On 08/27/2013 12:23 PM, Viresh Kumar wrote: > Hi Guys, > > I was trying to run following on my thinkpad: > > watch -n1 cat /sys/devices/system/cpu/cpu*/cpuidle/state*/usage > > I can see lots of activities on State 1-4, but not much on state 0.. > I thought we should enter this state as soon as we come out to > non-idle state.. And so this count must be changing quite rapidly. > > Is this a bug?
Hi Viresh, the menu governor tries always to stick to C1 (state1) as default state, look at the menu_select function. The state0 (not C0 but 'poll') will happen when the next timer event is less than 5us, this occurs rarely. You can easily spot it by doing while $(true); usleep 2; done The poll state is x86 specific where the cpu detects the 'rep nop' instructions to do some power saving. Hope that helps -- Daniel -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
