numa,sched: fix load_to_imbalanced logic inversion
This function is supposed to return true if the new load imbalance is
worse than the old one. It didn't. I can only hope brown paper bags
are in style.
Now things converge much better on both the 4 node and 8 node systems.
I am not sure why this did not seem to impact specjbb performance on the
4 node system, which is the system I have full-time access to.
This bug was introduced recently, with commit e63da03639cc ("sched/numa:
Allow task switch if load imbalance improves")
Signed-off-by: Rik van Riel <firstname.lastname@example.org>
Signed-off-by: Linus Torvalds <email@example.com>
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 17de195..9855e87 100644
@@ -1120,7 +1120,7 @@
old_imb = orig_dst_load * 100 - orig_src_load * env->imbalance_pct;
/* Would this change make things worse? */
- return (old_imb > imb);
+ return (imb > old_imb);