|From:||Michel Lespinasse <firstname.lastname@example.org>|
|To:||email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org|
|Subject:||[PATCH v2 00/12] rbtree updates|
|Date:||Thu, 12 Jul 2012 17:31:45 -0700|
|Cc:||email@example.com, firstname.lastname@example.org, email@example.com|
Change log since v1: - Added tree graphs as comments as suggested by Peter - Fixed coding style in rest of lib/rbtree.c as suggested by Peter - made clear rb_parent_color is private, not to be directly accessed, by renaming it to __rb_parent_color - collapsed some low level optimization patches instead of splitting out the parts that were related to tree rotatoins from the parts that were related to color flips. - Added build system support in patch 5 These are quite minor changes against v1, which already got good reviews from Peter, so I think all that is required now is for Andrea to say he doesn't oppose this. -- I recently started looking at the rbtree code (with an eye towards improving the augmented rbtree support, but I haven't gotten there yet). I noticed a lot of possible speed improvements, which I am now proposing in this patch set. Patches 1-4 are preparatory: remove internal functions from rbtree.h so that users won't be tempted to use them instead of the documented APIs, clean up some incorrect usages I've noticed (in particular, with the recently added fs/proc/proc_sysctl.c rbtree usage), reference the documentation so that people have one less excuse to miss it, etc. Patch 5 is a small module I wrote to check the rbtree performance. It creates 100 nodes with random keys and repeatedly inserts and erases them from an rbtree. Additionally, it has code to check for rbtree invariants after each insert or erase operation. Patches 6-12 is where the rbtree optimizations are done, and they touch only that one file, lib/rbtree.c . I am getting good results out of these - in my small benchmark doing rbtree insertion (including search) and erase, I'm seeing a 30% runtime reduction on Sandybridge E5, which is more than I initially thought would be possible. (the results aren't as impressive on my two other test hosts though, AMD barcelona and Intel Westmere, where I am seeing 14% runtime reduction only). The code size - both source (ommiting comments) and compiled - is also shorter after these changes. However, I do admit that the updated code is more arduous to read - one big reason for that is the removal of the tree rotation helpers, which added some overhead but also made it easier to reason about things locally. Overall, I believe this is an acceptable compromise, given that this code doesn't get modified very often, and that I have good tests for it. Upon Peter's suggestion, I added comments showing the rtree configuration before every rotation. I think they help; however it's still best to have a copy of the cormen/leiserson/rivest book when digging into this code. This patchset is against v3.4. This code doesn't change very often, so the patchset should apply to the latest and greatest too. My proposal would be for this to go in -mm tree to be used as a base to add on the augmented rbtree support enhancements, which I am already working on. Michel Lespinasse (12): rbtree: reference Documentation/rbtree.txt for usage instructions rbtree: empty nodes have no color rbtree: fix incorrect rbtree node insertion in fs/proc/proc_sysctl.c rbtree: move some implementation details from rbtree.h to rbtree.c rbtree: performance and correctness test rbtree: break out of rb_insert_color loop after tree rotation rbtree: adjust root color in rb_insert_color() only when necessary rbtree: low level optimizations in rb_insert_color() rbtree: adjust node color in __rb_erase_color() only when necessary rbtree: optimize case selection logic in __rb_erase_color() rbtree: low level optimizations in __rb_erase_color() rbtree: coding style adjustments Makefile | 2 +- fs/proc/proc_sysctl.c | 5 +- include/linux/rbtree.h | 112 ++--------- include/linux/timerqueue.h | 2 +- lib/Kconfig.debug | 1 + lib/rbtree.c | 487 ++++++++++++++++++++++++++++---------------- tests/Kconfig | 18 ++ tests/Makefile | 1 + tests/rbtree_test.c | 135 ++++++++++++ 9 files changed, 487 insertions(+), 276 deletions(-) create mode 100644 tests/Kconfig create mode 100644 tests/Makefile create mode 100644 tests/rbtree_test.c -- 22.214.171.124 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to firstname.lastname@example.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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