[tor-bugs] #9574 [Tor]: Process ntor create cells before tap create cells?

[Tor Bug Tracker & Wiki]

#9574: Process ntor create cells before tap create cells?
-----------------------------+---------------------------------------
     Reporter:  arma         |      Owner:
         Type:  enhancement  |     Status:  needs_review
     Priority:  normal       |  Milestone:  Tor: 0.2.5.x-final
    Component:  Tor          |    Version:
   Resolution:               |   Keywords:  tor-relay, maybe-proposal
Actual Points:               |  Parent ID:
       Points:               |
-----------------------------+---------------------------------------

Comment (by mikeperry):

 Replying to [comment:21 arma]:
 > Replying to [comment:16 mikeperry]:
 > >      * Always answer at least N ntor requests for every 1 TAP request,
 if we have both.  (N=5? 10?)
 > >
 > > I think this one is my favorite for KISS reasons. We should have a
 consensus parameter for it too, of course. I kind of think we should kill
 TAP with fire and set this at like 100 though, and maybe even provide a -1
 or other magic value that always services ntor first.
 >
 > Added the consensus param in git commit 2d942f348. I went with 10 ntors
 per tap as the default, but I'd be amenable to having us set a bigger
 number like 100 in the consensus for now.
 >
 > I didn't implement the 'magic value' part. But values like 10000 should
 be plenty big.

 In this commit, you actually did #define MAX_NUM_NTORS_PER_TAP 1000. If
 ntor is only 10X faster than tap, this is still 10/1010 = 1% of the CPU
 wasted on TAP if we really want to kill it. If we optimize ntor further,
 to say 50X faster than TAP, this is 50/1050 or 4.7% CPU wasted on TAP,
 even after we want it to die.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9574#comment:24>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online