Messages in this thread | | | From | "Chen, Kenneth W" <> | Subject | RE: [patch] sched: auto-tune migration costs [was: Re: Industry db benchmark result on recent 2.6 kernels] | Date | Tue, 5 Apr 2005 17:08:34 -0700 |
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Ingo Molnar wrote on Sunday, April 03, 2005 11:24 PM
> great! How long does the benchmark take (hours?), and is there any way > to speed up the benchmarking (without hurting accuracy), so that > multiple migration-cost settings could be tried? Would it be possible to > try a few other values via the migration_factor boot option, in 0.5 msec > steps or so, to find the current sweet spot? It used to be at 11 msec > previously, correct?
It take days, each experiment is 5 hours. Previous experiments on 2.6.8 shows that the sweet spot was 12.5ms.
This time on 2.6.11, it got pushed into 16 ms. Results comparing to 10ms:
8 ms -0.3% 10 ms -- 12 ms +0.11% 16 ms +0.14% 20 ms +0.06%
12ms and up all has about 1.5% idle time. We are not anywhere near the limits on what the disk storage can deliver. So there is a potential to to tune/optimize the scheduler and reap these extra idle time.
- Ken
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