On Fri, Jun 24, 2016 at 03:23:37PM +0200, Vincent Guittot wrote: > > It seemed like a simple and cheap way to increase accuracy, nothing more > > behind it until the commit you referred to. > > Thanks for the clarification. > I thought that the difference should always be smaller than 1/64th of > the cfs_rq->avg.load_avg thanks to update_tg_load_avg
Right, another reason I just remembered is that it ensures: tg_weight >= cfs_rq_weight Because if this is the only task in the entire group and cfs_rq increased (but did not exceed the 1/64th threshold) you get the group weight being smaller than the entity weight, which would be weird.