Messages in this thread | | | Date | Sun, 15 Aug 2010 00:00:04 -0700 | From | "Paul E. McKenney" <> | Subject | Re: Attempted summary of suspend-blockers LKML thread, take three |
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On Sat, Aug 14, 2010 at 09:53:51AM -0700, Arjan van de Ven wrote: > On Sat, 14 Aug 2010 08:10:48 -0700 > "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote: > > > > So once you are down to one CPU, the last CPU shuts the system off, > > itself included? Or does the last CPU "run" in a deep idle state > > throughout suspend? (My guess is the former, and I am also curious > > whether the cache SRAMs are powered off, etc. But figured I should > > ask rather than guessing.) > > they tend to go "off". > > however I think you're making an assumption that there is a > real difference between a deep idle state and "off".... > > For modern x86 hardware, that assumption isn't really valid. > (other than a very very small sram that stores register content in the > idle case)
I am and have been taking you at your word that some systems can reach power levels while idle that rival suspended/off. The differences between idle and suspend are instead semantic, have been posted here more than once, and make themselves felt when the non-suspended system is non-idle, even for systems whose deep-idle power approximates that of suspend/off.
Thanx, Paul
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