Event timers

[Alexander Motin]

John Baldwin wrote:
> On Monday 24 May 2010 11:57:39 am Alexander Motin wrote:
>> You should agree that event timers code we have now (hardclock,
>> statclock and profclock source) is real mess. The code is completely
>> machine-dependent, many times duplicated (I have found 4 or 5 equal
>> implementations and many more trivial ones), very tangled and
>> inflexible. While it is acceptable for some platforms with single
>> interrupt source running on hz, x86 with it's many different timers
>> definitely doesn't look good. So I've decided to clean it.
>>
>> 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).
> 
> Have you looked at the dynamic ticks patches on hackers@?  Those already 
> include changes for 5), although he currently only has support for LAPIC and 
> is working on adding HPET support.

Yes, I've seen it. But without complete timer stuff rewrite it seems
hopeless to me. That is one more reason why I want to do it.

-- 
Alexander Motin