[tor-relays] How to reduce tor CPU load on a single bridge?

David Fifield david at bamsoftware.com
Tue Feb 8 17:02:28 UTC 2022


The load-balanced Snowflake bridge is running in production since
2022-01-31. Thanks Roger, Gary, Roman for your input.

Hopefully reproducible installation instructions:
	https://gitlab.torproject.org/tpo/anti-censorship/team/-/wikis/Survival-Guides/Snowflake-Bridge-Installation-Guide?version_id=6de6facbb0fd047de978a561213c59224511445f
Observations since:
	https://bugs.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/40095#note_2774428

Metrics graphs are currently confused by multiple instances of tor
uploading descriptors under the same fingerprint. Particularly in the
interval between 2022-01-25 and 2022-02-03, when a production bridge and
staging bridge were running in parallel, with four instances being used
and another four being mostly unused.
	https://metrics.torproject.org/rs.html#details/5481936581E23D2D178105D44DB6915AB06BFB7F
	https://metrics.torproject.org/userstats-bridge-transport.html?start=2021-11-10&end=2022-02-08&transport=snowflake
Since 2022-02-03, it appears that Metrics is showing only one of the
four running instances per day. Because all four instances are about
equally used (as if load balanced, go figure), the values on the graph
are 1/4 what they should be. The reported bandwidth of 5 MB/s is
actually 20 MB/s, and the 2500 clients are actually 10000. All the
necessary data are present in Collector, it's just a question of data
processing. I opened an issue for the Metrics graphs, where you can also
see some manually made graphs that are closer to the true values.
	https://bugs.torproject.org/tpo/network-health/metrics/onionoo/40022

I started a thread on tor-dev about the issues of onion key rotation and
ExtORPort authentication.
	https://lists.torproject.org/pipermail/tor-dev/2022-February/thread.html


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