Re: [RFC][PATCH 00/26] sched/numa

[Peter Zijlstra]

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.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/