git checkout running very slowly (>12s)

Some git operations (notably checkouts) are taking a very long time to execute. Here is a shell session which illustrates the problem.

$ time git branch foo git branch foo 0.01s user 0.00s system 77% cpu 0.016 total $ time git checkout foo Switched to branch 'foo' git checkout foo 11.73s user 0.18s system 99% cpu 11.937 total $ time git checkout master Switched to branch 'master' git checkout master 11.62s user 0.18s system 99% cpu 11.813 total $ git count-objects -v count: 953 size: 527012 in-pack: 153432 packs: 7 size-pack: 1986072 prune-packable: 0 garbage: 0

I tried doing a sparse checkout to eliminate approximately 40,000 files from the checkout, and furthermore doing git update-index --skip-worktree on a tree which contained about another 16,600 files, but neither had any noticeable effect on checkout times.

--- Andrew Cameron