|| ||"Paul E. McKenney" <paulmck-AT-linux.vnet.ibm.com> |
|| ||Andi Kleen <andi-AT-firstfloor.org> |
|| ||Re: [PATCH RFC nohz_full 0/7] v2 Provide infrastructure for
full-system idle |
|| ||Mon, 1 Jul 2013 12:19:49 -0700|
|| ||linux-kernel-AT-vger.kernel.org, mingo-AT-elte.hu, laijs-AT-cn.fujitsu.com,
niv-AT-us.ibm.com, tglx-AT-linutronix.de, peterz-AT-infradead.org,
rostedt-AT-goodmis.org, dhowells-AT-redhat.com, edumazet-AT-google.com,
darren-AT-dvhart.com, fweisbec-AT-gmail.com, sbw-AT-mit.edu|
|| ||Article, Thread
On Mon, Jul 01, 2013 at 06:19:10PM +0200, Andi Kleen wrote:
> > 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.
> FWIW if you want useful testing you need to enable it by default
> (as part of NO_IDLE_HZ) anyways. Users will most likely pick
> whatever is "default" in Kconfig.
At this point in the process, I want testers who choose to test. Hapless
victim testers come later. Well, other than randconfig testers, but I
consider them to be voluntary hapless victims. ;-)
> > > 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.
> What performance part?
> Are you saying this adds so many checks to hot paths that normal runtime
> if() with a flag is too expensive?
I am saying that I don't know, and that I want to make it easy for people
to find out by comparing to the base configuration -- and for me to be
able to detect this from their .config file.
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