[metrics-bugs] #24018 [Metrics/Statistics]: Automate measuring connection timeouts per exit

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#24018: Automate measuring connection timeouts per exit
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 Reporter:  arthuredelstein             |          Owner:  metrics-team
     Type:  project                     |         Status:  new
 Priority:  Medium                      |      Milestone:
Component:  Metrics/Statistics          |        Version:
 Severity:  Normal                      |     Resolution:
 Keywords:  tbb-performance, tbb-needs  |  Actual Points:
Parent ID:  #21394                      |         Points:
 Reviewer:                              |        Sponsor:
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Comment (by robgjansen):

 TLDR; OnionPerf does not currently do a great job of capturing DNS issues,
 but it could be made to do so.

 OnionPerf works by setting up a [https://github.com/shadow/shadow/wiki/3.3
 -TGen-Config traffic generator (TGen)] client and a server on the machine
 on which OnionPerf is run. OnionPerf makes the server accessible via an
 onion service (no DNS involved) as well as via the regular Internet. The
 client guesses an IP address of the machine on which it is running, and
 makes requests through Tor to that IP address.

 The reason for the above behavior is that it does not depend on the user
 running OnionPerf actually having a domain name registered for the host
 running OnionPerf. I thought that was a usability win, but I can see that
 this means we are missing some important aspect of Tor Browser
 performance.

 In principle, OnionPerf should be able to either pass IP address or domain
 name to Tgen. In the case that it passes a domain name, TGen will
 currently do the lookup itself rather than asking the socks proxy (Tor) to
 do it. In principle, TGen could ask the socks proxy (Tor) to do the lookup
 instead, and in fact the code already exists to do so in order to handle
 .onion fetches.

 Assuming that DNS errors would then be reported by Tor through the control
 port, it would be simple to have OnionPerf parse those errors and include
 them in the [https://metrics.torproject.org/collector.html#torperf output
 files desscribed here], or else in the raw json files that OnionPerf
 produces but Tor metrics does not yet publish.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24018#comment:9>
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