Messages in this thread | | | Date | Tue, 10 Jun 2014 13:17:32 +0200 | From | Henrik Austad <> | Subject | Re: [RFC PATCH 02/16] sched: Introduce CONFIG_SCHED_ENERGY |
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On Tue, Jun 10, 2014 at 12:23:53PM +0200, Peter Zijlstra wrote: > On Tue, Jun 10, 2014 at 11:06:41AM +0100, Morten Rasmussen wrote: > > How would you like to disable the energy stuff for users for whom > > latency is everything? > > > > I mean, we are adding some extra load/utilization tracking. While I > > think we should do everything possible to minimize the overhead, I think > > it is unrealistic to assume that it will be zero. Is a some extra 'if > > (energy_enabled)' acceptable? > > > > I'm open for other suggestions. > > We have the jump-label stuff to do self modifying code ;-) The only > thing we need to be careful with is data-layout.
Isn't this asking for trouble?
I do get the point of not introducing more make-ifdeffery, but I'm not so sure the alternative is much better. Do we really want to spend time tracing down bugs introduced via a self-modifying process in something as central as the scheduler?
> So I'm _hoping_ we can do all this without more CONFIG knobs, because > {PREEMPT*SMP*CGROUP^3*NUMA^2} is already entirely annoying to > build and run test, not to mention that distro builds will have no other > option than to enable everything anyhow.
True, but if that is the argument, how is adding this as a dynamic thing any better, you still end up with a test-matrix of the same size?
Building a kernel isn't _that_ much work and it would make the test-scripts all the much simpler to maintain if we don't have to rely on some dynamic tweaking of the core.
Just sayin'
-- Henrik Austad
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