bookmarks: prefetch 'lookup' outside of the loop Skipping the attribute lookup up raise a significant speedup. Example on a repository with about 4000 bookmarks. Before: ! wall 0.026027 comb 0.020000 user 0.020000 sys 0.000000 (best of 112) After: ! wall 0.021580 comb 0.020000 user 0.020000 sys 0.000000 (best of 134) (This is also in its own changeset to clarify the perf win from another coming changesets)