On Tue, Sep 10, 2013 at 5:31 PM, Mel Gorman <mgorman@xxxxxxx> wrote:
> @@ -5045,15 +5038,50 @@ static int need_active_balance(struct lb_env *env)
>
> static int active_load_balance_cpu_stop(void *data);
>
> +static int should_we_balance(struct lb_env *env)
> +{
> + struct sched_group *sg = env->sd->groups;
> + struct cpumask *sg_cpus, *sg_mask;
> + int cpu, balance_cpu = -1;
> +
> + /*
> + * In the newly idle case, we will allow all the cpu's
> + * to do the newly idle load balance.
> + */
> + if (env->idle == CPU_NEWLY_IDLE)
> + return 1;
> +
> + sg_cpus = sched_group_cpus(sg);
> + sg_mask = sched_group_mask(sg);
> + /* Try to find first idle cpu */
> + for_each_cpu_and(cpu, sg_cpus, env->cpus) {
> + if (!cpumask_test_cpu(cpu, sg_mask) || !idle_cpu(cpu))
> + continue;
> +
> + balance_cpu = cpu;
> + break;
> + }
> +
> + if (balance_cpu == -1)
> + balance_cpu = group_balance_cpu(sg);
> +
> + /*
> + * First idle cpu or the first cpu(busiest) in this sched group
> + * is eligible for doing load balancing at this and above domains.
> + */
> + return balance_cpu != env->dst_cpu;
FYI: Here is a bug reported by Dave Chinner.
https://lkml.org/lkml/2013/9/10/1
And lets see if any changes in your SpecJBB results without it.
Hillf
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