| Date | Sat, 15 Aug 2015 11:46:17 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFCv5 PATCH 36/46] sched: Prevent unnecessary active balance of single task in sched group |
| |
On Tue, Jul 07, 2015 at 07:24:19PM +0100, Morten Rasmussen wrote: > Scenarios with the busiest group having just one task and the local > being idle on topologies with sched groups with different numbers of > cpus manage to dodge all load-balance bailout conditions resulting the > nr_balance_failed counter to be incremented. This eventually causes an > pointless active migration of the task. This patch prevents this by not > incrementing the counter when the busiest group only has one task. > ASYM_PACKING migrations and migrations due to reduced capacity should > still take place as these are explicitly captured by > need_active_balance(). > > A better solution would be to not attempt the load-balance in the first > place, but that requires significant changes to the order of bailout > conditions and statistics gathering.
*groan*, and this is of course triggered by your 2+3 core TC2 thingy.
Yes, asymmetric groups like that are a pain.
|