Messages in this thread | | | Date | Tue, 16 Sep 2014 10:00:58 -0700 | From | Dietmar Eggemann <> | Subject | Re: [PATCH v5 11/12] sched: replace capacity_factor by utilization |
| |
On 14/09/14 12:41, Peter Zijlstra wrote: > On Thu, Sep 11, 2014 at 07:26:48PM +0200, Vincent Guittot wrote: >> On 11 September 2014 18:15, Peter Zijlstra <peterz@infradead.org> wrote: >>> On Tue, Aug 26, 2014 at 01:06:54PM +0200, Vincent Guittot wrote: >>>> +static inline int group_has_free_capacity(struct sg_lb_stats *sgs, >>>> + struct lb_env *env) >>>> { >>>> + if ((sgs->group_capacity_orig * 100) > >>>> + (sgs->group_utilization * env->sd->imbalance_pct)) >>>> + return 1; >>>> + >>>> + if (sgs->sum_nr_running < sgs->group_weight) >>>> + return 1; >>>> >>>> + return 0; >>>> +} >>>> >>>> +static inline int group_is_overloaded(struct sg_lb_stats *sgs, >>>> + struct lb_env *env) >>>> +{ >>>> + if (sgs->sum_nr_running <= sgs->group_weight) >>>> + return 0; >>>> >>>> + if ((sgs->group_capacity_orig * 100) < >>>> + (sgs->group_utilization * env->sd->imbalance_pct)) >>>> + return 1; >>>> >>>> + return 0; >>>> } >>> >>> I'm confused about the utilization vs capacity_orig. I see how we should >> >> 1st point is that I should compare utilization vs capacity and not >> capacity_orig. >> I should have replaced capacity_orig by capacity in the functions >> above when i move the utilization statistic from >> rq->avg.runnable_avg_sum to cfs.usage_load_avg. >> rq->avg.runnable_avg_sum was measuring all activity on the cpu whereas >> cfs.usage_load_avg integrates only cfs tasks >> >> With this change, we don't need sgs->group_capacity_orig anymore but >> only sgs->group_capacity. So sgs->group_capacity_orig can be removed >> as it's no more used in the code as sg_capacity_factor has been >> removed > > Yes, but.. so I suppose we need to add DVFS accounting and remove > cpufreq from the capacity thing. Otherwise I don't see it make sense.
My understanding is that uArch scaling of capacacity_orig (therefore of capacity too) is done by calling arch_scale_cpu_capacity and frequency scaling for capacity is done by calling arch_scale_freq_capacity in update_cpu_capacity. I understand that this patch-set does not provide an implementation of arch_scale_freq_capacity though.
The uArch and frequency scaling of load & utilization will be added later. I know that Morten is currently working on a 'uArch and frequency invariant load & utilization tracking' patch-set.
Although I don't know exactly what you mean by DVFS accounting and remove cpufreq from the capacity here.
-- Dietmar
> -- > 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/ >
| |