On Fri, 14 Dec 2007 17:35:13 -0500 Chuck Ebbert <[EMAIL PROTECTED]> wrote:
> On 12/14/2007 05:17 AM, Andi Kleen 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. > > > > What about machines where the BIOS has disabled C1e on CPU 0 but > left it enabled on CPU 1 ?? Do you mean Linux should enable C1E on CPU 0 if it's detected on CPU 1? C3 + dynticks make up a better power saver than simply C1E, as far as I know. Higher C-states should be enabled on such CPUs, as AMD docs say firmware should either enable C1E or C2 & C3 (it must provide one of these mutually exclusive options). I take having C1E on the second CPU but not the first as an attempt on BIOS's part to provide higher C-states instead of the former. How broken is it, really? But maybe someone with access to such hardware can tell us what happens: does he get C2/C3 power states under such circumstances? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
