svn commit: r208494 - in head/sys: amd64/amd64 amd64/include i386/i386 i386/include kern pc98/cbus sys x86/isa x86/x86

[Andriy Gapon]

on 24/05/2010 19:06 Alexander Motin said the following:
> Andriy Gapon wrote:
>> on 24/05/2010 14:40 Alexander Motin said the following:
>>> Author: mav
>>> Date: Mon May 24 11:40:49 2010
>>> New Revision: 208494
>>> URL: http://svn.freebsd.org/changeset/base/208494
>>>
>>> Log:
>>>   - Implement MI helper functions, dividing one or two timer interrupts with
>>>   arbitrary frequencies into hardclock(), statclock() and profclock() calls.
>>>   Same code with minor variations duplicated several times over the tree for
>>>   different timer drivers and architectures.
>>>   - Switch all x86 archs to new functions, simplifying the code and removing
>>>   extra logic from timer drivers. Other archs are also welcome.
>> could you please describe the new code/KPI in greater detail, perhaps on a more
>> appropriate mailing list?
> 
> Sent some summary to arch at .

Thanks!

>> For me it is not immediately obvious why IPI_PROFCLOCK is gone now.  I haven't
>> spent much time reverse engineering this change and perhaps it's easier for you
>> to describe the change.
> 
> IPI_PROFCLOCK is not used any more. Separation between statclock() and
> profclock() now handled in common machine-independent code. Timer driver
> generates interrupts, MD code manages timers configuration and events
> redistribution to every CPU, using up to two IPIs if needed, MI code do
> the rest of things.

Thank you for the explanation.
BTW, with e.g. HPET we may consider using a separate clock for profiling, but I
am not sure.

-- 
Andriy Gapon