CVS commit: src/common/lib/libc/gen

["Andrew Doran" <ad%netbsd.org@localhost>]

Module Name:    src
Committed By:   ad
Date:           Thu Dec  5 18:50:41 UTC 2019

Modified Files:
        src/common/lib/libc/gen: radixtree.c

Log Message:
Delete the counter from "struct radix_tree_node", and in the one place we
need a non-zero check, substitute with a deterministic bitwise OR of all
values in the node.  The structure then becomes cache line aligned.

For each node we now need only touch 2 cache lines instead of 3, which makes
all the operations faster (measured), amortises the cost of not having a
counter, and will avoid intra-pool-page false sharing on MP.


To generate a diff of this commit:
cvs rdiff -u -r1.18 -r1.19 src/common/lib/libc/gen/radixtree.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.