Messages in this thread | | | Subject | Re: sched: context tracking demolishes pipe-test | From | Mike Galbraith <> | Date | Mon, 01 Jul 2013 08:07:55 +0200 |
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On Sun, 2013-06-30 at 23:29 +0200, Peter Zijlstra wrote:
> Yeah, who'd have thought that putting stuff in the syscall path would've > made syscalls more expensive ;-)
(careful, you'll injure my innocence, Santa and the Tooth Fairy exist!)
> But yeah, that's a _lot_ more expensive.. I'd not be surprised if more > people would find that objectionable.
Distros may want some hot patching or _something_ before doing the usual new=turn-it-on thing. Per trusty (spelled with 'c') old Q6600, the cost is pretty darn high.
-regress is my ~light regression testing config, carried forward from 3.6.32...master across all intervening trees. -regressx is plus CONFIG_RCU_USER_QS=y CONFIG_CONTEXT_TRACKING_FORCE=y -regressxx is plus full dynticks
taskset -c 3 pipe-test 1
2.6.32-regress 654.5 Khz 1.000 3.10.0-regress 652.1 Khz .996 1.000 3.10.0-regressx 476.8 Khz .728 .731 3.10.0-regressxx 275.6 Khz .421 .422
tbench
2.6.32-regress 327.502 MB/sec 1.000 3.10.0-regress 319.621 MB/sec .975 1.000 3.10.0-regressx 292.894 MB/sec .894 .916 3.10.0-regressxx 243.738 MB/sec .744 .762
netperf TCP_RR
2.6.32-regress 104041.84 Trans/sec 1.000 3.10.0-regress 94961.34 Trans/sec .912 1.000 3.10.0-regressx 82383.33 Trans/sec .791 .867 3.10.0-regressxx 61527.59 Trans/sec .591 .647
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