[Linux] CPUコアの有効化/無効化

gistfile1.md

制御の仕方

カーネル起動時のパラメータ( maxcpus=number_of_core )で指定

SMPでも起動時はシングルコアにする (起動が早くなる?)

$ cat grub.cfg
linux /vmlinuz-3.13-1-amd64 root=/dev/mapper/vg-lv ro quiet elevator=noop maxcpus=1

sysfs

# echo 1 > /sys/devices/system/cpu/cpu1/online

起動したらマルチコアに戻す

$ cat /etc/rc.local
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.
for i in /sys/devices/system/cpu/cpu*/online; do
    echo 1 > "$i"
done

exit 0