[GHC] #9221: (super!) linear slowdown of parallel builds on 40 core machine

[GHC]

#9221: (super!) linear slowdown of parallel builds on 40 core machine
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        Reporter:  carter            |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  high              |               Milestone:  7.12.1
       Component:  Compiler          |                 Version:  7.8.2
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:  #910              |  Differential Revisions:
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Comment (by simonpj):

 Alternatively, give each thread its own `NameCache`.  To do that, if one
 thread consumes a `ModIface` produced by another, it'd need to run over
 it, looking up all the `Names` to give them the `Unique` local to that
 thread.  Not so very different to having entirely separate processes
 communicating through files; and the latter is perhaps easier to think
 about.

 So, yes.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9221#comment:24>
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