http://acpi.sourceforge.net/documentation/processor.html
# cat /proc/acpi/processor/CPU/power
active state: C0
max_cstate: C8
bus master activity: 00000000
maximum allowed latency: 2000000000 usec
states:
C1: type[C1] promotion[--] demotion[--] latency[001] usage[00000000] duration[00000000000000000000]
C2: type[C2] promotion[--] demotion[--] latency[001] usage[1913406120] duration[00000004986133384038]
C3: type[C3] promotion[--] demotion[--] latency[085] usage[18967922] duration[00000000025276809103]
めも
http://www.t12.jp/~ryuta/rwiki/
echo -n 1:3:0 > /proc/acpi/processor/CPU0/power $ echo -n 3:0:1 > /proc/acpi/processor/CPU0/power. とかやるとC2を使わないようになります．
未検証
