[GHC] #8733: I/O manager causes unnecessary syscalls in send/recv loops

[GHC]

#8733: I/O manager causes unnecessary syscalls in send/recv loops
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        Reporter:  tibbe                    |            Owner:
            Type:  bug                      |           Status:  new
        Priority:  normal                   |        Milestone:  7.10.1
       Component:  Runtime System           |          Version:  7.6.3
      Resolution:                           |         Keywords:
Operating System:  Unknown/Multiple         |     Architecture:
 Type of failure:  Runtime performance bug  |  Unknown/Multiple
       Test Case:                           |       Difficulty:  Unknown
        Blocking:                           |       Blocked By:
                                            |  Related Tickets:
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Comment (by tibbe):

 Replying to [comment:12 AndreasVoellmy]:
 > I would be interested to know what the source of the overhead is when
 making the recvfrom call that fails. I.e. is due to having more syscalls
 or from invoking the IO manager (Haskell-land) code to register the
 callback (requires taking an MVar, etc).

 Good question. I have a theory that the `MVar` overheads might be hurting
 us and integrating the I/O manager with the scheduler could allow us to
 get around that.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8733#comment:14>
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