From: Jeff King <peff@peff.net>
Date: Sat, 17 Dec 2011 11:19:20 GMT
Subject: Re: [PATCH 1/3] use struct sha1_array in diff_tree_combined()
Message-ID: <20111217111920.GA24917@sigill.intra.peff.net>
In-Reply-To: <4EEC7A10.3080705@lsrfire.ath.cx>

On Sat, Dec 17, 2011 at 12:16:32PM +0100, René Scharfe wrote:

> >The original code is slightly more efficient, as it is able to use a
> >single malloc (because it knows the number of entries ahead of time).
> >It probably doesn't make a difference, but we could also add a
> >sha1_array_grow() for this case.
> [...]
> We coulddo that, yes.  In the case above we have the number already,
> in the other cases we'd have to count.
> 
> But I don't think it's worth it here.  ALLOC_GROW gives us 24 entries
> initially, which should be enough in most cases -- I'm not sure I
> want to see combined diff of that many tree.  And 24 times 20 bytes
> is small enough to not cause any memory allocation issues.

You're right.

I was blindly looking at the conversion without thinking about the
context. Of course if you have just a few items, it's going to be
irrelevant (my initial refactoring of sha1_array was to help speed up a
hundreds-of-thousands of sha1s case, so I think that put me in the
mindset of a large list).

Sorry for the noise.

-Peff