Re: [PATCH v2] sched: Check sched_domain before computing grouppower.

From: Srikar Dronamraju
Date: Thu Nov 14 2013 - 05:50:40 EST


> + /*
> + * build_sched_domains() -> init_sched_groups_power()
> + * gets here before we've attached the domains to the
> + * runqueues.
> + *
> + * Use power_of(), which is set irrespective of domains
> + * in update_cpu_power().
> + *
> + * This avoids power/power_orig from being 0 and
> + * causing divide-by-zero issues on boot.
> + *
> + * Runtime updates will correct power_orig.
> + */
> + if (!rq->sd) {

Because this condition is only true during boot up, I am now
thinking if we should do mark this as unlikely i.e if (unlikely(!rq->sd)) {

Peter,

Please do let me know if you agree and if you want to spin of a new
version?

> + power_orig += power_of(cpu);
> + power += power_of(cpu);
> + continue;
> + }
> +
> + sgp = rq->sd->groups->sgp;
> + power_orig += sgp->power_orig;
> + power += sgp->power;
> }
> } else {
> /*
>

--
Thanks and Regards
Srikar Dronamraju

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