Messages in this thread | | | Subject | Re: cpuidle asymmetry (was Re: [RFC PATCH V4 5/5] cpuidle: cpuidle driver for apm) | From | Peter Zijlstra <> | Date | Fri, 01 Apr 2011 16:02:36 +0200 |
| |
On Fri, 2011-04-01 at 00:09 -0400, Len Brown wrote: > > > Moorestown is already an example of an asymmetric system, > > > since its deepest c-state is available on cpu0, but not on cpu1. > > > So it needs different tables for each cpu. > > > > wtf are these hardware guys smoking and how the heck are we supposed to > > schedule on such a machine? Prefer to keep cpu1 busy while idling cpu0? > > they are smoking micro-amps:-)
Has anybody told them that pushing lots of logic into software generally burns more amps because it keeps the thing running longer?
> S0i3 on cpu0 can be entered only after cpu1 is already off-line, > among other system hardware dependencies... > > So it makes no sense to export S0i3 as a c-state on cpu1. > > When cpu1 is online, the scheduler treats it as a normal SMP.
Dipankar's reply seems to address this issue well.
| |