[Tor-BSD] Recognizing Randomness Exhaustion

[Libertas]

Some of the people at tor-bsd at lists.nycbug.org and I are trying to
figure out why Tor relays under-perform when running on OpenBSD. Many
such relays aren't even close to being network-bound,
file-descriptor-bound, memory-bound, or CPU-bound, but relay at least
33-50% less traffic than would be expected of a Linux machine in the
same situation.

For those not familiar, a Tor relay will eventually have an open TCP
connection for each of the other >6,000 active relays, and (if it allows
exit traffic) must make outside TCP connections for the user's requests,
so it's pretty file-hungry and crypto-intensive.

One possible explanation is that its randomness store gets exhausted. I
once saw errors like this in my Tor logs, but I don't know how to test
if it's a chronic problem. I also couldn't find anything online. Is
there any easy way to test if this is the bottleneck?