[tor-dev] Evaluating rendezvous circuit build up CPU usage

[Valentin Franck]

Hello tor-devs,

I am currently working on a DoS mitigation system aiming to protect the
availability of onion services flooded with INTRO2 cells. My idea is
using a (Privacy Pass like) token based approach as suggested in
https://trac.torproject.org/projects/tor/ticket/31223#comment:6

For the evaluation of a first prototype I would like to compare CPU
usage times at the onion service when a) launching a rendezvous circuit
and b) validating a (potentially invalid) token. Is there an easy way,
to measure the CPU time a service spends for all operations triggered
when launching a new rendezvous circuit? Has somebody done that before?
Basically, I want to measure how much CPU time we save, if we do not
launch the rendezvous circuit. So far I have identified the following
functions: launch_rendezvous_point_circuit() and
service_rendezvous_circ_has_opened(). I understand that there is more
operations involved for building new circuits, since circuits are built
hop by hop. How can I  identify all relevant functions triggered after
launching the rendezvous circuit and include them in my measurements?

Once I have some reliable results I will provide you with more
information on what I am doing and how it is working so far.

Cheers
Valentin

This is my first post on this list :-). So have mercy, if I overlooked
resources to answer my question. Also, I am only beginning to
familiarize myself with the existing code base.