Re: [PATCH 0/3] batch blob diff generation

> > Whether it's unusably inefficient depends on what you throw at it. IIRC,
> > the performance difference for pack-objects on git.git was fairly
> > negligible. The problem in linux.git is that besides being big, it has a
> > deep(er) directory structure. So collecting all of the attributes for a
> > file like drivers/gpu/drm/foo/bar.h needs to open all of those
> > intermediate trees.
> >
> > So I'd be inclined to leave it in place, in case somebody is actually
> > happily using it.
> >
> > GIT_ATTR_SOURCE suffers all of the same problems; it's just that you'd
> > presumably only use it with a few select commands (as far as I know,
> > pack-objects is the worst case because it's looking up one attribute on
> > every single blob in all of history).
> 
> Ah, OK.  So your "caution" was about the underlying mechanism to
> allow attributes corrected from the specified tree, and not
> specifically about using "attr.tree" to specify that tree?  That was
> what got me confused.
> 
> If that is the case, I do not think the documentation patch that
> started this exchange that adds attr.tree to where GIT_ATTR_SOURCE
> and --attr-source are already mentioned makes anything worse.