On Wed, 2007-07-25 at 16:55 -0400, Chris Snook wrote: > Chris Friesen wrote: > > Ingo Molnar wrote: > > > >> the 3s is the problem: change that to 60s! We no way want to > >> over-migrate for SMP fairness, the change i did gives us reasonable > >> long-term SMP fairness without the need for high-rate rebalancing. > > > > Actually, I do have requirements from our engineering guys for > > short-term fairness. They'd actually like decent fairness over even > > shorter intervals...1 second would be nice, 2 is acceptable. > > > > They are willing to trade off random peak performance for predictability. > > > > Chris > > > > The sysctls for CFS have nanosecond resolution. They default to > millisecond-order values, but you can set them much lower. See sched_fair.c > for > the knobs and their explanations. > > -- Chris
This is incorrect. Those knobs control local-CPU fairness granularity but have no control over fairness across CPUs. I'll do some benchmarking as Ingo suggested. tong - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
