UHD Drivers run in user space ! Nice to know

The UHD drivers all run up in user-space, and are as efficient as they can be, pretty much.  There *is* a lot of code in UHD, but very little of it is in the "critical path" in delivering samples to the applications that use those samples.  There may be some tweaks here and there, and the R&D team certainly, in my experience, takes advantage of those tweaks when possible.  But at the end of the day, you're at the mercy of what your OS can deliver and nothing in the USRP/UHD "universe" can really do much about that....