Messages in this thread | | | Subject | Re: [PATCH?] Livelock in pick_next_task_fair() / idle_balance() | From | Mike Galbraith <> | Date | Fri, 03 Jul 2015 06:42:32 +0200 |
| |
On Fri, 2015-07-03 at 02:42 +0800, Yuyang Du wrote:
> But still, I think, even with the above, in idle balancing, pulling until the source > rq's nr_running == 1 is not just "a short term fix", but should be there permanently > acting like a last guard with no overhead, why not.
Yeah, seems so. Searching for steal all samples... (this is all with autogroup)
load_balance: idle - s_run: 0 d_run: 2 s_load: 0 d_load: 3 imb: 23 det_tasks: 2 det_load: 3 zeros: 1 load_balance: idle - s_run: 0 d_run: 2 s_load: 0 d_load: 0 imb: 32 det_tasks: 2 det_load: 0 zeros: 2 load_balance: idle - s_run: 0 d_run: 2 s_load: 0 d_load: 1 imb: 17 det_tasks: 2 det_load: 1 zeros: 1 load_balance: idle - s_run: 0 d_run: 2 s_load: 0 d_load: 37 imb: 22 det_tasks: 2 det_load: 37 zeros: 1 load_balance: idle - s_run: 0 d_run: 2 s_load: 0 d_load: 0 imb: 102 det_tasks: 2 det_load: 0 zeros: 2
load_balance: idle - s_run: 0 d_run: 1 s_load: 0 d_load: 93 imb: 47 det_tasks: 1 det_load: 93 zeros: 0 load_balance: idle - s_run: 0 d_run: 2 s_load: 0 d_load: 202 imb: 125 det_tasks: 2 det_load: 202 zeros: 0 load_balance: idle - s_run: 0 d_run: 2 s_load: 0 d_load: 243 imb: 188 det_tasks: 2 det_load: 243 zeros: 0 load_balance: idle - s_run: 0 d_run: 1 s_load: 0 d_load: 145 imb: 73 det_tasks: 1 det_load: 145 zeros: 0 load_balance: idle - s_run: 0 d_run: 1 s_load: 0 d_load: 46 imb: 24 det_tasks: 1 det_load: 46 zeros: 0
Both varieties of total pilferage (w/wo 0 load tasks involved) seem to happen only during idle balance, never periodic (yet).
Oddity: make -j8 occasionally stacks/pulls piles of load=dinky.
homer:/sys/kernel/debug/tracing # for i in `seq 1 10`; do cat trace|grep "s_run: 1.*det_tasks: $i.*zeros: 0"|wc -l; done 71634 1567 79 15 1 3 0 2 3 0 homer:/sys/kernel/debug/tracing # cat trace|grep "s_run: 1.*det_tasks: 8.*zeros: 0" <idle>-0 [002] dNs. 594.973783: load_balance: norm - s_run: 1 d_run: 9 s_load: 67 d_load: 1110 imb: 86 det_tasks: 8 det_load: 86 zeros: 0 <...>-10367 [007] d... 1456.477281: load_balance: idle - s_run: 1 d_run: 8 s_load: 805 d_load: 22 imb: 45 det_tasks: 8 det_load: 22 zeros: 0 homer:/sys/kernel/debug/tracing # cat trace|grep "s_run: 1.*det_tasks: 9.*zeros: 0" <...>-23317 [004] d... 486.677925: load_balance: idle - s_run: 1 d_run: 9 s_load: 888 d_load: 27 imb: 47 det_tasks: 9 det_load: 27 zeros: 0 <...>-11485 [002] d... 573.411095: load_balance: idle - s_run: 1 d_run: 9 s_load: 124 d_load: 78 imb: 82 det_tasks: 9 det_load: 78 zeros: 0 <...>-23286 [000] d... 1510.378740: load_balance: idle - s_run: 1 d_run: 9 s_load: 102 d_load: 58 imb: 63 det_tasks: 9 det_load: 58 zeros: 0
| |