Re: [PATCH] Option to disable AMD C1E (allows dynticks to work)

Eduard-Gabriel Munteanu
2007-12-14T10:45:21Z

On Fri, 14 Dec 2007 11:17:21 +0100
Andi Kleen <andi@firstfloor.org> wrote:

> >so do whatever is necessary to enable dynticks.
>
> dynticks' main purpose is to save power, but C1e saves more power.
> Disabling C1e for dynticks would be a fairly useless default
> trade off.

I see. Also, AMD specs say that either higher C-states are enabled, or
C1E, but not both at the same time. So if the BIOS doesn't offer an
option to disable C1E, it can't provide _CST or P_LVL* ACPI
objects for higher C-states.

Dynticks also provides lower latencies as far as I know. I think this
workaround should be merged, even if as a non-default config option.

I'll resubmit a patch if you agree.

(By the way, sorry for messing up the "Cc:" fields in the previous
message.)