Re: [PATCH] i386 No-Idle-Hz aka Dynamic-Ticks 3

Marc Ballarin
2005-08-04T16:26:17Z

On Thu, 4 Aug 2005 01:22:36 +0200
Christian Leber <christian@leber.de> wrote:

> Just a few numbers:
>
> I tried it on a Laptop (Dell C810, P3m 1133 mhz) and measured the power
> usage with an external device and it stayed with or without patch at
> 27W. (HZ was at about 28)

Does your machine enter C3 state? Check the usage
in /proc/acpi/processor/CPU0/power

If usage is 0, unplug all USB peripherals (at least those connected to
uhci controllers). Also shut down sound servers.

Without C3, there won't be any power savings from lower HZ. Desktop CPUs
often don't support C3 at all.

Marc