Hi Ian, On Sun, 9 Jul 2006, Ian Blanes wrote: > I've been recently looking at the splay tree implementation. I've noticed > that this revision http://gcc.gnu.org/viewcvs?view=rev&revision=106584 > does a strange splaying. It does a bottom up splaying but starting at the > root (not the same that top down). It works but performs worst.
Interesting. Richard Guenther's post for the above change, which was based upon a previous proposal by Brian Makin, suggested that this patch reduced the compile-time of his tramp3d benchmark by 1%. http://gcc.gnu.org/ml/gcc-patches/2005-11/msg00294.html I appreciate that you've also benchmarked "typical" splay tree usage during a GCC boostrap. Any chance, that you could repeat your experiment but instead evaluate the behaviour of splay tree usage during a tramp3d compilation: http://www.suse.de/~rguenther/tramp3d/ Whilst your analysis demonstrates that splay_tree_splay is behaving curiously, I'm also interested in resolving the reported performance benefits of the different implementations. Thanks in advance, Roger --
