[tor-bugs] #4486 [Analysis]: Research: should N23 actually help in practice?

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#4486: Research: should N23 actually help in practice?
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 Reporter:  arma                     |          Owner:       
     Type:  task                     |         Status:  new  
 Priority:  normal                   |      Milestone:       
Component:  Analysis                 |        Version:       
 Keywords:  performance flowcontrol  |         Parent:  #4506
   Points:                           |   Actualpoints:       
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Comment(by arma):

 Replying to [comment:7 robgjansen]:
 > Completed download counts may give us a sense of load on the network.
 > vanilla:
 > 24148 320KiB (web)
 > 74 5MiB (bulk)
 > n23:
 > 28767 320KiB (web)
 > 237 5MiB (bulk)

 So in this case the web downloads were a little bit slower, and the bulk
 downloads were a lot faster. And just as important, more of the downloads
 (especially bulk downloads) failed outright on the vanilla case. And most
 important of all, the code actually works.

 What do you count as a failed download? Does your downloader cut off the
 attempt after 50 or 80 seconds or something? Do we have any sense of
 whether these failed downloads got 0 bytes or 'most of the bytes' before
 failing?

 Mashael said, before seeing your results, "If N3Initial is small (50-70),
 it can throttle bulk downloaders and improve performance for browsers." So
 that's the clear next experiment: run the n23 side with "N3Initial 50".
 This means each circuit will have fewer cells in flight between relays
 (more accurately, sitting in the outbuf) at any given time.

 (I also just noticed that ewma is off unless explicitly turned on. We
 should continue leaving it off for now, but we should keep in mind that at
 some point in the future we'll want to compare with 'on'.)

 > I added the "window size hack" to my configuration, but ended up using
 the git version where that was presumably not needed. Would this cause any
 problems?

 It shouldn't.

 Thanks!

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/4486#comment:8>
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