Hi all, I have pushed some changes to enable idle wait's mwait C-state hint auto tuning. It will allow you enter much deeper C-state, even when ACPI does not map its deepest C-state to the deepest cpu specific C-state (mwait hint). e.g. on my laptop, w/o power cable, ACPI C3 is mapped to cpu specific C4 sub-state 0, while the deepest supported cpu specific C-state is C4 sub-state 1; w/ power cable, there is no ACPI C3 at all and ACPI C2 is mapped to cpu specific C3 sub-state 0.
You could set following tunable to enable the auto tuning: sysctl machdep.mwait.cpu_idle_hlt=1 sysctl machdep.mwait.CX.idle=AUTODEEP You could check how much time cpu specific C-states are entered by: sysctl machdep.mwait.C[0-7].entered Best Regards, sephe -- Tomorrow Will Never Die
