Re: Is tor being slowed up to ~20ms per hop by TCP delayed ACK?

[phobos@xxxxxxxxxx]

On Sun, Jul 20, 2008 at 10:52:44AM -0700, adam_richter2004@xxxxxxxxx wrote 2.5K bytes in 53 lines about:
: tor-0.2.1.2-alpha or libevent-1.3e.  Have I missed some other library
: that tor is using to avoid unnecessary Nagle delays?
: 
: 	I am thinking about modifying tor so that, _when it has
: nothing else to do_, it will set and clear TCP_NODELAY on any sockets
: that the outgoing data is flushed.  Outgoing TCP data would continue
: to be coalesced when tor has more input pending from any connection.
: The pushes would only be done if tor is about to go to sleep in
: select() and has transmitted unpushed data pending.
: 
: 	Am I overlooking something?  Has anyone else looked into this?

Others have raised the possibility that tcp overhead and delays are the
leading cause of tor slowness, not encryption overhead.  I don't know
that anyone has done a rigorous analysis of tcp congestion/nagle/delays
over Tor.  

-- 
Andrew