[tahoe-dev] [tahoe-lafs] #1170: new-downloader performs badly when downloading a lot of data from a file

[tahoe-lafs]

#1170: new-downloader performs badly when downloading a lot of data from a file
------------------------------+---------------------------------------------
     Reporter:  zooko         |       Owner:                                           
         Type:  defect        |      Status:  new                                      
     Priority:  critical      |   Milestone:  1.8.0                                    
    Component:  code-network  |     Version:  1.8β                                     
   Resolution:                |    Keywords:  immutable download performance regression
Launchpad Bug:                |  
------------------------------+---------------------------------------------

Comment (by zooko):

 Well the good news is that comment:54 fixes the problem that downloads go
 slower the bigger they are (as expected). The bad news is that even with
 comment:54 Tahoe-LAFS v1.8.0c2 is substantially slower than v1.7.1 for
 large files:

 ||= run =||= version =||= downloaded =||= download KBps =||= flags =||
 || [comment:59 116] || 1.8.0c2 || 314 MB ||   154 ||
 [attachment:spans.py.diff spans.py.diff] + comment:54 ||

 {{{
 MUSI Zooko-Ofsimplegeos-MacBook-Pro:~/Desktop$ echo this is run 115 tahoe-
 lafs v1.8.0c2+comment:54 ; time curl
 http://localhost:3456/file/URI%3ACHK%3A4klgnafrwsm2nx3bqy24ygac5a%3Acrz7nhthi4bevzrug6xwgif2vhiacp7wk2cfmjutoz2ns3w45qza%3A3%3A10%3A1490710513/@@named
 =/bbb-360p24.i420.lossless.drc.ogg.fixed.ogg%2Bbbb-24fps.flac.via-
 ffmpeg.ogg  > bbb.ogg
 this is run 115 tahoe-lafs v1.8.0c2+comment:54
   % Total    % Received % Xferd  Average Speed   Time    Time     Time
 Current
                                  Dload  Upload   Total   Spent    Left
 Speed
  21 1421M   21  300M    0     0   154k      0  2:37:11  0:33:16  2:03:55
 160k^C

 real    33m16.529s
 user    0m0.203s
 sys     0m1.507s
 }}}

 I'm going to start another run with v1.8.0c2, this time with the cProfile
 tool running, and go to sleep.

-- 
Ticket URL: <http://tahoe-lafs.org/trac/tahoe-lafs/ticket/1170#comment:59>
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