Re: Comments on recursive merge..

From: Linus Torvalds <torvalds@osdl.org>
Date: Nov 9, 2005, 00:51 UTC
Message-ID: <Pine.LNX.4.64.0511081646160.3247@g5.osdl.org>
In-Reply-To: <20051109003236.GA30496@pasky.or.cz>

On Wed, 9 Nov 2005, Petr Baudis wrote:

> 
> BTW, git-show-branch is also by orders of magnitude faster (not that
> this would be any major timesaver). Median 0.006s vs. median 0.124s.

Ouch. That makes me suspicious. One reason git-merge-base is slow is because it's being pretty careful about some pathological examples of dates being just the wrong way around, and it might just be that the reason git-show-branch is faster is because it isn't doing that part right.

So yes, git-merge-base does extra work, but it does so because I think it needs to.

Junio? You even wrote the comment about the case in git-merge-base, I'm wondering whether it's a bug that we use the fast-and-cheap algorithm in git-show-branch..

Of course, arguably you can first try the fast-and-cheap thing, and if that gives a merge parent that is acceptable, why not? So maybe it's the right thing for the "let's see if this is trivial" case, but I think it might _think_ some cases are trivial that really shouldn't, because they actually have two merge parents.

		Linus