[GHC] #14964: performance regressions from 8.0.2 to 8.4.1

[GHC]

#14964: performance regressions from 8.0.2 to 8.4.1
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        Reporter:  elaforge          |                Owner:  (none)
            Type:  task              |               Status:  infoneeded
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.4.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         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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Changes (by simonpj):

 * priority:  high => normal


Comment:

 The productivity number is down sharply, and consistently so, which
 translates directly into longer run times.  Somehow, although residency
 (well max-memory-in-use at least) is not increasing, GC time is greatly
 increased.

 It'd be really good to characterise this some more.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14964#comment:7>
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