linux下关闭服务器的CPU（睿频）自动降频

因为在负载低的时候，CPU工作在较低的频率，为了节能，但在服务器突发访问时，CPU不断在高低频率上切换，所以需要关闭自动降频。

root@cache:~# grep -E '^model name|^cpu MHz' /proc/cpuinfo
model name	: Intel(R) Xeon(R) CPU E3-1220 V2 @ 3.10GHz
cpu MHz		: 3101.000
model name	: Intel(R) Xeon(R) CPU E3-1220 V2 @ 3.10GHz
cpu MHz		: 1600.000
model name	: Intel(R) Xeon(R) CPU E3-1220 V2 @ 3.10GHz
cpu MHz		: 3101.000
model name	: Intel(R) Xeon(R) CPU E3-1220 V2 @ 3.10GHz
cpu MHz		: 1600.000
root@cache:~# for CPUFREQ in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do [ -f $CPUFREQ ] || continue; echo -n performance > $CPUFREQ; done
root@cache:~# grep -E '^model name|^cpu MHz' /proc/cpuinfo
model name	: Intel(R) Xeon(R) CPU E3-1220 V2 @ 3.10GHz
cpu MHz		: 3101.000
model name	: Intel(R) Xeon(R) CPU E3-1220 V2 @ 3.10GHz
cpu MHz		: 3101.000
model name	: Intel(R) Xeon(R) CPU E3-1220 V2 @ 3.10GHz
cpu MHz		: 3101.000
model name	: Intel(R) Xeon(R) CPU E3-1220 V2 @ 3.10GHz
cpu MHz		: 3101.000

# service cpuspeed stop

1:

# lsmod | grep ondemand
cpufreq_ondemand        8764  0 
freq_table              3751  2 cpufreq_ondemand,acpi_cpufreq
# rmmod cpufreq_ondemand acpi_cpufreq freq_table