Hi

I think Tor is using libraries for this functions. If the libraries in question 
supports QAT, then it should accelerate Tor too. If the libraries don't support 
QAT, then maybe it could be replaced by a library supporting it.

In older days, I've seen configuration options in programs to activate hardware 
acceleartion of the library, setting environment variables for the library or 
other ways of control.

Cheers
Andreas

On Saturday, June 22, 2024 23:14 CEST, mail--- via tor-relays 
<tor-relays@lists.torproject.org> wrote:
  Hi o/, During the Tor Operator Meetup I asked about Quick Assist Technology 
(QAT) support and was asked to bring it to the tor-relays mailing list so the 
network team can take a look at the question. In 2025 we're going to build one 
or more new servers and we're looking in to optimizing the performance per watt 
ratio since some of our current servers are rather power hungry ;-). I'm 
wondering whether QAT works for Tor to offload compression, hashing and 
encryption. In theory, looking at the nature of Tor (a lot encryption), this 
could result in a huge performance boost of 100-300% (based on other hashing, 
cryptographic and compression offload benchmarks). Support for QAT also has 
improved considerably over the years so many programs/workloads already work 
nicely with it, but I'm not sure about Tor. It looks like Tor uses [1] 
RSA-1024, AES-CBC, AES-CTR, Curve25519, Ed25519, SHA1, AES256, AES3-256. Most 
(no Curve- and Ed25519) should in theory also work with QAT [2] (although I 
guess only a few would impact performance significantly when offloaded). But 
the question is: does it really work? If not, what would be needed to make it 
work? Are there Tor operators who already utilize QAT? Does the Network Team 
have some insight in to this? :) Some of the potential advantages when 
comparing a similar amount of traffic:- Lower power consumption (much cheaper 
to run in expensive European countries).- Less CPU cycles required (= cheaper 
CPUs).- Less heat/cooling required (easier to put in distribution boxes and 
other small places).- Smaller physical footprint (easier to put in distribution 
boxes and other small places).- Alleviates some of the issues and challenges 
caused by Tor's single threaded architecture by effectively increasing 
bandwidth per CPU core considerably. With regards, tornth [1] 
https://spec.torproject.org/tor-spec/preliminaries.html?highlight=cipher#ciphers[2]
 
https://www.intel.com/content/www/us/en/support/articles/000093843/technologies/intel-quickassist-technology-intel-qat.html
 

 
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