Re: Significant performance waste in git-svn and friends

[Mike Hommey <mh@glandium.org>]

On Wed, Sep 05, 2007 at 01:40:42PM -0700, Junio C Hamano <gitster@pobox.com> wrote:
> Mike Hommey <mh@glandium.org> writes:
> 
> > The same things obviously apply to git-cvsimport and other scripts
> > calling git-hash-object a lot.
> 
> I *obviously* hate this patch, as it makes this Porcelain
> command to be aware of the internal representation too much.

The patch was not supposed to be applied. I said it was lame ;)
It was more of a proof of concept.

Anyways, thinking a bit more about it, I was wondering if it wouldn't be
a good idea to have Git.pm have a "native" implementation (by native I
mean a .so module) for low-level plumbing tools such as hash-object,
cat-file and such.

Obviously, reinventing the wheel is not good, so this native
implementation would be using a "git library" API, such as what has
been done under SoC (though I don't know if this API exposes low-level
plumbing functions)

> I wonder if letting fast-import handle the object creation is an
> option, though.

It could, probably. The reason I didn't use it is that it was way
quicker to hack a 10 lines patch to create the blobs by hand than it
would have been to fork a fast-import object at the correct place during
git-svn initialization and piping to it at the appropriate times.

My goal was only to check how faster this would make it not to fork a
git-hash-object per blob.

Mike