查看系统所有的CPU

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blueline:/sys/devices/system/cpu $ ls
core_ctl_isolated cpu2 cpu5 cpufreq               hang_detect_gold   isolated   offline  power
cpu0              cpu3 cpu6 cpuidle               hang_detect_silver kernel_max online   present
cpu1              cpu4 cpu7 gladiator_hang_detect hotplug            modalias   possible uevent
blueline:/sys/devices/system/cpu $ cat possible
0-7

查看所有正在运行的核

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blueline:/sys/devices/system/cpu $ cat online
0-7
blueline:/sys/devices/system/cpu $

查看所有的未在运行的核

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blueline:/sys/devices/system/cpu $ cat online
0-7
blueline:/sys/devices/system/cpu $ cat offline

blueline:/sys/devices/system/cpu $

查看CPU0所有的相关信息

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blueline:/sys/devices/system/cpu $ cd cpu0/
blueline:/sys/devices/system/cpu/cpu0 $ ls
cache    cpufreq hotplug of_node power rq-stats         subsystem uevent
core_ctl cpuidle isolate online  regs  sched_load_boost topology
blueline:/sys/devices/system/cpu/cpu0 $

查看CPU0是否正在运行状态

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blueline:/sys/devices/system/cpu/cpu0 $ cat online
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blueline:/sys/devices/system/cpu/cpu0 $

我们可以0写入到当前CPU0的online文件中，这个CPU的核就关闭了。

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blueline:/sys/devices/system/cpu/cpu0 $ echo 0 > online
/system/bin/sh: can't create online: Permission denied
1|blueline:/sys/devices/system/cpu/cpu0 $ remount
/system/bin/sh: remount: not found
127|blueline:/sys/devices/system/cpu/cpu0 $ su
blueline:/sys/devices/system/cpu/cpu0 # echo 0 > online
blueline:/sys/devices/system/cpu/cpu0 # cat online
0
blueline:/sys/devices/system/cpu/cpu0 #

这个时候我们在回到外面一层文件里面的onlin文件和offline文件。我们可以看到对应的核已经关闭掉

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blueline:/sys/devices/system/cpu # cat online
1-7
blueline:/sys/devices/system/cpu # cat offline
0
blueline:/sys/devices/system/cpu #

这个时候我们再去看看当前正在运行的核心