[GHC] #10652: Better cache performance in Array#

[GHC]

#10652: Better cache performance in Array#
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        Reporter:  MikeIzbicki       |                   Owner:
            Type:  feature request   |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
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Comment (by carter):

 Mike: have you looked at how the gc arranges values only reachable via a
 boxed array?
 I guess one problem I can think of off hand is that your primops get
 tricky when a value is shared across Multiple boxed arrays!
 A valid and interesting idea would be to just make sure that the gc places
 unshared values reachable only via a boxed array continuously when doing a
 copying gc.  I should try to look into this myself.
 Relatedly: bob Harper et all did prove a few years ago that certain gc
 strategies do result in cache optimal memory layouts.  But I don't know if
 ghc does a traversal order that maps to their specific proof.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10652#comment:3>
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