[GHC] #9370: large blowup in memory usage and time when doing parallel build of xmlhtml package

[GHC]

#9370: large blowup in memory usage and time when doing parallel build of xmlhtml
package
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              Reporter:  carter      |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:  7.10.1
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:  parmake
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:  Compile-    |       Blocked By:
  time performance bug               |  Related Tickets:  #910 #9221
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by simonpj):

 That's bizarre.  I can't think why the the simplifier would do
 ''anything'' different with `-j1` vs `-j4`!

 I'm hard pressed even to see where to start.  Is it possible to determine
 when the log files start to differ?  They should be identical except for
 the uniques (which you can suppress with `-dsuppress-uniques`).

 Simon

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9370#comment:5>
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