$ git clone https://github.com/RoboticsHS/rospkg
$ cd rospkg
$ stack build
$ time ./.stack-work/install/x86_64-linux/lts-6.14/7.10.3/bin/rospkg list > /dev/null
0,09s user 0,04s system 195% cpu 0,070 total
$ time rospack list > /dev/null
0,30s user 0,28s system 99% cpu 0,585 total
$ time ./.stack-work/install/x86_64-linux/lts-6.14/7.10.3/bin/rospkg find geometry_msgs > /dev/null
0,01s user 0,00s system 84% cpu 0,011 total
$ time rospack find geometry_msgs > /dev/null
0,02s user 0,01s system 95% cpu 0,025 total