36)
Documentation/cputopology.txt for more information.
Documentation/cpuidle/.
Documentation/ABI/testing/sysfs-devices-system-cpu.
http://www.pantz.org/software/cpufreq/usingcpufreqonlinux.html
Last modified 1yr ago