On Mon, Jul 30, 2018 at 08:08:55PM +0800, weiqi (C) wrote: > Hi Peter, > > After Commits 5d6523ebd(sched: Fix load-balance wreckage)，
That's a _6_ year old patch... and I can barely remember last week. > The jugement whether imbalance reached changed from twice to one-half. > > from > > (1) if((load * 2)> rem_load_move) > goto next; > > to > > (2) if((load / 2)> env-> load_move) > goto next; > > I'm confused about this change. > > "load*2" may be more appropriate, because if a task whose load more than > env->imbalance is moved from high load cpu to low load cpu, > > will make more imbalance. It basically goes back to what it was before (see 367456c), in that patch I (inadvertently) replaced (load.weight >> 1) with (load * 2) instead of (load / 2). I'm not entirely sure I can explain that logic at this time. Doing software archeology on it might clarify where it came from.
