# Whenever the pool drops to 128 it should very quickly be refilled
watch -n 0.1 cat /proc/sys/kernel/random/entropy_avail
# For extra fun, try this both with and without netrng running:
cat /dev/random | pv -bart > /dev/null
# For me this measures 13KB/s with netrng running
# but only small numbers of B/s rapidly dropping towards zero with netrng stopped