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authorEelco Dolstra <eelco.dolstra@logicblox.com>2012-08-13T05·05-0400
committerEelco Dolstra <eelco.dolstra@logicblox.com>2012-08-13T05·05-0400
commitb9e5b908ed29bfb6cd82837f9f57293c1f63e999 (patch)
treebf83e68c67ec3e37720634c6ccca1d53594a3346 /src/libexpr/eval.cc
parent4ccd48ce2478cbe1263605838969f89d5b745f0a (diff)
Provide an efficient implementation of ‘elem’
The one in Nixpkgs is O(n^2), this one is O(n).  Big reduction in the
number of list allocations.

Statistics before (on a NixOS system config):

  time elapsed: 1.17982
  size of a value: 24
  environments allocated: 1543334 (39624560 bytes)
  list elements: 9612638 (76901104 bytes)
  list concatenations: 37434
  values allocated: 1854933 (44518392 bytes)
  attribute sets allocated: 392040
  right-biased unions: 186334
  values copied in right-biased unions: 591137
  symbols in symbol table: 18272
  number of thunks: 1392467
  number of thunks avoided: 1507311
  number of attr lookups: 430801
  number of primop calls: 691600
  number of function calls: 1492502

Statistics after:

  time elapsed: 1.08683
  size of a value: 24
  environments allocated: 1384376 (35809568 bytes)
  list elements: 6946783 (55574264 bytes)
  list concatenations: 37434
  values allocated: 1760440 (42250560 bytes)
  attribute sets allocated: 392040
  right-biased unions: 186334
  values copied in right-biased unions: 591137
  symbols in symbol table: 18273
  number of thunks: 1297673
  number of thunks avoided: 1380759
  number of attr lookups: 430802
  number of primop calls: 628912
  number of function calls: 1333544
Diffstat (limited to 'src/libexpr/eval.cc')
0 files changed, 0 insertions, 0 deletions