test +RTS -stest2ps.stat 
1,361,661,680 bytes allocated in the heap
 93,647,172 bytes copied during GC (scavenged)
 80,446,868 bytes copied during GC (not scavenged)
 35,585,988 bytes maximum residency (7 sample(s))

       2616 collections in generation 0 (  0.79s)
          7 collections in generation 1 (  0.83s)

         69 Mb total memory in use

  INIT  time    0.02s  (  0.00s elapsed)
  MUT   time    3.64s  (  3.59s elapsed)
  GC    time    1.62s  (  1.58s elapsed)
  EXIT  time    0.00s  (  0.00s elapsed)
  Total time    5.28s  (  5.17s elapsed)

  %GC time      30.7%  (30.6% elapsed)

  Alloc rate    372,445,754 bytes per MUT second

  Productivity  68.9% of total user, 70.4% of total elapsed