From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 07 Jan 2009 18:59:03 GMT
Subject: Re: [PATCH v3 1/3] Implement the patience diff algorithm
Message-ID: <alpine.LFD.2.00.0901071056470.3057@localhost.localdomain>
In-Reply-To: <alpine.DEB.1.10.0901071001360.16651@alien.or.mcafeemobile.com>



On Wed, 7 Jan 2009, Davide Libenzi wrote:
> 
> xdiff allows for diffing ranges, and the most efficent method is exactly 
> how you did ;)

No, the performance problem is how it needs to re-hash everything. xdiff 
doesn't seem to have any way to use a "subset of the hash", so what the 
patience diff does is to use a subset of the mmfile, and then that will 
force all the rehashing to take place, which is kind of sad.

It would be nice (for patience diff) if it could partition the _hashes_ 
instead of partitioning the _data_. That way it wouldn't need to rehash. 
See?

		Linus