Re: [PATCH 1/3] kvm: memslots: track id_to_index changes during the insertion sort

From: Radim KrÄmÃÅ
Date: Fri Nov 14 2014 - 09:41:46 EST


2014-11-14 15:17+0100, Igor Mammedov:
> > (We'll have to change it into an interval tree, or something, if the
> > number of slots rises anyway.)
> Only if it rises to huge amount, I've played with proposed 512 memslots
> and it takes ~10000 cycles which is 5% of current heapsort overhead.
> Taking in account that it's slow path anyway, it's unlikely that there
> would be need to speedup this case even more.

Yes, your improvement is great and would work even for higher amounts.

I meant that our lookup is currently pretty sad -- O(N) that is
presumably optimized by looking at the largest regions first.

Maybe we would benefit from O(log N) lookup even with 128 memslots.
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