Messages in this thread | | | Date | Mon, 1 Jul 2013 09:03:14 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH RFC nohz_full 0/7] v2 Provide infrastructure for full-system idle |
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On Mon, Jul 01, 2013 at 08:19:25AM -0700, Andi Kleen wrote: > "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> writes: > > > > The individual patches are as follows: > > > > 1. Add a CONFIG_NO_HZ_FULL_SYSIDLE Kconfig parameter to enable > > this feature. Kernels built with CONFIG_NO_HZ_FULL_SYSIDLE=n > > act exactly as they do today. > > Is this extra CONFIG option really needed? RCU already has a bewildering > variety of CONFIG options, and no idle CONFIG is also pretty complicated. > At some point noone will know how to configure kernels anymore if > these non trivial, complicated trade off CONFIGs keep spreading. > > The facility sounds like a good thing in general. Just enable > it implicitely with NO_HZ_SYSIDLE ?
I am guessing that you want CONFIG_NO_HZ_FULL to implicitly enable the sysidle code so that CONFIG_NO_HZ_FULL_SYSIDLE can be eliminated. I will be happy to take that step, but only after I gain full confidence in the correctness and performance of the sysidle code.
> If you want a switch for testing I would advise a sysctl or sysfs knob
This would work well for the correctness part, but not for the performance part.
Thanx, Paul
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