So nothing really got done this weekend. It wouldn't have helped to run the benchmarks without having the analysis code I wanted to use the benchmarks as testcases for ready for the occasion. Reimplementing math libraries there aren't free equivalents of is a big PITA.
I got a real profile instead of a description and the signs point to too many calls to add_timer(), mod_timer(), and del_timer() as opposed to cache-blowing in cascade_timers(), which surprised me but relieves me of the burden of writing the umpteenth priority queue. It also appears to be specific to ip_conntrack which I'm not sure is one of my priorities.
Following the yellow brick profile...