From: Jeff King <peff@peff.net>
Date: Fri, 17 Feb 2012 22:29:12 GMT
Subject: Re: git status: small difference between stating whole repository and small subdirectory
Message-ID: <20120217222912.GC31830@sigill.intra.peff.net>
In-Reply-To: <7vaa4hrtbe.fsf@alter.siamese.dyndns.org>

On Fri, Feb 17, 2012 at 02:25:25PM -0800, Junio C Hamano wrote:

> Jeff King <peff@peff.net> writes:
> 
> > That being said, we do have an index extension to store the tree sha1 of
> > whole directories (i.e., we populate it when we write a whole tree or
> > subtree into the index from the object db, and it becomes invalidated
> > when a file becomes modified). This optimization is used by things like
> > "git commit" to avoid having to recreate the same sub-trees over and
> > over when creating tree objects from the index. But we could also use it
> > here to avoid having to even read the sub-tree objects from the object
> > db.
> 
> Like b65982b (Optimize "diff-index --cached" using cache-tree, 2009-05-20)
> perhaps?

That's what I get for speaking before running "git log".

So yeah, we may be about as reasonably fast as we can go. Or maybe that
optimization isn't kicking in for some reason. I think going further
would require Piotr to do more profiling.

-Peff