One-shot-oriented event timers management
mav at FreeBSD.org
Mon Aug 30 10:21:26 UTC 2010
Gary Jennejohn wrote:
> On Mon, 30 Aug 2010 13:07:38 +0300
> Alexander Motin <mav at FreeBSD.org> wrote:
>> Gary Jennejohn wrote:
>>> Ah, I think I see it now. My desktop has only C1 enabled. Is that it?
>>> Unfortunately, it appears that only C1 is supported :(
>> Yes, as I have said, at this moment empty ticks skipped only while CPU
>> is in C2/C3 states. In C1 state there is no way to handle lost events on
>> wake up. While it may be not very dangerous, it is not very good.
> Too bad. I'd say that systems which are limited to C1 don't benefit
> much (or not at all) from your changes.
For this moment - indeed not much. As I have said, feature with skipping
ticks is on early development stage. I've just implemented it in most
straightforward way, abusing feature provided by ACPI. To benefit other
systems and platforms, more tight integration with interrupt, callout
and possibly scheduler subsystem will be needed.
More information about the freebsd-hackers