svn commit: r191766 - in head/sys: amd64/include amd64/isa i386/bios i386/include i386/isa i386/xen isa pc98/cbus

[John Baldwin]

On Sunday 03 May 2009 1:47:21 pm Alexander Motin wrote:
> Author: mav
> Date: Sun May  3 17:47:21 2009
> New Revision: 191766
> URL: http://svn.freebsd.org/changeset/base/191766
> 
> Log:
>   Rename statclock_disable variable to atrtcclock_disable that it actually 
is,
>   and hide it inside of atrtc driver. Add new tunable hint.atrtc.0.clock
>   controlling it. Setting it to 0 disables using RTC clock as stat-/
>   profclock sources.
>   
>   Teach i386 and amd64 SMP platforms to emulate stat-/profclocks using i8254
>   hardclock, when LAPIC and RTC clocks are disabled.
>   
>   This allows to reduce global interrupt rate of idle system down to about
>   100 interrupts per core, permitting C3 and deeper C-states provide maximum
>   CPU power efficiency.

Note that IRQ0 is not going to work for many systems with the local APIC since 
I removed the mixed-mode handling from the x86 interrupt code.

-- 
John Baldwin