Question regarding broadcast timer/cpuidle and /proc/interrupts

[Daniel Lezcano <daniel.lezcano@linaro.org>]

Hi All,

I have a question regarding the behavior of cpuidle on pandaboard.

1. cpuidle is enabled

2. The deep idle states seem to be reach

for i in $(find /sys/devices/system/cpu -name "usage"); do echo "$i :
$(cat $i)"; done
/sys/devices/system/cpu/cpu0/cpuidle/state0/usage : 7049
/sys/devices/system/cpu/cpu0/cpuidle/state1/usage : 17
/sys/devices/system/cpu/cpu0/cpuidle/state2/usage : 1341
/sys/devices/system/cpu/cpu1/cpuidle/state0/usage : 6318
/sys/devices/system/cpu/cpu1/cpuidle/state1/usage : 17
/sys/devices/system/cpu/cpu1/cpuidle/state2/usage : 1341

3. Regarding the cpuidle driver code : the "state1" and "state2" are
coupled states where the broadcast timer is used instead of the local
timer. I assume this is because they go down when we reach these idle
states.

4. The content of /proc/interrupts shows no broadcast timer used at all.

...
IPI1:          0          0  Timer broadcast interrupts
...

Shouldn't be the broadcast timer used sometimes ? or did I miss something ?

Thanks.

  -- Daniel


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