locate: use ctx.matches instead of ctx.walk On mozilla-central, which is around 100,000 files, best of 5: $ hg --time locate > /dev/null before: real 1.460 secs (user 1.140+0.000 sys 0.320+0.000) after: real 0.620 secs (user 0.610+0.000 sys 0.020+0.000) $ hg --time locate README > /dev/null before: real 0.630 secs (user 0.330+0.000 sys 0.290+0.000) after: real 0.120 secs (user 0.110+0.000 sys 0.020+0.000) Larger repositories see correspondingly larger performance gains.