On Wed, Jul 23, 2008 at 05:59:01PM +0000, Linus Torvalds wrote:
> In fact, the two top entries in a profile look roughly like:
>
> 102161 70.2727 libz.so.1.2.3 libz.so.1.2.3 (no symbols)
> 7685 5.2862 git git find_pack_entry_one
> ...
>
> ie 70% of the time is just purely unpacking the data, and another 5% is
> just finding it. We could perhaps improve on it, but not a whole lot.
Well there is an easy way though, that could reduce that: using
adaptative compression. I proposed a patch once upon a time, that set
the compression strengh to 0 for "small" objects with a configurable
cut-off. If you do that, most trees, commits messages and so on aren't
compressed, and it will reduce (with IIRC a 5-liner) this time quite
dramatically.
I could maybe resurect it to see if for people that do the kind of
things Ingo does it helps. By setting the cut-off at 1k, I had packs
being less than 1% bigger IIRC. I'll try to find it again and run your
tests with it to see how much it helps.
[ Of course, it doesn't invalidate the rest of your mail about being
more clever with git-merge, but still, we could reduce this 70% of
zlib time quite a lot with that ]
--
·O· Pierre Habouzit
··O madcoder@xxxxxxxxxx
OOO http://www.madism.org
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