[tor-bugs] #22798 [Core Tor/Tor]: Windows relay is several times slower than Linux relay

Mon Jul 3 05:27:37 UTC 2017

#22798: Windows relay is several times slower than Linux relay
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     Reporter:  Vort     |      Owner:
         Type:  defect   |     Status:  new
     Priority:  Medium   |  Milestone:  Tor: unspecified
    Component:  Core     |    Version:  Tor: 0.2.9.11
  Tor/Tor                |
     Severity:  Major    |   Keywords:  tor-relay network performance win32
Actual Points:           |  Parent ID:
       Points:           |   Reviewer:
      Sponsor:           |
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 I have launched two relays: first one in native mode on Windows, second
 one in virtual machine on Linux.

 Then measured their bandwidth using three-hop circuit: refEntry, myRelay,
 refExit
 refEntry is
 [[https://atlas.torproject.org/#details/13B2354C74CCE29815B4E1F692F2F0E86C7F13DD|13B2354C74CCE29815B4E1F692F2F0E86C7F13DD]]
 refExit is
 [[https://atlas.torproject.org/#details/07C05ED4825F51D5BE4CDBBAA80BFA484132A2F5|07C05ED4825F51D5BE4CDBBAA80BFA484132A2F5]]

 Windows version of Tor was able to provide 51 KiB/s.
 Linux version - 163 KiB/s, which is three times higher.

 But this was my measurements.
 BwAuth ratings for this relays are far more different:
 Windows one have weight = 18 (19/13/22/18).
 Linux one got weight = 1030 (293/1030/1460).

 Which leads to actual traffic rising from 1 KiB/s to ~500 KiB/s.

 I can keep relay in virtual machine for a while, but it would be much
 better if Windows version gets fixed.

 Here are the versions of software used in tests:
 OS: Windows 7 SP1 x64 (host)
 OS: Ubuntu 16.04 x64 (guest)
 VM: VirtualBox 5.1.22
 Tor: 0.2.9.11 (Linux)
 Tor: 0.2.9.11, 0.3.0.8 (Windows)

 Also I have obtained TCP packets dump from relay's network interface:
 https://yadi.sk/d/2XrUmz3A3KgqZb

 Packets 1-1584 are slow transfer (Windows relay).
 Packets 1585-8659 are fast transfer (Linux VM relay).

 I can made additional tests and provide additional information if needed.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/22798>
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