Re: Repacking many disconnected blobs

From: Keith Packard <keithp@keithp.com>
Date: Jun 14, 2006, 17:55 UTC
Message-ID: <1150307715.20536.166.camel@neko.keithp.com>
In-Reply-To: <Pine.LNX.4.64.0606140826200.5498@g5.osdl.org>

On Wed, 2006-06-14 at 08:53 -0700, Linus Torvalds wrote:

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>  - You can list the objects with "most important first" order first, if 
>    you can.  That will improve locality later (the packing will try to 
>    generate the pack so that the order you gave the objects in will be a 
>    rough order of the resul - the first objects will be together at the 
>    beginning, the last objects will be at the end)

I take every ,v file and construct blobs for every revision. If I understand this correctly, I should be shuffling the revisions so I send the latest revision of every file first, then the next-latest revision. It would be somewhat easier to just send the whole list of revisions for the first file and then move to the next file, but if shuffling is what I want, I'll do that.

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>    The corollary to this is that it's better to generate the pack-file 
>    from a list of every version of a few files than it is to generate it 
>    from a few versions of every file. Ie, if you process things one file 
>    at a time, and create every object for that file, that is actually good 
>    for packing, since there will be the optimal delta opportunity.

I assumed that was the case. Fortunately, I process each file separately, so this matches my needs exactly. I should be able to report on this shortly.

-- 
keith.packard@intel.com