[tor-bugs] #4086 [Analysis]: Compare performance of TokenBucketRefillInterval params in simulated network

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#4086: Compare performance of TokenBucketRefillInterval params in simulated
network
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 Reporter:  arma                     |          Owner:       
     Type:  task                     |         Status:  new  
 Priority:  normal                   |      Milestone:       
Component:  Analysis                 |        Version:       
 Keywords:  performance flowcontrol  |         Parent:  #4465
   Points:                           |   Actualpoints:       
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Changes (by robgjansen):

 * cc: jansen@… (removed)
 * cc: robgjansen (added)


Comment:

 Replying to [comment:10 arma]:

 > Replying to [comment:6 robgjansen]:
 >
 >
 > > 50 servers, 50 relays, 475 web clients, 25 bulk clients. Relay
 bandwidths are taken from real consensus and rate limits from real server
 descriptors
 > >
 > >
 >
 > If you take relay bandwidths from the server descriptors and not from
 the consensus, do the results change? I would guess you'll have less
 overall capacity in the network, so the effect of EWMA should be even more
 pronounced. Though then again, since you're rate limiting to the values in
 the descriptor already, the only difference would be relays that have lots
 of extra capacity but haven't changed the rate limiting from its default,
 and those are probably rare.

 I'm not sure why you think there will be much less capacity. I've attached
 [https://trac.torproject.org/projects/tor/attachment/ticket/4086/consensus_vs_observed.pdf
 a CDF showing the distribution of consensus bandwidth weights vs relay-
 reported observed bandwidth]. Turns out the difference between the CDFs
 (absolute value of the difference in the integral over the range
 [0,infty]) is less than 1000 KiB/s.

 >
 >
 >
 > > it would appear Tor should be scheduling with RR and refilling every
 10-100 ms (maybe 50?).
 > >
 > >
 >
 > Is it easy to do up a graph with 50ms refill rates, to see if it's more
 like 10 or more like 100? That would also give us a sense of how much
 variation there is in simulation outcome.

 Yes.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/4086#comment:15>
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