[GHC] #10693: Profile ghc -j with an eye for performance issues

[GHC]

#10693: Profile ghc -j with an eye for performance issues
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              Reporter:  bgamari     |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Compiler    |           Version:  7.10.1
              Keywords:              |  Operating System:  Unknown/Multiple
          Architecture:              |   Type of failure:  Compile-time
  Unknown/Multiple                   |  performance bug
             Test Case:              |        Blocked By:
              Blocking:              |   Related Tickets:
Differential Revisions:              |
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 `ghc -j` doesn't seem to scale as well as it could. Reports claim that
 even packages with embarasssingly parallel module structures (e.g.
 `highlighting-kate`) only scale out to three or so processors.

 Profiling a parallel build would be a useful first step to finding out
 why.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10693>
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