I got several long private emails from Theo De Raadt about this issue. I think the gist of it all is that most likely (a) the app most likely shouldn't be calling os.urandom() that often, and (b) Solaris getentropy() is apparently stunningly slow. Theo also seems to imply that "entropy" as a concept is debunked, and OpenBSD getentropy() and getrandom() are essentially the same thing except that the former's interface is faster (because it doesn't use a FD). So it is also possible that using getentropy() instead of getrandom() was unnecessary; possibly the speed difference would be noticeable via Python. Perhaps the getentropy() check can explicitly rule out Solaris (either at the autoconf level or in the random.c source code) if you prefer to keep the getentropy() call on OpenBSD.