Re: [PATCH 2/2] serialize collection of refs that contain submodule changes

> Here are some numbers (using the my development clone of git
> itself) from my local machine:
> 
> rm -rf <test-git> && mkdir <test-git> &&
> (cd <test-git> && git init) &&
> time git push --mirror <test-git>
> 
>    real	0m16.056s
>    user	0m24.424s
>    sys	0m1.380s
> 
>    real	0m15.885s
>    user	0m24.204s
>    sys	0m1.296s
> 
>    real	0m16.731s
>    user	0m24.176s
>    sys	0m1.244s
> 
> rm -rf <test-git> && mkdir <test-git> &&
> (cd <test-git> && git init) &&
> time git push --mirror --recurse-submodules=check <test-git>
> 
>    real	0m21.441s
>    user	0m29.560s
>    sys	0m1.480s
> 
>    real	0m21.319s
>    user	0m29.484s
>    sys	0m1.464s
> 
>    real	0m21.261s
>    user	0m29.252s
>    sys	0m1.592s
> 
> Without my patches and --recurse-submodules=check the numbers are
> basically the same. I stopped the test with --recurse-submodules=check
> after ~ 9 minutes.