Eric Saxe wrote:
> Bill Holler wrote:
>
>> The ACPI PM timer interface looks very simple. :-)
>>
>> hwtimer.c indicates the ACPI PM timer is either 24 or 32-bits.
>> Comments indicate 24-bit timers roll-over in about 4.66 seconds
>> and 32-bit timers roll-over in about 19.88 minutes.
>>
HPET timers can be 32-bit. I have only see 64-bit HPET timers,
so I am not sure if 32-bit timers are at all common.
>> That will be an upper bounds on how long a cpu can be idle
>> if this timer is used for measuring the idle time.
>> If we do a good job with the power aware dispatcher and
>> callout/cyclic work, possible cpu idle time will be un-bounded
>> at least on some cpus. ;-)
>>
>>
> That would be nice. :)
>
> -Eric
>
Here are two other cases to consider:
1. offline processors.
2. Solaris disables the local APIC's timer when there are no cyclics
on this processor.
Since neither of these cases use the local APIC's timer, they do not
require lAPIC timer re-programming in idle wakeup?
Solaris should use the deepest c-state available for offline
processors. :-)
Bill
