Taskset not working over a range of cores in isolcpus
Solution 1:
After a day of frustration I've determined a solution. This behavior seems to be an artifact of the default kernel scheduler algorithm (SCHED_OTHER for this distro/kernel). Changing the process to a different algorithm eliminates the problem, isolcpus are adequately utilized across the processes/threads.
I ended up using SCHED_RR, but I also tested SCHED_FIFO and SCHED_IDLE both of which seem to work. The process can be launched with the alternative algorithm by use of the chrt utility:
$ sudo chrt -r 1 [command]
(If you want to run as non-root you can use the setcap utility to enable CAP_SYS_NICE on the binary file related to the command)