[GHC] #13362: GHC first generation of GC to be as large as largest cache size by default

[GHC]

#13362: GHC first generation of GC to be as large as largest cache size by default
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        Reporter:  varosi            |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Runtime System    |              Version:  8.0.2
      Resolution:                    |             Keywords:  numa cache gc
                                     |  newcomers
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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Comment (by klapaucius):

 Stephen M Blackburn, Perry Cheng, Kathryn S McKinley - Myths and
 Realities: The Performance Impact of Garbage Collection p. 10
 5.4.5 Sizing the nursery

 "Figure 4(a) shows a small improvement with larger nurseries in mutator
 performance due to fewer L2 (Figure 4(e)) and TLB misses (Figure 4(f)).
 However, the difference in GC time dominates: smaller nurseries demand
 more frequent collection and thus a substantially higher load. We measured
 the fixed overhead of each collection <...> The garbage collection cost
 tapers off between 4MB and 8MB as the fixed collection costs become
 insignificant. These results debunk the myth that the nursery size should
 be matched to the L2 cache size (512KB on all three architectures)."

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13362#comment:6>
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