On Thu, 2013-02-07 at 20:07 +0100, Ingo Molnar wrote: > Could we just simplify things and make this an unconditional > option of NO_HZ? Any reason why we'd want to make this > configurable, other than debugging?
I think the worry is the overhead that is required to keep it active. It requires the context_tracking being enabled. Although, we may be able to have both working. Frederic, can we switch between context_tracking timing and tick base at run time? If we can have it enabled without overhead then I see no problem with it. We still need the boot time kernel parameter to implement it. Hmm, even if we can't dynamically switch between context_tracking and tick base, we could make that decision at boot up based off of the kernel parameters. > > I'm worried about the proliferation of not easily separable > config options. We already have way too many timer and scheduler > options to begin with. I agree. > > > At least for now we seem to agree on CONFIG_NO_HZ_IDLE and > > keep CONFIG_NO_HZ for compatibility. Are you ok with that? If > > so I'll send a patch. > > What would be the name of the new config option? > > Can we just keep CONFIG_NO_HZ and extend it with your bits, and > make sure they work well? As long as we do not introduce performance regressions. If we can keep it active without causing the system to slow down when not in use, then I think it should be always enabled if CONFIG_NO_HZ is selected. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/