Messages in this thread |  | | Date | Sun, 23 Nov 2014 09:03:16 +0800 | From | Wanpeng Li <> | Subject | Re: [PATCH v7 6/7] sched: replace capacity_factor by usage |
| |
Hi Vincent, On 10/9/14, 10:18 PM, Vincent Guittot wrote: > On 9 October 2014 14:16, Peter Zijlstra <peterz@infradead.org> wrote: >> On Tue, Oct 07, 2014 at 02:13:36PM +0200, Vincent Guittot wrote: >>> +static inline bool >>> +group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs) >>> { >>> + if ((sgs->group_capacity * 100) > >>> + (sgs->group_usage * env->sd->imbalance_pct)) >>> + return true; >> Why the imb_pct there? We're looking for 100% utilization, not 130 or >> whatnot, right? > Having exactly 100% is quite difficult because of various rounding.
Could you give some examples about the various rounding?
Regards, Wanpeng Li
> So i have added a margin/threshold to prevent any excessive change of the state. > I have just to use the same margin/threshold than in other place in > load balance. > > so the current threshold depends of the sched_level. it's around 14% at MC level > >>> + if (sgs->sum_nr_running < sgs->group_weight) >>> + return true; >> With the code as it stands, this is the cheaper test (no mults) so why >> is it second? >> >>> + return false; >>> +} >>> >>> +static inline bool >>> +group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs) >>> +{ >>> + if (sgs->sum_nr_running <= sgs->group_weight) >>> + return false; >>> + >>> + if ((sgs->group_capacity * 100) < >>> + (sgs->group_usage * env->sd->imbalance_pct)) >>> + return true; >>> >>> + return false; >>> } >> Same thing here wrt imb_pct > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
|  |