Script started on Thu Dec 15 17:57:54 1994 conx [emulator] pram -t -c -r 8 sum 1 2 3 4 5 6 7 8 CLOCK: 1321 36 conx [emulator] exit exit script done on Thu Dec 15 17:58:34 1994 The above is the result of 8(N) number with 8(N) processors. The following are the result using different number of N: N number and N processors N=1 ---> 70 cycles N=2 ---> 435 cycles differ from previous one : 365 N=4 ---> 852 cycles differ from previous one : 427 N=8 ---> 1321 cycles differ from previous one : 269 N=16 ---> 1842 cycles differ from previous one : 521 N=32 ---> 2415 cycles differ from previous one : 673 In this case, the differences are supposed to be the same (i.e. the algorithm is o(logN) ). We found it is increase slightly. The problem may be caused by the style of our program: limit := 1; for k := 1 to j do limit := 2*limit; end; // for This is for calculating 2^^j. The pm2 language does not support X^^Y function. Here may cause the side effect.