From: Davide Libenzi <davidel@xmailserver.org>
Date: Mon, 16 Oct 2006 16:42:04 GMT
Subject: Re: git-diff-tree inordinately (O(M*N)) slow on files with many changes
Message-ID: <Pine.LNX.4.64.0610160941270.7697@alien.or.mcafeemobile.com>
In-Reply-To: <87mz7wp6ek.fsf@rho.meyering.net>

On Mon, 16 Oct 2006, Jim Meyering wrote:

> Linus Torvalds <torvalds@osdl.org> wrote:
> > On Mon, 16 Oct 2006, Linus Torvalds wrote:
> ...
> > So I think xdiff has chosen too small a hash. Can you try what happens if
> > you change xdl_hashbits() (in xdiff/xutil.c) instead? Try making it return
> > a bigger value (for example, by initializing "bits" to 2 instead of 0),
> > and see if that makes a difference.
> 
> It makes no difference.
> 
> Bear in mind that there are a *lot* of duplicate lines in the files
> being compared: filtering each through "sort -u" removes 40-50k lines.

Ok, try to bring down XDL_MAX_EQLIMIT to something like 8 or 16 ...



- Davide