[GHC] #15153: GHC uses O_NONBLOCK on regular files, which has no effect, and blocks the runtime

[GHC]

#15153: GHC uses O_NONBLOCK on regular files, which has no effect, and blocks the
runtime
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        Reporter:  nh2               |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Runtime System    |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by nh2):

 Also funny but perhaps not too surprising:

 If in my code, you replace `forkIO` by e.g. `forkOn 2`, then
 nondeterministically, sometimes the program hangs and sometimes it works
 with `+RTS -N2`.

 The higher you set `-N`, the more likely it is to work.

 If you put both the putStrLn loop and the readFile into `forkOn 0` and
 `forkOn 1` each, and run with `+RTS -N3`, then it always works as
 expected.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15153#comment:2>
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