Re: absurdly slow git-diff

On Fri, Nov 07, 2008 at 09:37:29PM +0000, Linus Torvalds wrote:

On Sat, 8 Nov 2008, Abhijit Menon-Sen wrote:

quoted

If anyone's interested, the files are http://toroid.org/misc/1 and
http://toroid.org/misc/2

I'm also adding Pierre, since he was talking about trying to implement
another diff algorithm (although I'm not at all sure that the patience 
diff really would help this case at all).

FWIW Patience diff wouldn't help at all here. Patience diff is just a
matter of preseeding your preferred diff algorithm with better (wrt
human readability) candidate for the invariant lines. IOW it helps
dividing the problem into smaller bits, but requires *unique lines* to
start with. If you haven't any, then basically, Patience diff does
nothing and calls your usual diff algorithm on the whole files.

It does so in a pseudo linear complexity, hence should not make overall
time really worse, but will not help for the ending time usually either.

-- 
·O·  Pierre Habouzit
··O                                                madcoder@debian.org
OOO                                                http://www.madism.org