[convivialdingo]

I tried replacing a DMA queue lock with lock-free CAS and it wasn't faster than a mutex or a standard rwlock.

I rewrote the entire queue with lock-free CAS to manage insertions/removals on the list and we finally got some better numbers. But not always! We found it worked best either as a single thread, or during massive contention. With a normal load it wasn't really much better.