Examining the VM splay tree effectiveness

Andre Oppermann andre at freebsd.org
Thu Sep 30 17:46:12 UTC 2010

On 30.09.2010 19:24, Roman Divacky wrote:
> are you aware of Summer of Code 2008 project by Mayur Shardul?

I remember that there was this project but I never saw any numbers
or other outcome of it.  Haven't checked p4 to look at the code


> quoting: http://www.freebsd.org/projects/summerofcode-2008.html
> Project: VM Algorithm Improvement
> Student: Mayur Shardul
> Mentor: Jeff Roberson
> Summary:
> A new data structure, viz. radix tree, was implemented and used for management of the resident pages. The
> objective is efficient use of memory and faster performance. The biggest challenge was to service insert requests
> on the data structure without blocking. Because of this constraint the memory allocation failures were not
> acceptable, to solve the problem the required memory was allocated at the boot time. Both the data structures were
> used in parallel to check the correctness and we also benchmarked the data structures and found that radix trees
> gave much better performance over splay trees.
> Ready to enter CVS/SVN: We will investigate some more approaches to handle allocation failures before the new data
> structure goes in CVS.

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