rbtree: performance and correctness test

This small module helps measure the performance of rbtree insert and
erase.

Additionally, we run a few correctness tests to check that the rbtrees
have all desired properties:

- contains the right number of nodes in the order desired,
- never two consecutive red nodes on any path,
- all paths to leaf nodes have the same number of black nodes,
- root node is black

[akpm@linux-foundation.org: fix printk warning: sparc64 cycles_t is unsigned long]
Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Santos <daniel.santos@pobox.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index b7281e4d1473..a4e5d93b0f41 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1282,6 +1282,13 @@ config LATENCYTOP
 source mm/Kconfig.debug
 source kernel/trace/Kconfig
 
+config RBTREE_TEST
+        tristate "Red-Black tree test"
+        depends on m && DEBUG_KERNEL
+        help
+          A benchmark measuring the performance of the rbtree library.
+          Also includes rbtree invariant checks.
+
 config PROVIDE_OHCI1394_DMA_INIT
         bool "Remote debugging over FireWire early on boot"
         depends on PCI && X86