Opened 7 months ago

Closed 6 months ago

#34215 closed defect (fixed)

Harmonize TTFB/TTLB definitions with Tor Metrics plots

Reported by: karsten Owned by: karsten
Priority: Medium Milestone:
Component: Metrics/Onionperf Version:
Severity: Normal Keywords:
Cc: metrics-team, acute, phw Actual Points: 0.1
Parent ID: #33327 Points:
Reviewer: Sponsor: Sponsor59


Right now, OnionPerf plots 'command' to 'first_byte', whereas Tor Metrics plots 'start' to 'first_byte' (as found in #33258). We should harmonize these definitions, which likely means using what we have been using for Tor Metrics plots for the past decade.

Child Tickets

Change History (4)

comment:1 Changed 6 months ago by karsten

Parent ID: #33327

comment:2 Changed 6 months ago by karsten

Owner: changed from metrics-team to karsten
Status: newaccepted

Picking this up now.

comment:3 Changed 6 months ago by karsten

Status: acceptedneeds_review

The first question here is how we want to define TTFB/TTLB:

  • Right now, OnionPerf considers the time between the tgen client sending the HTTP request to the tgen server and receiving the first/last byte of the HTTP response back as TTFB/TTLB. This excludes all the magic happening inside the tor client to provide a circuit and attach a stream to it. In some cases this is pretty fast, for example, when it can reuse a pre-built circuit to connect via an exit to its own tgen server. In other cases this can take a while, for example, when it needs to do the entire hiddenonion service connection establishment dance.
  • The Time to download files over Tor graph on the Tor Metrics website measures TTLB as the time between the tgen client starting a measurement and receiving the last byte of the HTTP response from the tgen server. This includes all the magic as written above.

I'd argue that we do care about measuring what's going on in tor, so we should switch OnionPerf to the definitions used on the Tor Metrics website graph. Commit a836f87 in my task-34215 branch contains the trivial patch. Comments welcome! I'll also bring this up for discussion at our next weekly meeting.

comment:4 Changed 6 months ago by karsten

Actual Points: 0.1
Resolution: fixed
Status: needs_reviewclosed

We agreed at today's team meeting that this is a good change. Rebased and merged to master. Closing.

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