Messages in this thread | | | Subject | Re: [regression] cross core scheduling frequency drop bisected to 0c313cb20732 | From | Mike Galbraith <> | Date | Sun, 10 Apr 2016 16:54:01 +0200 |
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On Sun, 2016-04-10 at 11:35 +0200, Mike Galbraith wrote: > On Sun, 2016-04-10 at 05:44 +0200, Rafael J. Wysocki wrote: > > On Sat, Apr 9, 2016 at 6:39 PM, Mike Galbraith < > > umgwanakikbuti@gmail.com> wrote: > > > > > > Hm, setting gov=performance, and taking the average of 3 30 second > > > interval PkgWatt samples as pipe-test runs.. > > > > > > 714KHz/28.03Ws = 25.46 > > > 877KHz/30.28Ws = 28.96 > > > > > > ..for pipe-test, the tradeoff look a bit more like red than green. > > > > Well, fair enough, but that's just pipe-test, and what about the > > people who don't see the performance gain and see the energy loss, > > like Doug? > > Perhaps Doug sees increased power because he's not throttling no_hz, > whereas I am, so he burns more power getting _to_ idle? Dunno, maybe > he'll try the attached. If it's a general case energy loser, so be it, > numbers talk, bs walks and all that ;-)
And here are the rest of my numbers..
> tbench 1 2 4 8 > base 752 1283 2250 3362 > > select_idle_sibling() off > 735 1344 2080 2884 > delta .977 1.047 .924 .857 > > select_idle_sibling() on, 0c313cb20732 reverted > 816 1317 2240 3388 > delta 1.085 1.026 .995 1.007 vs base > delta 1.110 .979 1.076 1.174 vs off > (^hm)
tbench 2 turboboost off base 1215 1.00 1215/32.24=37.68 revert 1252 1.03 1252/35.82=34.95=loser
tbench 2 throughput hm is apparently a turboboost oddity, and..
tbench (turboboost back on) power 1 2 4 8 base 23.88 37.41 54.64 62.25 revert 31.25 42.53 55.11 62.66
MB/s/Ws 1 2 4 8 base 31.49 34.29 41.17 54.00 revert 26.11 30.96 40.64 54.06
..while single pipe-test pair said green/green, tbench numbers say throughput green, but energy efficiency red across the board.
-Mike
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