From: Junio C Hamano Date: Fri, 24 Feb 2006 20:53:05 GMT Subject: Re: [PATCH] diff-delta: produce optimal pack data Message-ID: <7vpslc8oni.fsf@assigned-by-dhcp.cox.net> In-Reply-To: Linus Torvalds writes: > NOTE! Every SINGLE one of those heuristics are just totally made up by > yours truly, and have no testing behind them. They're more of the type > "that sounds about right" than "this is how it must be". As mentioned, > Nico has already been playing with the heuristics - but he wanted better > packs, not better CPU usage, so he went the other way from what you would > want to try.. I haven't looked at Nico's original or updated code closely at all, but two things come to mind. (1) if we could tell the particular data is intrinsically diff_delta unfriendly and diff_delta would waste too much time when tried to delta against almost _any_ other blob, then it might help to give an interface in diff-delta.c for the caller to check for such a blob without even trying diff_delta. (2) otherwise, if diff_delta could detect it would spend too many cycles to finish its work for a particular input early on, we might want it to bail out instead of trying a complete job.