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) 0.009 s (x 8 = 0.068 s), bandwidth = 30036.4 MB/s 
Size: 33554432 (262144.00 KiB, 256.00 MiB)
---------------------------------------------------------------------
- # of lanes --- time (s) ---- BandW -- ns/hit -- % Eff -- Speedup --
---------------------------------------------------------------------
           1     3.792745        540     113.0       0%        1.0
           2     1.895509       1080      56.5     100%        2.0
           3     1.264221       1620      37.7     100%        3.0
           4     0.949381       2157      28.3     100%        4.0
           5     0.759189       2698      22.6     100%        5.0
           6     0.633447       3233      18.9      99%        6.0
           7     0.543996       3765      16.2      99%        7.0
           8     0.476553       4298      14.2      99%        8.0
           9     0.424400       4826      12.6      98%        8.9
          10     0.382846       5349      11.4      98%        9.9
          11     0.349902       5853      10.4      95%       10.8
          12     0.322272       6355       9.6      95%       11.8
          13     0.298812       6854       8.9      95%       12.7
          14     0.278202       7362       8.3      97%       13.6
          15     0.260390       7865       7.8      96%       14.6
          16     0.245601       8339       7.3      91%       15.4
          17     0.232568       8806       6.9      90%       16.3
          18     0.223993       9143       6.7      66%       16.9
          19     0.219653       9324       6.5      37%       17.3
          20     0.217524       9415       6.5      19%       17.4
          21     0.216861       9444       6.5       6%       17.5
          22     0.216312       9468       6.4       6%       17.5
          23     0.217047       9436       6.5      -8%       17.5
          24     0.215850       9488       6.4      13%       17.6
          25     0.215673       9496       6.4       2%       17.6
          26     0.215513       9503       6.4       2%       17.6
          27     0.215431       9507       6.4       1%       17.6
          28     0.216584       9456       6.5     -15%       17.5
          29     0.216663       9452       6.5      -1%       17.5
          30     0.216317       9468       6.4       5%       17.5
          31     0.216218       9472       6.4       1%       17.5
          32     0.216309       9468       6.4      -1%       17.5
          33     0.216110       9477       6.4       3%       17.6
          34     0.216368       9465       6.4      -4%       17.5
          35     0.216319       9468       6.4       1%       17.5
          36     0.216228       9471       6.4       2%       17.5
          37     0.216365       9465       6.4      -2%       17.5
          38     0.217176       9430       6.5     -14%       17.5
          39     0.215891       9486       6.4      23%       17.6
          40     0.216262       9470       6.4      -7%       17.5
Maybe you have about 19 parallel paths? 
exit=0
