aliakseis / rb_avl_comparison

Comparing RB and AVL tree implementations. We Need To Go Deeper.

rb_avl_comparison

Comparing RB and AVL implementations

Make AVL Trees Great Again announcement

"I think I have discovered something that no one else has any idea about, and I’m not sure I can do it justice. Its scope is so broad that I can see only parts of it clearly at one time, and it is exceedingly difficult to set down comprehensibly in writing…" Jordan Peterson

RB tree:

"We developed a new red-black tree implementation that has the same low memory overhead (two pointer fields per node), but is approximately 30% faster for insertion/removal."

https://www.facebook.com/notes/facebook-engineering/scalable-memory-allocation-using-jemalloc/480222803919/

https://github.com/jemalloc/jemalloc/blob/dev/include/jemalloc/internal/rb.h

AVL tree:

http://neil.brown.name/blog/AVL - after a small modification to reduce memory hits

Just one more thing:

Please note this function.

This is how an item deletion from the tree is accelerated by lowering memory access.

10000000 nodes test

CPU E2180 @ 2.00GHz

Target: x86_64-redhat-linux gcc version 5.3.1 20160406 (Red Hat 5.3.1-6) (GCC)

sudo nice -n -20 ./main

tree_insert time: 19.4895 seconds
RB depth: 22.1559
tree_search time: 17.764 seconds
alternative tree_search time: 19.4725 seconds
tree_remove time: 23.3087 seconds

avl_insert time: 18.5318 seconds
AVL depth: 21.7497
avl_find time: 17.5718 seconds
alternative avl_find time: 19.446 seconds
avl_delete time: 22.9048 seconds

CPU i5-6600 @ 3.30GHz

Target: x86_64-linux-gnu gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.6)

sudo nice -n -20 ./main

tree_insert time: 10.375 seconds
RB depth: 22.1559
tree_search time: 9.85938 seconds
alternative tree_search time: 10.9844 seconds
tree_remove time: 12.0156 seconds

avl_insert time: 9.89062 seconds
AVL depth: 21.7497
avl_find time: 7.84375 seconds
alternative avl_find time: 7.67188 seconds
avl_delete time: 11.5781 seconds

enum { NNODES = 20 * 10000000 };

sudo nice -n -20 ./main

tree_insert time: 388.344 seconds
RB depth: 26.6402
tree_search time: 324.953 seconds
alternative tree_search time: 330.125 seconds
tree_remove time: 397.578 seconds

avl_insert time: 298.062 seconds
AVL depth: 26.0732
avl_find time: 264.625 seconds
alternative avl_find time: 267 seconds
avl_delete time: 399.719 seconds

clang version 3.8.0-2ubuntu4 (tags/RELEASE_380/final)

clang++ -Wall -O3 -std=c++11 rb_avl.cpp -o rb_avl
sudo nice -n -20 ./rb_avl

tree_insert time: 10.7969 seconds
RB depth: 22.1559
tree_search time: 10.125 seconds
alternative tree_search time: 11.0312 seconds
tree_remove time: 12.2969 seconds

avl_insert time: 10.6875 seconds
AVL depth: 21.7497
avl_find time: 5.64062 seconds
alternative avl_find time: 6.1875 seconds
avl_delete time: 12.0938 seconds