Event timers

Alexander Motin mav at FreeBSD.org
Thu May 27 03:02:42 UTC 2010


Brandon Gooch wrote:
> 2010/5/26 Alexander Motin <mav at freebsd.org>:
>> Alexander Motin wrote:
>>> Andriy Gapon wrote:
>>>> on 24/05/2010 18:57 Alexander Motin said the following:
>>>>> I have defined several points on that way:
>>>>> 1*. clean low-level timer drivers from unrelated stuff,
>>>>> 2*. make some common code machine-independent,
>>>>> 3. write common driver API for event timers (alike to one we have now
>>>>> for time counters) to make adding more drivers possible,
>>>>> 4. add support for HPET as event timer in addition to time counter,
>>>>> 5. add support for timers in one-shot mode (LAPIC and HPET).
>>>> I wonder how much you have progressed for 3,4,5.
>>> Not really much yet. Learned existing code and hardware specs, have some
>>> thought and ready to proceed.
>> Here is first approach to 3:
>> http://people.freebsd.org/~mav/et.20100526.patch
>> , - created common API, heavily refactored attimer, atrtc and lapic
>> drivers, written simple and formal common code. Now it is possible to
>> use any one or two of these three drivers for either hardclock or
>> statclock by just changing weights or disabling them. Tested on i386,
>> should work on amd64, probably broken on XEN and pc98 for now.
> 
> From my (minimal) understanding of the timer issues in FreeBSD,
> restructuring in this area requires a bold, fearless developer:
> 
> Thanks for taking this on Alexander!
> 
> Are these proposed patches made available for user testing, or mainly
> for developer review purposes?

Now mostly for developers review. It is not finished yet. Most of
features interesting for users is still ahead.

-- 
Alexander Motin


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