Madhavan Venkataraman wrote:
> On 09/01/09 17:31, Garrett D'Amore wrote:
>> Joerg Schilling wrote:
>>> Jerry Gilliam <jerry.gilliam at sun.com> wrote:
>>>
>>>
>>>> 2. Project Summary
>>>> 2.1. Project Description:
>>>> The tickless project aims at implementing the services
>>>> provided by the
>>>> clock cyclic in an event driven fashion. The first
>>>> sub-project is the
>>>> decoupling of the lbolt and lbolt64 variables from clock().
>>>> These two
>>>> variables are incremented at each firing of the clock
>>>> cyclic and provide
>>>> a time reference to the system. They are being replaced by
>>>> two routines
>>>> that are backed by gethrtime(), the existing
>>>> ddi_get_lbolt() and
>>>> the new ddi_get_lbolt64(), introduced as a migration path
>>>> for existing
>>>> non-DDI compliant consumers.
>>>>
>>>
>>> If this results in being able to sleep with less than 10 ms
>>> granularity without
>>> setting a high-res tick, you get many + from me!
>>>
>>
>> Actually, I could really use the ability to use a timer based service
>> that had a smaller window than 10 msec. For example, many audio
>> devices have crummy interrupt capabilities... its a lot nicer
>> (smoother audio) if I have a reliable way to get a periodic running
>> at smaller intervals. (5 to 10 msec, but with precision -- the
>> current stuff is simply too coarse.)
>>
>> This would simplify a lot of audio device drivers. And make them
>> more robust as well. :-)
>>
>> - Garrett
>>
> The callout subsystem has been redesigned to support small and high
> resolution
> timers. The condition variable module has also been enhanced to make
> use of the
> high resolution timers. (see functions that end with _hires in
> condvar.c). However,
> this is not exported via DDI. If some consolidation private driver
> wants to cheat
> and use these interfaces (ugh), it can. But if you feel there is a
> real need, someone
> should work to export the hires CV interfaces to DDI. What I am saying
> is that
> the functionality is there. It just needs to be exported.
Can I use fine grained timers with ddi_periodic()? Or is it still only
tick granularity?
- Garrett
>
> Of course, it is outside the scope of what Rafael is doing. Someone
> else has to
> bell the cat.
>
> Madhavan
