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

[Tor Bug Tracker & Wiki]

#22798: Windows relay is several times slower than Linux relay
-------------------------------------------------+-------------------------
 Reporter:  Vort                                 |          Owner:  (none)
     Type:  defect                               |         Status:
                                                 |  needs_review
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.3.3.x-final
Component:  Core Tor/Tor                         |        Version:  Tor:
                                                 |  0.2.9.11
 Severity:  Normal                               |     Resolution:
 Keywords:  tor-relay, performance, windows,     |  Actual Points:
  review-group-29                                |
Parent ID:                                       |         Points:  5
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------
Changes (by nickm):

 * cc: pastly, robgjansen, amj703 (added)


Comment:

 This looks plausible to me.  The function `update_send_buffer_size` should
 probably be static, and it definitely needs documentation.

 What do you mean above when you say "It breaks build"?

 You ask above:

 >    Is it is ok to compare result >= 0 or it should be result > 0?

 These are probably both okay.

 >    Maybe non-encrypted connection requires update_send_buffer_size call
 too?

 Yes, good idea.

 >    What is the good description for the function? Fix slow upload for
 Windows Vista and Windows 7 (bug #22798) would be enough?

 It should probably explain how it is doing that, and what exactly it is
 doing.

 >    Is this code compatible enough with C compilers?

 It looks like it shouldn't cause a problem outside Windows.  I don't see
 any likely issues here.


 Other things:

  * I'm adding the KIST people to the cc list, since I think they might
 have ideas about send-window stuff.
  * I see above that you have done work on measuring the performance
 impact, both for the syscalls and for the network performance.  Can you
 summarize the outcomes? I'm having a hard time understanding what the
 measurements actually say.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/22798#comment:128>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online