As Jtsummers pointed out downthread, hg grep searches all revisions by default. No wonder it's so slow. $ time hg grep --rev tip CUDA > /dev/null real 0m0

As Jtsummers pointed out downthread, hg grep searches all revisions by default. No wonder it's so slow. $ time hg grep --rev tip CUDA > /dev/null real 0m0.075s user 0m0.055s sys 0m0.020s Much better. Still much slower than git, which doesn't matter for this small repo but would definitely matter on a larger repo. But better. And hg lets you define aliases, so you don't have to remember to type "--rev tip".