[tor-dev] Some information about Tor relays

Liu, Zhuotao zliu48 at illinois.edu
Fri Aug 26 04:46:45 UTC 2016

Thanks for that info, David. That seems valuable to me. :) 

However, I am a bit confused about the definition 

"cell-circuits-per-decile": Mean number of circuits that are included in any of the deciles, 
rounded up to the next integer. 

What is the exact meaning of 'decile'? Is it one tenth of a hour? Or something else? 

From: David Fifield [david at bamsoftware.com]
Sent: Thursday, August 25, 2016 23:26
To: Liu, Zhuotao
Cc: tor-dev at lists.torproject.org
Subject: Re: [tor-dev] Some information about Tor relays

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:
For example, see some of the files at

The "cell-circuits-per-decile" lines might be interesting to you.
    "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:

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