Re: [PATCH] Use local APIC timer to drive kernel clocks

On Fri, 14 Jan 2005 15:46:31 -0500, John Baldwin <jhb_at_freebsd.org> wrote:
> I have a patch that uses the local APIC timer to drive the kernel clocks
> (hardclock, statclock, and profclock) instead of the ISA timer and RTC.  The
> advantage of this change is that SMP machines can stop using IPIs to bounce
> clock interrupts around all the time.  Currently the code will always use the
> local APIC timer if an APIC is being used, but it might be desirable to only
> use the timer if we have more than one CPU.  Some caveats and details:
> 
(...)
> 
> Please test and let me know if there are any regressions.  Thanks.  Patch is
> at http://www.FreeBSD.org/~jhb/patches/lapic_timer.patch

Yes! My SMP system had a big problem with the clock (it did 500Hz when
it should do 1000Hz, 50Hz when it should do 100Hz, etc...) that caused
all kinds of weird problems and miscalculations. This patch fixes it!

Thanks,

Arjan

> 
> --
> John Baldwin <jhb_at_FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
> "Power Users Use the Power to Serve"  =  http://www.FreeBSD.org
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