Re: [PATCH] rebase -i: avoid --cherry-pick when rebasing to a direct ancestor

On Saturday 20 February 2010 08:27:28 Jeff King wrote:

BTW, here's a weird data point:

$ ls -l a b -rw-r--r-- 1 thomas users 3300765 2010-02-20 12:48 a -rw-r--r-- 1 thomas users 3253762 2010-02-20 12:48 b $ time diff -u a b | wc -l 54530

real 0m0.644s user 0m0.562s sys 0m0.044s $ time git diff --no-index a b >/dev/null

real 0m22.848s user 0m21.956s sys 0m0.137s $ time git diff --no-index --patience a b >/dev/null

real 0m19.508s user 0m18.673s sys 0m0.273s

'a' and 'b' are two pnm's as per the OPs specification, I made 'a' a gradient and 'b' the same with two crosses drawn over it. You can find them at

  http://thomasrast.ch/download/slow-diff-pnms.zip

if you want to reproduce.

So what on earth does 'diff' do that makes it 35 times as fast?