Li, Aubrey wrote: > Bill.Holler at Sun.COM wrote: > > >> Li, Aubrey wrote: >> >>> Bill Holler wrote: >>> >>> >>> >>>>>> You can probably take it from another CPU that's not in deep-c >>>>>> state (if there is one?) >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> Yes. Our initial thoughts are to sync up with a running CPU >>>>> via cross call. We need to run performance experiments with >>>>> different implementations to see what the costs are. >>>>> >>>>> >>>>> >>>> Synching TSC/APIC with a running cpu is potentially much more >>>> accurate than using the HPET. However this will induce drift. >>>> >>>> >>>> >>> if all the cpus are in the deeper c-state,...? >>> >>> >> An external source such as the HPET or platform pm timer needs to >> be used if all cpus are in deeper c-state. :-) >> >> > > Are you working on the ACPI timer driver as well? >
Yes. Do you have an estimate for how many systems have an ACPI timer but do not have an HPET timer? Bill > Thanks, > -Aubrey >
