sub myRand{ unpack('Q', pack'C8', map rand()*256, 1 ..8) / 2**64 }

undef%hash; say time; ++$hash{ int( 50000*myRand() ) } while keys %hash < 50000; say time;;
1376006416.04139
1376006418.40272

say ~~keys %hash;;
50000

print sum values %hash;;
543283