[tor-relays] Does Tor work with Intel QAT acceleration

Tue Apr 12 14:23:00 UTC 2022

Hi Andreas

According to [0] QAT supports:

  * RSA with 2048, 3072, and 4096 bit keys
  * ECDH for the Montgomery Curve X25519 and NIST Prime Curves P-256 and
    P-384
  * ECDSA for the NIST Prime Curves P-256 and P-384
  * AES-GCM with 128, 192, and 256 bit keys

The tor-spec [1] shows that Tor only uses RSA with 1024 Bit Keys and the 
ciphersuits only contain AES CBC and no AES GCM ones. I'm not an expert 
but it looks like it's not that useful for Tor.

Tor doesn't scale well with multiple CPU cores but you can run 2 relays 
per IP to better use your hardware. On Debian / Ubuntu you can use 
tor-instance-create <name> to create multiple relays on the same host.

[0]: 
https://www.intel.com/content/www/us/en/developer/articles/guide/building-software-acceleration-features-in-the-intel-qat-engine-for-openssl.html 

[1]: https://gitweb.torproject.org/torspec.git/tree/tor-spec.txt

Regards
Stefan

On 11.04.22 21:13, Andreas Bollhalder wrote:
> Hello Kevin
>
> Thanks a lot for your response.
>
> 1) Regarding the speedtest, my firewall is limiting the speed to 
> around 6.5Gbit/s. It's a fanless device and not capable to let me use 
> the full 10Gbit/s. I host my hardware in my living room and can't 
> install more powerfull, beacuse it would be too noisy and too big... 
> My wife and kids will kill me :-)
>
> 2) For the NIC currently in use: it's an Intel I219-LM (rev 10). Maybe 
> the are better models around. But I don't believe, they would lower 
> the CPU usage by magnitude(s). But I let me educate if I'm wrong.
>
> 3) The CPU in use has the AES-NI flag set in "/proc/cpuinfo". So a 
> litte acceleration is already in use.
>
> In the old days when using pfSense on a PC Engines Alix, I was using a 
> mini PCI crypto accelerator card. And it could double or tripple the 
> OpenVPN speed. So it seemed to me, that QAT could do the same for Tor.
>
> Andreas
>
> On Monday, April 11, 2022 15:58 CEST, Thoughts 
> <thoughts at kevinsthoughts.com> wrote:
>> Two suggestions:
>>
>> 1)  Run speedtest (https://www.speedtest.net) from behind your firewall
>> and verify your actual bandwidth (or at least get a good approximation
>> <smile>).
>>
>> 2)  Check the brand of NIC in your current machine.  Intel NICs are
>> reportedly much more efficient than RealTek for handling large number of
>> packets - which is why they are recommended for most firewall machines.
>> Suspect that logic would apply for a Tor Relay as well.
>>
>> Suspect you also want a CPU with AES-NI support.  Check the specs on the
>> web, AES-NI should be called out.  "cat /proc/cpuinfo | grep aes" will
>> also tell you if your running some flavor of linux.
>>
>> Kevin
>>
>> ps. Dig around on the web for firewall hardware recommendations. I know
>> I've seen some tables on throughput for pfsense, shouldn't be too hard
>> to find and might throw some light on the situation.
>>
>> pps.  Very jealous of your connectivity!
>>
>> On 4/10/2022 2:32 PM, Andreas Bollhalder wrote:
>> > Hi all
>> >
>> > I have my first Tor relay up und running. It's currently installed on
>> > a little desktop computer with an Intel i5 9500T CPU. My Internet
>> > connection is 10Gb/s symetric. From this bandwidth, I would be able to
>> > spend a good part for supporting the Tor network.
>> >
>> > With that little machine, it seems that it would max out at somewhere
>> > at ~30 MBytes/s. For my definitive Tor relay hardware, I'm currently
>> > researching some options, which would be capable of handling Tor
>> > traffic at the rate of 200 to 300MBytes. Even it would be used
>> > nowadays, but who knows whats coming in the future and I hope this
>> > relay would last 5 years ore so.
>> >
>> > It looks to me, that with a normal CPU, it's impossible to reach my
>> > goal. But then I encountered, that Intel has the Quick Assist
>> > Technoloy (QAT) integrated in some of their products (ie. Atom C3xx8).
>> > This QAT can be used with OpenSSL as a hardware accelerator for
>> > encryption. There also exist dedicated PCIe cards with QAT (ie.
>> > Netgate CPIC-8955).
>> >
>> > Searching the Internet, I couldn't find any information if QAT would
>> > be helpful with Tor. But Tor uses the OpenSSL library and this can use
>> > the QAT acceleration. Is there anyone who has tried this und can share
>> > his expirience?
>> >
>> > Thanks in advance
>> > Andreas
>> >
>> > _______________________________________________
>> > tor-relays mailing list
>> > tor-relays at lists.torproject.org
>> > https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays
>> _______________________________________________
>> tor-relays mailing list
>> tor-relays at lists.torproject.org
>> https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays
>
>
>
> _______________________________________________
> tor-relays mailing list
> tor-relays at lists.torproject.org
> https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.torproject.org/pipermail/tor-relays/attachments/20220412/57bb63b5/attachment.htm>