ubuntu系统笔记本电池坏掉的情况下，性能严重下降的解决办法

1. 问题描述

   • 开机出现以下问题

     the ac power adapter type cannot be determined

   • 开机选择diagnose进行检查发现

     the battery is reaching the end of its life

     显示电池已经到达生命尽头

2. 问题原因分析
   电池坏掉后cpu动不动就跑满了，因为此时cpu的工作模式被修改了

   • 安装cpufrequency工具

     sudo apt-get install cpufrequtils 

   • 查看cpu信息

     cpufreq-info

     
     所有内核都变成了powersave的模式

3. 修改模式

   sudo cpufreq-set -c 0 -g performance
   sudo cpufreq-set -c 1 -g performance
   sudo cpufreq-set -c 2 -g performance
   sudo cpufreq-set -c 3 -g performance
   
   modprobe msr
   wrmsr 0x1FC 2 //关闭BD PROCHOT
   
   watch -n 1 "cat /proc/cpuinfo | grep MHz"

4. 再次查看 cpufreq-info ，此时模式已经修改过来，电脑不再卡顿

5. systemctl stop ondemand
   systemctl disable ondemand
   
   vim /etc/sysfs.conf
   devices/system/cpu/cpu0/cpufreq/scaling_governor = performance
   devices/system/cpu/cpu1/cpufreq/scaling_governor = performance
   devices/system/cpu/cpu2/cpufreq/scaling_governor = performance
   devices/system/cpu/cpu3/cpufreq/scaling_governor = performance
   reboot