Messages in this thread | | | Subject | Re: 50 Watt idle power regression bisected to Linux-3.10 | From | Mike Galbraith <> | Date | Sat, 07 Dec 2013 20:17:16 +0100 |
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On Sat, 2013-12-07 at 11:45 -0500, Len Brown wrote: > >> It fixes that, except for my Q6600 box. Too bad mwait_idle() went away, > >> beloved old box doesn't play hints game, so it continues to flog itself. > > > Thanks for pointing this out, Mike! > > A Q6600 is a Kentsfield. I dug one of those up. > Indeed, the only idle capabilities it has are HALT > and old style MWAIT, and the latter is much more effective. > running 3.8 it idles at 75 watts. > running 3.8 with idle=nomwait it idles at 100 watts, > which is what it will do with 3.9 and later due to the patch below. > > commit 69fb3676df3329a7142803bb3502fa59dc0db2e3 > Author: Len Brown <len.brown@intel.com> > Date: Sun Feb 10 01:38:39 2013 -0500 > > x86 idle: remove mwait_idle() and "idle=mwait" cmdline param > > Kentsfield proves that patch was based on a fault assumption. > Sweet box in its day, ECC memory and everything -- probably still > a fair number of them running... > > Plus, I've found another machine that depends on having an idle=mwait > idle loop (A Sony Vaio BIOS SMM code apparently assumes we use it in > https://bugzilla.kernel.org/show_bug.cgi?id=60770) > > So it looks like I need to (also) restore the simple idle=mwait idle loop > to make some machines happy.
Cool, box will definitely be happier.
-Mike
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