./Main +RTS -H512m -N -sstderr 
testing batcher sort sketch...
number of cnf clauses: 27871
converted poly with 27871 clauses
simplified to 9777 clauses
simplified to 4583 clauses

Finish Parse: 1.123947s
Finish Poly conversion: 0.242359s
Multiply small: 0.138535s
Multiply med-small: 3.932253s

  31,475,731,992 bytes allocated in the heap
     567,768,160 bytes copied during GC
      30,205,040 bytes maximum residency (10 sample(s))
       1,369,800 bytes maximum slop
             534 MB total memory in use (8 MB lost due to fragmentation)

  Generation 0:   123 collections,   122 parallel, 10.23s,  0.80s elapsed
  Generation 1:    10 collections,    10 parallel,  5.36s,  0.35s elapsed

  Parallel GC work balance: 4.73 (70932733 / 14985735, ideal 24)

                        MUT time (elapsed)       GC time  (elapsed)
  Task  0 (worker) :    3.45s    (  3.66s)       0.17s    (  0.01s)
  Task  1 (worker) :    3.97s    (  4.30s)       0.15s    (  0.01s)
  Task  2 (bound)  :    0.00s    (  4.30s)       7.77s    (  0.71s)
  Task  3 (worker) :    0.00s    (  4.30s)       0.00s    (  0.00s)
  Task  4 (worker) :    4.41s    (  4.30s)       0.18s    (  0.01s)
  Task  5 (worker) :    4.52s    (  4.30s)       0.11s    (  0.01s)
  Task  6 (worker) :    4.41s    (  4.30s)       0.00s    (  0.00s)
  Task  7 (worker) :    3.42s    (  4.30s)       1.00s    (  0.05s)
  Task  8 (worker) :    4.58s    (  4.30s)       0.00s    (  0.00s)
  Task  9 (worker) :    4.35s    (  4.30s)       0.27s    (  0.01s)
  Task 10 (worker) :    4.15s    (  4.30s)       0.25s    (  0.01s)
  Task 11 (worker) :    4.11s    (  4.30s)       0.31s    (  0.01s)
  Task 12 (worker) :    3.66s    (  4.30s)       0.31s    (  0.01s)
  Task 13 (worker) :    3.56s    (  4.30s)       0.84s    (  0.11s)
  Task 14 (worker) :    4.02s    (  4.30s)       0.49s    (  0.03s)
  Task 15 (worker) :    4.23s    (  4.30s)       0.36s    (  0.02s)
  Task 16 (worker) :    4.25s    (  4.30s)       0.35s    (  0.02s)
  Task 17 (worker) :    4.30s    (  4.30s)       0.16s    (  0.01s)
  Task 18 (worker) :    4.44s    (  4.30s)       0.13s    (  0.01s)
  Task 19 (worker) :    4.09s    (  4.30s)       0.51s    (  0.02s)
  Task 20 (worker) :    4.44s    (  4.30s)       0.18s    (  0.01s)
  Task 21 (worker) :    4.45s    (  4.30s)       0.15s    (  0.01s)
  Task 22 (worker) :    4.17s    (  4.30s)       0.17s    (  0.01s)
  Task 23 (worker) :    3.34s    (  4.30s)       0.76s    (  0.03s)
  Task 24 (worker) :    4.30s    (  4.30s)       0.12s    (  0.01s)
  Task 25 (worker) :    3.23s    (  4.30s)       0.85s    (  0.04s)

  SPARKS: 56502 (41084 converted, 2206 pruned)

  INIT  time    0.00s  (  0.00s elapsed)
  MUT   time   82.12s  (  4.30s elapsed)
  GC    time   15.59s  (  1.15s elapsed)
  EXIT  time    0.00s  (  0.00s elapsed)
  Total time   97.72s  (  5.45s elapsed)

  %GC time      16.0%  (21.0% elapsed)

  Alloc rate    383,242,810 bytes per MUT second

  Productivity  84.0% of total user, 1508.2% of total elapsed

gc_alloc_block_sync: 1373111
whitehole_spin: 0
gen[0].steps[0].sync_large_objects: 572
gen[0].steps[1].sync_large_objects: 418
gen[1].steps[0].sync_large_objects: 1710