Messages in this thread | | | Subject | Re: [RFC][PATCH 00/26] sched/numa | From | Peter Zijlstra <> | Date | Mon, 19 Mar 2012 13:20:57 +0100 |
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On Mon, 2012-03-19 at 13:42 +0200, Avi Kivity wrote: > It's the standard space/time tradeoff. Once solution wants more > storage, the other wants more faults. > > Note scanners can use A/D bits which are cheaper than faults.
I'm not convinced.. the scanner will still consume time even if the system is perfectly balanced -- it has to in order to determine this.
So sure, A/D/other page table magic can make scanners faster than faults however you only need faults when you're actually going to migrate a task. Whereas you always need to scan, even in the stable state.
So while the per-instance times might be in favour of scanning, I'm thinking the accumulated time is in favour of faults.
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