[tor-relays] Consensus Weight calculation

[Vort]

Finally, I have made my test program and found that I was
  wrong about two things:

1. Low weight relays (< 30) rarely give fast speed (> 150 KiB/s) on
  two-hop circuits. With three hops, fast speed even more rare thing.

2. Windows version of Tor really have some problems.


I don't quite understand the factors, which have influence on
  circuit speed, but, at least, I have found how it is possible to
  obtain the low bandwidth estimate for my relay.

I have selected two entry nodes and two exit nodes:
refEntry1 D665C959571041972EA8C0DD77559EF5579BA112
refEntry2 13B2354C74CCE29815B4E1F692F2F0E86C7F13DD
refExit1  5CECC5C30ACC4B3DE462792323967087CC53D947
refExit2  07C05ED4825F51D5BE4CDBBAA80BFA484132A2F5

Then launched four circuits:
refEntry1, myNode, refExit1
refEntry1, myNode, refExit2
refEntry2, myNode, refExit1
refEntry2, myNode, refExit2

And measured their bandwidth:
1. 117 KiB/s
2. 122 KiB/s
3. 59  KiB/s
4. 51  KiB/s

That was pretty strange.
Previous tests with speedtest.net showed that 500-1000 KiB/s
  speeds are not a problem for my connection.

Next idea was to measure the neighbor relay (from the same city and ISP).
And this resulted in following speeds:
1. 356 KiB/s
2. 392 KiB/s
3. 375 KiB/s
4. 271 KiB/s

Not too fast, but definitely better than result for my relay.

So one of the limiting factors is located somewhere on my computer.
Connection count is fine, RAM and CPU are also good enough.

The only difference left is operating system.

It is possible for me to boot from USB stick with some Linux.
But first I have decided to make a test with virtual machine.

Port forwarding was set, Ubuntu and new Tor relay are
  launched and here is the result:
1. 452 KiB/s
2. 375 KiB/s
3. 141 KiB/s
4. 163 KiB/s

Usually adding a virtual machine leads to worse results.
But not this time.

So the next question is:
How Linux version inside Windows can perform three times
  better than Windows version alone?

And what is the real limit for my configuration?
Even if 100 KiB/s speed changes to 300 KiB/s, this will be still
  far from 1 MiB/s, 5 MiB/s, 10 MiB/s, which are possible with
  my connection.


-- Vort