I'm willing to accept that a London-based crypto startup (i.e. LMAX-integrated) could have a use for extreme low-latency, extreme low-variance soft-realtime C++

I'm willing to accept that a London-based crypto startup (i.e. LMAX-integrated) could have a use for extreme low-latency, extreme low-variance soft-realtime C++. In the sub-mike p99 regime you probably want to keep multithreading out of it entirely in fact. Hopefully you can accept that nitpicking the use of well-tested concurrency primitives on a forum full of impressionable up-and-coming hackers is almost certainly going to create downward pressure on sensible engineering choices amongst readers of your comments.