On 1 Jan 2015, at 07:39 , Greg Troxel g...@lexort.com wrote:
Libertas liber...@mykolab.com writes:
Some of the people at tor-...@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.
I'm more familiar with NetBSD, but hopefully my comments are helpful.
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.
It may also have something to do with TCP. A few thoughts:
* run netstat -f inet and look and the send queues. That's not really
cleanly diagnostic, but if they are all huge, it's a clue
* run netstat -m and vmstat -m (not sure those map from NetBSD). Look
for runnig out of mbufs and mbuf clusters. Perhaps bump up
NMBCLUSTERS in the kernel if it's not dynamic.
Tor 0.2.6.2-alpha (just in the process of being released) has some changes to
queuing behaviour using the KIST algorithm.
The KIST algorithm keeps the queues inside tor, and makes prioritisation
decisions from there, rather than writing as much as possible to the OS TCP
queues. I'm not sure how functional it is on *BSDs, but Nick Mathewson should
be able to comment on that. (I've cc'd tor-dev and Nick.)
teor
pgp 0xABFED1AC
hkp://pgp.mit.edu/
https://gist.github.com/teor2345/d033b8ce0a99adbc89c5
http://0bin.net/paste/Mu92kPyphK0bqmbA#Zvt3gzMrSCAwDN6GKsUk7Q8G-eG+Y+BLpe7wtm
U66Mx
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