Opened 6 weeks ago

Last modified 10 days ago

#29773 needs_revision enhancement

Plot nearly worst-case circuit round-trip latencies to [public|onion] server

Reported by: karsten Owned by: metrics-team
Priority: Medium Milestone:
Component: Metrics/Website Version:
Severity: Normal Keywords: scalability
Cc: metrics-team Actual Points:
Parent ID: Points:
Reviewer: Sponsor:


We have been asked to add graphs on (nearly) worst-case performance of our OnionPerf measurements, in addition to the average-case performance graphs we already have. In particular, we were asked to plot latency and bandwidth numbers. This ticket is about latency numbers. It's based on team-internal discussions in Brussels and follow-up discussions. This ticket is related to #29772.

We already have graphs on circuit round-trip latencies. They show median and interquartile range, as do most of our OnionPerf graphs. Now we're asked to add graphs on (nearly) worst-case latencies, so 90th or 95th or 99th percentile.

I'm attaching two graphs showing 99th percentile latency. As you can see, these graphs are highly susceptible to outliers. I don't really know how to fix that. I mean, we could plot 95th percentile and hope there won't be outliers in those, but there's no guarantee for that. We could use a log scale, but that will make the graph so much harder to interpret. Hmm.

The coding and deployment effort for bringing this graph on the Tor Metrics website would be really small, because we'd simply have to extend an existing database view that returns 25th, 50th, and 75th percentile to also return 90th, 95th, or 99th percentile.

Child Tickets

Attachments (2)

onionperf-nwc-latencies-public.png (110.8 KB) - added by karsten 6 weeks ago.
onionperf-nwc-latencies-onion.png (102.5 KB) - added by karsten 6 weeks ago.

Download all attachments as: .zip

Change History (6)

Changed 6 weeks ago by karsten

Changed 6 weeks ago by karsten

comment:1 Changed 6 weeks ago by karsten

comment:2 Changed 3 weeks ago by karsten

Status: newneeds_review

comment:3 Changed 2 weeks ago by gaba

Keywords: scalability added

comment:4 Changed 10 days ago by irl

Status: needs_reviewneeds_revision
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