On 04/03/2013 12:28 PM, Alex Shi wrote:
[snip]
>
> but the patch may cause some unfairness if this/prev cpu are not burst at
> same time. So could like try the following patch?
I will try it later, some doubt below :)
[snip]
> +
> + if (cpu_rq(this_cpu)->avg_idle < sysctl_sched_migration_cost ||
> + cpu_rq(prev_cpu)->avg_idle < sysctl_sched_migration_cost)
> + burst= 1;
> +
> + /* use instant load for bursty waking up */
> + if (!burst) {
> + load = source_load(prev_cpu, idx);
> + this_load = target_load(this_cpu, idx);
> + } else {
> + load = cpu_rq(prev_cpu)->load.weight;
> + this_load = cpu_rq(this_cpu)->load.weight;
Ok, my understanding is, we want pull if 'prev_cpu' is burst, and don't
want pull if 'this_cpu' is burst, correct?
And we do this by guess the load higher or lower, is that right?
And I think target_load() is capable enough to choose the higher load,
if 'cpu_rq(cpu)->load.weight' is really higher, the results will be the
same.
So what about this:
/* prefer higher load if burst */
load = burst_prev ?
target_load(prev_cpu, idx) : source_load(prev_cpu, idx);
this_load = target_load(this_cpu, idx);
Regards,
Michael Wang
> + }
>
> /*
> * If sync wakeup then subtract the (maximum possible)
>
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