That, and because they need to be tuned for each individual cache line size. See http://nothings.org/computer/judy/ http://nothings.org/computer/judy/ for a mo

That, and because they need to be tuned for each individual cache line size. See http://nothings.org/computer/judy/ http://nothings.org/computer/judy/ for a more thorough analysis of Judy arrays (at 20 kLoC) versus straightforward hash tables (at 0.2 kLoC).