From: Jeff King <peff@peff.net>
Date: Tue, 18 Sep 2007 09:01:05 GMT
Subject: Re: diffcore-rename performance mode
Message-ID: <20070918090105.GA11854@coredump.intra.peff.net>
In-Reply-To: <7vhclswdsm.fsf@gitster.siamese.dyndns.org>

On Tue, Sep 18, 2007 at 01:58:17AM -0700, Junio C Hamano wrote:

> > I thought we were holding counts of hashes, in which case there _is_ no
> > overflow.
> 
> The raw hashval (the fingerprint recorded in struct spanhash) is
> further reduced and used as an index into spahash_top.data[].
> So more than one hashval can try to sit in the same slot in
> spanhash_top.data[] array.

Right, that's sort of what I was hinting at in the original message. Can
we just make the hash table big enough to use the fingerprint hashes
directly? It's going to use a bit more memory, but lookups should be
very fast. I'll try to experiment and get some numbers.

-Peff