> I didn't see why we need do this. > > We only need to have the root level sched entities' vruntime become core > wide since we will compare vruntime for them across hyperthreads. For > sched entities on sub cfs_rqs, we never(at least, not now) compare their > vruntime outside their cfs_rqs. > The reason we need to do this is because, new tasks that gets created will have a vruntime based on the new min_vruntime and old tasks will have it based on the old min_vruntime and it can cause starvation based on how you set the min_vruntime. With this new patch, we normalize the whole tree so that new tasks and old tasks compare with the same min_vruntime.
Thanks, Vineeth
