[tor-dev] Some information about Tor relays

[David Fifield]

On Fri, Aug 26, 2016 at 01:42:38AM +0000, Liu, Zhuotao wrote:
> This is Sky from University of Illinois. Currently we are working on research
> project related with Tor. 
> 
> To help us to better design and evaluation our proposal, we need some
> information about the Tor relays that is currently unavailable from the Atlas.
> Thus, if someone who operates Tor relays could provide us such information,
> your help will be greatly appreciated. :) 
> 
> We hope to have an estimate about computation capacity of Tor relays. For
> instance, how many circuits a relay can maintain when its CPU is driven to
> about 100%? On average, how many circuits are maintained by a busy guard and
> what the CPU utilization is. These kinds of information would be really
> helpful. 

I don't know about CPU usage, but as for circuits, I think you can get
them from @extra-info and @bridge-extra-info descriptors:
	https://collector.torproject.org/#type-extra-info
	https://collector.torproject.org/#type-bridge-extra-info
For example, see some of the files at
	https://collector.torproject.org/recent/relay-descriptors/extra-infos/

The "cell-circuits-per-decile" lines might be interesting to you.
https://spec.torproject.org/dir-spec:
    "cell-circuits-per-decile" num NL
        Mean number of circuits that are included in any of the deciles,
        rounded up to the next integer.

For parsing the descriptor files, you can use Stem:
	https://stem.torproject.org/_modules/stem/descriptor/extrainfo_descriptor.html