While doing some development I noticed that running the root locus tests in the unit test suite takes a long time. This occurs in control/tests/matlab_test and control/tests/rlocus_tests.py. I did a bit of checking and it appears that the root locus command rlocus is generating 15K+ points in the root locus diagram, which can take a while...

Not sure when this crept in, but it would be nice for everyone (users, developers, Travis CI) to have the number of data points be a reasonable fraction of the number of pixels across a typical screen rather than a large multiple.