On Thu, 20 Aug 1998 16:27:45 -0600, Richard McRoberts
<rdm@bamboo.verinet.com> said:
> Kernel 2.1.117 makes Electric Fence very slow
> and tedious.
> Elapsed time in seconds 2.0.34 2.1.117
> ----------------------- ------ -------
> Without Electric Fence 3.82 3.72
> With Electric Fence 14.61 325.85 (!)
Back when the AVL vma tree was removed from 2.1, this same complaint was
made. I can't remember who, but somebody replied that yes, this was a
known problem, but there was new code planned to replace the AVL code to
restore the performance when we have large numbers of vmas.
Obviously, we have not done so. Are there any plans in this direction,
or do I have to replace the AVL code? I'm perfectly willing to go to
the extra effort of special casing the code so we only drop from linked
list to AVL tree when we exceed a certain threshold of vmas in a mm, to
keep the good simple-case performance we have now, but we _need_
something better than O(n) for vma lookup and insert/delete.
--Stephen
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