Re: x86_64 and AMD with C1E

["Mikhail Kshevetskiy" <mikhail.kshevetskiy@gmail.com>]

2007/10/19, Chuck Ebbert <cebbert@redhat.com>:
> On 10/01/2007 02:15 AM, Mikhail Kshevetskiy wrote:
> > Hello,
> >
> > I have ASUS F3T notebook with dualcore AMD processor. It has c1e feature
> > enabled. I test linux-2.6.23-rc8-hrt1 kernel. Everything is work (thanks
> > to lapic disable patch), but i have to many processor interrupts per
> > seconds (about 260 additional timer interrupts).
> >
> > The same situation can be observed for linux-2.6.22. Moreover the same
> > problem exist with i386 kernel (test with 2.6.21, 2.6.22, 2.6.22-hrt6,
> > 2.6.23-rc5-hrt1).
> >
> > The problem disappear when I disable c1e on both cores. In this case
> > lapic is not disabled. The back side of this patch is the disabling of
> > all C-state including C1. As result the power consumption increase from
> > 23 (c1e enabled) to 27 (c1e disabled) watts.
> >
> > I fill something wrong here.
> > Is it possible to reduce the amount of timer interrupts?
> > Is it possible to force enable C1,C2 and C3 states when c1e disabled?
> >
>
> How are you disabling C1E?
>
>
dirty hack, i just follow the FreeBSD way and clear C1e bit in lapic
initialization code. I make it for test purpose only, so i do not produce a
patch.

Mikhail