Initializing array made of 33554432 64-bit words (256.00 MiB).
Source pages allocated with transparent hugepages: 100.0% (65536 pages, 100.0% flagged)
Legend:
  BandW: Implied bandwidth (assuming 64-byte cache line) in MB/s
  % Eff: Effectiness of this lane count compared to the prior, as a % of ideal
  Speedup: Speedup factor for this many lanes versus one lane
Applying Sattolo's algorithm... chain total: 33554432
Time to sum up the array (linear scan) 0.017 s (x 8 = 0.137 s), bandwidth = 14925.4 MB/s 
Size: 33554432 (262144.00 KiB, 256.00 MiB)
---------------------------------------------------------------------
- # of lanes --- time (s) ---- BandW -- ns/hit -- % Eff -- Speedup --
---------------------------------------------------------------------
           1     3.116681        657      92.9       0%        1.0
           2     1.572596       1302      46.9      99%        2.0
           3     1.078148       1900      32.1      94%        2.9
           4     0.812211       2522      24.2      99%        3.8
           5     0.652689       3138      19.5      98%        4.8
           6     0.545899       3752      16.3      98%        5.7
           7     0.469099       4366      14.0      98%        6.6
           8     0.413649       4951      12.3      95%        7.5
           9     0.369598       5541      11.0      96%        8.4
          10     0.335137       6111      10.0      93%        9.3
          11     0.307303       6664       9.2      91%       10.1
          12     0.284368       7202       8.5      90%       11.0
          13     0.267389       7659       8.0      78%       11.7
          14     0.252383       8115       7.5      79%       12.3
          15     0.237614       8619       7.1      88%       13.1
          16     0.226591       9038       6.8      74%       13.8
          17     0.222432       9207       6.6      31%       14.0
          18     0.219126       9346       6.5      27%       14.2
          19     0.217648       9410       6.5      13%       14.3
          20     0.216143       9475       6.4      14%       14.4
          21     0.214649       9541       6.4      15%       14.5
          22     0.214359       9554       6.4       3%       14.5
          23     0.213118       9610       6.4      13%       14.6
          24     0.215345       9510       6.4     -25%       14.5
          25     0.216098       9477       6.4      -9%       14.4
          26     0.216933       9441       6.5     -10%       14.4
          27     0.217314       9424       6.5      -5%       14.3
          28     0.218896       9356       6.5     -20%       14.2
          29     0.221121       9262       6.6     -29%       14.1
          30     0.219680       9323       6.5      20%       14.2
          31     0.221008       9267       6.6     -19%       14.1
          32     0.221733       9236       6.6     -11%       14.1
          33     0.222068       9222       6.6      -5%       14.0
          34     0.222116       9220       6.6      -1%       14.0
          35     0.224716       9114       6.7     -41%       13.9
          36     0.230729       8876       6.9     -96%       13.5
          37     0.233486       8771       7.0     -44%       13.3
          38     0.237242       8633       7.1     -61%       13.1
          39     0.241312       8487       7.2     -67%       12.9
          40     0.243429       8413       7.3     -35%       12.8
Maybe you have about 18 parallel paths? 
exit=0
