Why is "git tag --contains" so slow?

Why is "git tag --contains" so slow?

On Mon, Jul 05, 2010 at 08:27:23AM -0400, Jeff King wrote:

> As you probably guessed from the specificity of the number, I wrote a
> short program to actually traverse and find the worst skew. It takes
> about 5 seconds to run (unsurprisingly, since it is doing the same full
> traversal that we end up doing in the above numbers). So we could
> "autoskew" by setting up the configuration on clone, and then
> periodically updating it as part of "git gc".

This patch doesn't implement auto-detection of skew, but is the program
I used to calculate, and would provide the basis for such
auto-detection. It would be interesting to see average skew numbers for
popular repositories. You can run it as "git skew --all".

Signed-off-by: Junio C Hamano <gitster@pobox.com>