[tor-relays] Tor CPU usage

[teor]

> On 30 Jun 2017, at 04:52, Arisbe <arisbe at cni.net> wrote:
> 
> I have a small Tor exit relay (VPS) running at +90% CPU capacity.

What version of Tor?
Has this only happened recently?
Did you upgrade your Tor version?
Are you running a caching DNS server?

>  Memory usage is negligible.  I am unable to launch ARM as the single CPU cannot process both Tor and arm.  Traffic is mostly high for a small node.
> 
> I have CPUsNum set at 2 in my torrc from its original setup.

Have you tried removing this from your torrc?

> However, pidstat 5 -p <pid> shows that only 1 CPU is employed.  lscpu shows that the VPS is allotted 2 cpus.

2 cores, or hyperthreading on the same core?
Do you have any CPU masking options set?

Tor uses threads, rather than using multiple processes.

> CPU speed is around 2.44 M.
> 
> I'm hoping someone has some experience with this issue and can give me advice.

This is what I'd expect for a relay.
Cryptography is expensive.

T
--
Tim Wilson-Brown (teor)

teor2345 at gmail dot com
PGP C855 6CED 5D90 A0C5 29F6 4D43 450C BA7F 968F 094B
ricochet:ekmygaiu4rzgsk6n
xmpp: teor at torproject dot org
------------------------------------------------------------------------

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 801 bytes
Desc: Message signed with OpenPGP
URL: <http://lists.torproject.org/pipermail/tor-relays/attachments/20170630/00f7d17d/attachment.sig>