Messages in this thread | | | Date | Wed, 03 Apr 2013 13:38:20 +0800 | From | Michael Wang <> | Subject | Re: [patch v3 0/8] sched: use runnable avg in load balance |
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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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