From: Chris Mason <mason@suse.com>
Date: Fri, 22 Apr 2005 23:55:14 GMT
Subject: Re: [PATCH] multi item packed files
Message-ID: <200504221955.15422.mason@suse.com>
In-Reply-To: <200504221632.26278.mason@suse.com>

On Friday 22 April 2005 16:32, Chris Mason wrote:

> If I pack every 64k (uncompressed), the checkout-tree time goes down to
> 3m14s. That's a very big difference considering how stupid my code is  .git
> was only 20% smaller with 64k chunks.  I should be able to do better...I'll
> do one more run.
>

This run also packed tree files together (everything produced by write-tree 
went into a packed file), but not the commits.  I estimate I could save about 
another 168m by packing the tree files and commits into the same file with 
the blobs, but this wouldn't make any of the times below faster.

git - original (28k commits)	                packed
FS size                2,675,408k			1,723,820k
read-tree            24.45s				18.9s
checkout-cache   4m30s				3m5s
patch time	   2h30m				1h55m

The format for the packed files could be smarter, such that it didn't require 
decompressing the whole packed file to read one item.  I would guess I could 
get another 20% checkout-cache performance out of it via more tuning, and 
probably another 10% of space savings.

Of course, none of this is likely to convince you ;)  If you decide later on 
it's worthwhile, I don't think it would be difficult to add then.

-chris