Messages in this thread |  | | Subject | RE: SMP cpu deep sleep | Date | Fri, 20 Aug 2004 07:30:47 -0700 | From | "Nakajima, Jun" <> |
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>From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel- >owner@vger.kernel.org] On Behalf Of Hans Kristian Rosbach >Sent: Friday, August 20, 2004 1:07 AM >To: linux-kernel@vger.kernel.org >Subject: SMP cpu deep sleep > >While reading through hotplug and speedstep patches >I came to think of a feature I think might be useful. > >In an SMP system there are several cpus, this generates >extra heat and power consuption even on idle load. >Is there a way to put all cpus but cpu1 into a kind of >deep sleep? Cpu1 would have to do all work (including irqs) >of course. > >We have a lot of SMP systems that we host, and they >are heavily used ~10 hours of the day, the rest they are >mostly idle. They could run on only 1 cpu during lenghty >idle periods. > >If it is possible to put cpus to a deeper sleep than >just the simple idle, then the kernel could make use of this.
Most SMP server systems today don't support the C-states beyond C1 (at least on x86 or x86-64, as far as I know). If your system supports that, I think it would be nice to do that.
Jun
> >It would be a cool feature. > >Sincerly > Hans K. Rosbach >
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