git-fetch per-repository speed issues

Ok, so maybe X.org is using git in an unexpected (or even wrong)
fashion. Our environment has split development across dozens of separate
repositories which match ABI interfaces. With CVS, we were able to keep
this all in one giant CVS repository with separate modules, but git
doesn't have that notion (which is mostly good). As such, we could use
cvsup or rsync to update the entire collection of modules.

With git, we'd prefer to use the git protocol instead of rsync for the
usual pack-related reasons, but that is limited to a single repository
at a time. And, it's painfully slow, even when the repository is up to
date:

$ cd lib/libXrandr
$ time git-fetch origin
...

real    0m17.035s
user    0m2.584s
sys     0m0.576s

This is a repository with 24 files and perhaps 50 revisions. Given
X.org's 307 git repositories, I'll clearly need to find a faster way
than running git-fetch on every one.

One thing I noticed was that the git+ssh syntax found in remotes files
doesn't do what I thought it did -- I assumed this would use 'git' for
fetch and 'ssh' for push, when in fact it just uses ssh for everything.
This slows down the connection process by several seconds.

-- 
keith.packard@intel.com