[tor-bugs] #26597 [Metrics/Onionperf]: Investigate and document additional overhead for first hop when not using guards

[Tor Bug Tracker & Wiki]

#26597: Investigate and document additional overhead for first hop when not using
guards
-----------------------------------+------------------------------
 Reporter:  irl                    |          Owner:  metrics-team
     Type:  defect                 |         Status:  needs_review
 Priority:  Medium                 |      Milestone:
Component:  Metrics/Onionperf      |        Version:
 Severity:  Normal                 |     Resolution:
 Keywords:  acute-2019-q1-planned  |  Actual Points:
Parent ID:                         |         Points:
 Reviewer:                         |        Sponsor:
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Changes (by karsten):

 * status:  assigned => needs_review
 * cc: metrics-team (added)


Comment:

 Suggested text (in bold) for the [https://metrics.torproject.org
 /onionperf-buildtimes.html graph page]:

 "This graph shows build times of circuits used for downloading static
 files of different sizes over Tor. '''The first hop build time is
 considerably higher in these measurements than subsequent hop build times
 or even first hop build times observed at common Tor clients. These
 measurements are performed using a newly selected guard for each
 measurement, whereas common Tor clients stay connected to a small number
 of guards which they use for all their circuits.''' The graph shows the
 range of measurements from first to third quartile, and highlights the
 median. The slowest and fastest quarter of measurements are omitted from
 the graph."

 If there's a way to say these with fewer words, please suggest that!

 We might not even need a more technical explanation for the
 [https://metrics.torproject.org/reproducible-metrics.html#performance
 reproducible metrics page]. After all, that page is there to explain how
 to reproduce our data, not to explain how Tor works.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/26597#comment:6>
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