-- 1 original
$ ghc -fforce-recomp -O2 --make 0.hs && /usr/bin/time ./0 +RTS -K100m -H100m && /usr/bin/time ./0 +RTS -K100m -H200m && /usr/bin/time ./0 +RTS -K100m -H400m
14.66user 0.32system 0:15.08elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
13.71user 0.39system 0:14.30elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
12.99user 0.54system 0:13.92elapsed 97%CPU (0avgtext+0avgdata 0maxresident)k

-- 2 strict accumulator
$ ghc -fforce-recomp -O2 --make 1.hs && /usr/bin/time ./1 +RTS -H100m && /usr/bin/time ./1 +RTS -H200m && /usr/bin/time ./1 +RTS -H400m
11.98user 0.14system 0:12.30elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
10.96user 0.35system 0:11.73elapsed 96%CPU (0avgtext+0avgdata 0maxresident)k
11.37user 0.49system 0:12.21elapsed 97%CPU (0avgtext+0avgdata 0maxresident)k

-- 3 refactor to do IO in IO
$ ghc -fforce-recomp -O2 --make 2.hs && /usr/bin/time ./2 +RTS -H100m && /usr/bin/time ./2 +RTS -H200m && /usr/bin/time ./2 +RTS -H400m
11.93user 0.17system 0:12.33elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
11.46user 0.34system 0:12.00elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
11.23user 0.45system 0:11.86elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k

-- 4a) pass StdGen around
$ ghc -fforce-recomp -O2 --make 3.hs && /usr/bin/time ./3 +RTS -H100m && /usr/bin/time ./3 +RTS -H200m && /usr/bin/time ./3 +RTS -H400m
10.38user 0.23system 0:10.64elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
10.34user 0.32system 0:10.69elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
9.94user 0.36system 0:10.33elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k

-- 4b) use System.Random.Mersenne
$ ghc -fforce-recomp -O2 --make 4.hs && /usr/bin/time ./4 +RTS -H100m && /usr/bin/time ./4 +RTS -H200m && /usr/bin/time ./4 +RTS -H400m
5.09user 0.05system 0:05.17elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
4.74user 0.22system 0:05.00elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
3.90user 0.38system 0:04.34elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k

-- 5) both 4a) and 4b)
$ ghc -fforce-recomp -O2 --make 5.hs && /usr/bin/time ./5 +RTS -H100m && /usr/bin/time ./5 +RTS -H200m && /usr/bin/time ./5 +RTS -H400m
2.59user 0.13system 0:02.74elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
1.50user 0.10system 0:01.60elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k
1.51user 0.08system 0:01.63elapsed 97%CPU (0avgtext+0avgdata 0maxresident)k

-- 6) unsafeRead and unsafeWrite
$ ghc -fforce-recomp -O2 --make 6.hs && /usr/bin/time ./6 +RTS -H100m && /usr/bin/time ./6 +RTS -H200m && /usr/bin/time ./6 +RTS -H400m
2.61user 0.11system 0:02.75elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
1.50user 0.10system 0:01.63elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
1.54user 0.06system 0:01.62elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k

-- 7) dons' version
$ ghc -fforce-recomp -O2 --make 7.hs && /usr/bin/time ./7 +RTS -H100m && /usr/bin/time ./7 +RTS -H200m && /usr/bin/time ./7 +RTS -H400m
1.34user 0.09system 0:01.45elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
1.37user 0.08system 0:01.47elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
1.36user 0.09system 0:01.47elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k

-- 8) 6) plus making L field strict
$ ghc -fforce-recomp -O2 --make 8.hs && /usr/bin/time ./8 +RTS -H100m && /usr/bin/time ./8 +RTS -H200m && /usr/bin/time ./8 +RTS -H400m
2.45user 0.09system 0:02.58elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
1.49user 0.09system 0:01.61elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
1.47user 0.09system 0:01.60elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k

$ ghc -funbox-strict-fields -fforce-recomp -O2 --make 8.hs && /usr/bin/time ./8 +RTS -H100m && /usr/bin/time ./8 +RTS -H200m && /usr/bin/time ./8 +RTS -H400m
1.44user 0.06system 0:01.52elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
1.44user 0.08system 0:01.54elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
1.47user 0.06system 0:01.54elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k