I saw I can change what CPUs different IRQs are bound to. I saw that a given Ethernet port has like 16 entries. I don’t see a way to set CPU affinity for any processes running such as BTest. Sure enough, when I run BTest, it runs on the same CPU as one of the interfaces is running on, neutering my max speed. I can fill a 10GigE interface bidirectionally (19.4 gbit) with a BTest with something like 15% CPU usage, but I can only get 23.2 gigabit when I do another because the core btest runs on runs out of steam.
No, I don’t have another set of boxes with an equal number of 10GigE to just run iperf on. I have 16x Xeon cores.