Resend: [PATCH 0/3] Clean up and optimize tree walking some more

[Linus Torvalds <torvalds@linux-foundation.org>]

Hmm.. There may be something wrong with my isp and/or email setup, but I 
never saw this one come back to me, so I'm re-sending just in case it got 
lost.. 

		Linus

On Wed, 21 Mar 2007, Linus Torvalds wrote:
> 
> This series of three patches improves blame performance on the eclipse 
> tree by about 15% in my tests by improving the tree walk a bit.
> 
>   [ Before-best-of-five: 11.649s
>     After-best-of-five:   9.675s ]
> 
> The first two patches are just boring cleanups: the first removes an 
> unnecessary field from the "name_entry" structure, because I wanted to 
> embed it into the "tree_desc" one and it was just totally redundant and I 
> felt bad about growing tree_desc more than necessary. No real code 
> changes, just replacing the use of "pathlen" with the helper function we 
> introduced ealier ("tree_entry_len()").
> 
> The second one just makes sure that we always initialize the tree_desc 
> structure with a helper function rather than doing it by hand. Again, this 
> doesn't actually change any code, although I changed the name of the "buf" 
> entry to "buffer", and the type of "size", so that we get nice compiler 
> warnings if they are used the old way by mistake.
> 
> The second patch is the largest of the lot, but really doesn't do 
> anything interesting, just preparatory cleanup.
> 
> The third patch is the one that actually changes any code, and is fairly 
> straightforward: it just switches around where we actually do the tree 
> entry parsing, which is now possible thanks to patch #2. By doing it 
> up-front, we only need to do it once (we used to have to do it both when 
> doing the "extract" *and* when doing the "update" op - now we do it only 
> once per entry, and "extract" is just about looking at the cached 
> contents).
> 
> The resulting diffstat of the tree patches ends up removing a few more 
> lines than it adds (not by a lot), but perhaps more importantly (even more 
> than the performance advantage) the code looks nicer, I think.
> 
>  builtin-fsck.c         |    5 +-
>  builtin-grep.c         |   13 +++--
>  builtin-pack-objects.c |    8 +--
>  builtin-read-tree.c    |    3 +-
>  builtin-reflog.c       |   10 ++--
>  fetch.c                |    3 +-
>  http-push.c            |    3 +-
>  list-objects.c         |    3 +-
>  merge-tree.c           |    9 ++--
>  reachable.c            |    3 +-
>  revision.c             |   12 ++---
>  tree-diff.c            |   22 +++++----
>  tree-walk.c            |  123 ++++++++++++++++++++++--------------------------
>  tree-walk.h            |   20 ++++++--
>  tree.c                 |   18 +++----
>  unpack-trees.c         |    3 +-
>  16 files changed, 125 insertions(+), 133 deletions(-)
> 
> I'm pretty sure this is all good, and it obviously passes all the tests, 
> but more importantly none of the changes were really very complicated, and 
> patch#2 (which is the big one) was set up so that the compiler would not 
> even compile code that wasn't properly converted, so it should all be 
> good.
> 
> 			Linus
>