Don't try to delta if target is much smaller than source
Add a new try_delta heuristic. Don't bother trying to make a delta if the target object size is much smaller (currently 1/32) than the source, as it's very likely not going to get a match. Even if it does, you will have to read at least 32x the size of the new file to reassemble it, which isn't such a good deal. This leads to a considerable performance improvement when deltifying a mix of small and large files with a very large window, because you don't have to wait for the large files to percolate out of the window before things start going fast again.
Signed-off-by: Brian Downing <firstname.lastname@example.org> Acked-by: Nicolas Pitre <email@example.com> Signed-off-by: Junio C Hamano <firstname.lastname@example.org>