$ sudo ./script.sh
always [madvise] never
mode:  always
[always] madvise never
Initializing array made of 33554432 64-bit words.
Applying Sattolo's algorithm.
Surgery on the long cycle.
Verifying the neighboring distance...
mindist = 335544 vs 335544
Time to sum up the array (linear scan) 0.010 s (x 8 = 0.080 s), bandwidth = 25600.0 MB/s
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
---------------------------------------------------------------------
- # of lanes --- time (s) ---- BandW -- ns/hit -- % Eff -- Speedup --
---------------------------------------------------------------------
           1     3.720000        551     110.9       0%        1.0
           2     1.820000       1125      54.2     102%        2.0
           3     1.130000       1812      33.7     114%        3.3
           4     0.850000       2409      25.3      99%        4.4
           5     0.680000       3012      20.3     100%        5.5
           6     0.570000       3593      17.0      97%        6.5
           7     0.490000       4180      14.6      98%        7.6
           8     0.430000       4763      12.8      98%        8.7
           9     0.380000       5389      11.3     105%        9.8
          10     0.340000       6024      10.1     105%       10.9
          11     0.320000       6400       9.5      65%       11.6
          12     0.290000       7062       8.6     112%       12.8
          13     0.270000       7585       8.0      90%       13.8
          14     0.250000       8192       7.5     104%       14.9
          15     0.240000       8533       7.2      60%       15.5
          16     0.230000       8904       6.9      67%       16.2
          17     0.220000       9309       6.6      74%       16.9
          18     0.210000       9752       6.3      82%       17.7
          19     0.200000      10240       6.0      90%       18.6
          20     0.190000      10779       5.7     100%       19.6
          21     0.190000      10779       5.7       0%       19.6
          22     0.180000      11378       5.4     116%       20.7
          23     0.180000      11378       5.4       0%       20.7
          24     0.180000      11378       5.4       0%       20.7
          25     0.170000      12047       5.1     139%       21.9
          26     0.170000      12047       5.1       0%       21.9
          27     0.170000      12047       5.1       0%       21.9
          28     0.170000      12047       5.1       0%       21.9
          29     0.170000      12047       5.1       0%       21.9
          30     0.170000      12047       5.1       0%       21.9
          31     0.170000      12047       5.1       0%       21.9
          32     0.170000      12047       5.1       0%       21.9
          33     0.170000      12047       5.1       0%       21.9
          34     0.170000      12047       5.1       0%       21.9
          35     0.170000      12047       5.1       0%       21.9
          36     0.170000      12047       5.1       0%       21.9
          37     0.170000      12047       5.1       0%       21.9
          38     0.170000      12047       5.1       0%       21.9
          39     0.170000      12047       5.1       0%       21.9
          40     0.170000      12047       5.1       0%       21.9
          41     0.170000      12047       5.1       0%       21.9
          42     0.170000      12047       5.1       0%       21.9
          43     0.170000      12047       5.1       0%       21.9
          44     0.170000      12047       5.1       0%       21.9
          45     0.170000      12047       5.1       0%       21.9
          46     0.170000      12047       5.1       0%       21.9
          47     0.170000      12047       5.1       0%       21.9
          48     0.170000      12047       5.1       0%       21.9
          49     0.170000      12047       5.1       0%       21.9
          50     0.170000      12047       5.1       0%       21.9
          51     0.170000      12047       5.1       0%       21.9
          52     0.170000      12047       5.1       0%       21.9
          53     0.170000      12047       5.1       0%       21.9
          54     0.170000      12047       5.1       0%       21.9
          55     0.170000      12047       5.1       0%       21.9
          56     0.170000      12047       5.1       0%       21.9
          57     0.180000      11378       5.4    -335%       20.7
          58     0.170000      12047       5.1     322%       21.9
          59     0.180000      11378       5.4    -347%       20.7
          60     0.180000      11378       5.4       0%       20.7
          61     0.180000      11378       5.4       0%       20.7
          62     0.170000      12047       5.1     344%       21.9
          63     0.180000      11378       5.4    -371%       20.7
          64     0.180000      11378       5.4       0%       20.7
          65     0.180000      11378       5.4       0%       20.7
          66     0.180000      11378       5.4       0%       20.7
          67     0.170000      12047       5.1     372%       21.9
          68     0.180000      11378       5.4    -400%       20.7
          69     0.180000      11378       5.4       0%       20.7
          70     0.180000      11378       5.4       0%       20.7
          71     0.180000      11378       5.4       0%       20.7
          72     0.180000      11378       5.4       0%       20.7
          73     0.170000      12047       5.1     406%       21.9
          74     0.180000      11378       5.4    -435%       20.7
          75     0.180000      11378       5.4       0%       20.7
          76     0.170000      12047       5.1     422%       21.9
          77     0.180000      11378       5.4    -453%       20.7
          78     0.180000      11378       5.4       0%       20.7
          79     0.170000      12047       5.1     439%       21.9
          80     0.180000      11378       5.4    -471%       20.7
          81     0.170000      12047       5.1     450%       21.9
          82     0.180000      11378       5.4    -482%       20.7
          83     0.170000      12047       5.1     461%       21.9
          84     0.180000      11378       5.4    -494%       20.7
          85     0.170000      12047       5.1     472%       21.9
          86     0.180000      11378       5.4    -506%       20.7
          87     0.170000      12047       5.1     483%       21.9
          88     0.180000      11378       5.4    -518%       20.7
          89     0.170000      12047       5.1     494%       21.9
          90     0.180000      11378       5.4    -529%       20.7
          91     0.170000      12047       5.1     506%       21.9
          92     0.180000      11378       5.4    -541%       20.7
          93     0.170000      12047       5.1     517%       21.9
          94     0.180000      11378       5.4    -553%       20.7
          95     0.170000      12047       5.1     528%       21.9
          96     0.180000      11378       5.4    -565%       20.7
          97     0.180000      11378       5.4       0%       20.7
          98     0.170000      12047       5.1     544%       21.9
          99     0.180000      11378       5.4    -582%       20.7
Maybe you have about 20 parallel paths?
mode:  never
always madvise [never]
Initializing array made of 33554432 64-bit words.
Applying Sattolo's algorithm.
Surgery on the long cycle.
Verifying the neighboring distance...
mindist = 335544 vs 335544
Time to sum up the array (linear scan) 0.010 s (x 8 = 0.080 s), bandwidth = 25600.0 MB/s
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
---------------------------------------------------------------------
- # of lanes --- time (s) ---- BandW -- ns/hit -- % Eff -- Speedup --
---------------------------------------------------------------------
           1     4.510000        454     134.4       0%        1.0
           2     2.220000        923      66.2     102%        2.0
           3     1.410000       1452      42.0     109%        3.2
           4     1.050000       1950      31.3     102%        4.3
           5     0.850000       2409      25.3      95%        5.3
           6     0.710000       2885      21.2      99%        6.4
           7     0.610000       3357      18.2      99%        7.4
           8     0.540000       3793      16.1      92%        8.4
           9     0.500000       4096      14.9      67%        9.0
          10     0.480000       4267      14.3      40%        9.4
          11     0.470000       4357      14.0      23%        9.6
          12     0.470000       4357      14.0       0%        9.6
          13     0.470000       4357      14.0       0%        9.6
          14     0.470000       4357      14.0       0%        9.6
          15     0.470000       4357      14.0       0%        9.6
          16     0.480000       4267      14.3     -34%        9.4
          17     0.480000       4267      14.3       0%        9.4
          18     0.480000       4267      14.3       0%        9.4
          19     0.480000       4267      14.3       0%        9.4
          20     0.480000       4267      14.3       0%        9.4
          21     0.480000       4267      14.3       0%        9.4
          22     0.480000       4267      14.3       0%        9.4
          23     0.480000       4267      14.3       0%        9.4
          24     0.480000       4267      14.3       0%        9.4
          25     0.480000       4267      14.3       0%        9.4
          26     0.480000       4267      14.3       0%        9.4
          27     0.480000       4267      14.3       0%        9.4
          28     0.480000       4267      14.3       0%        9.4
          29     0.480000       4267      14.3       0%        9.4
          30     0.480000       4267      14.3       0%        9.4
          31     0.480000       4267      14.3       0%        9.4
          32     0.480000       4267      14.3       0%        9.4
          33     0.480000       4267      14.3       0%        9.4
          34     0.480000       4267      14.3       0%        9.4
          35     0.480000       4267      14.3       0%        9.4
          36     0.480000       4267      14.3       0%        9.4
          37     0.480000       4267      14.3       0%        9.4
          38     0.480000       4267      14.3       0%        9.4
          39     0.480000       4267      14.3       0%        9.4
          40     0.480000       4267      14.3       0%        9.4
          41     0.480000       4267      14.3       0%        9.4
          42     0.480000       4267      14.3       0%        9.4
          43     0.480000       4267      14.3       0%        9.4
          44     0.480000       4267      14.3       0%        9.4
          45     0.480000       4267      14.3       0%        9.4
          46     0.480000       4267      14.3       0%        9.4
          47     0.480000       4267      14.3       0%        9.4
          48     0.480000       4267      14.3       0%        9.4
          49     0.480000       4267      14.3       0%        9.4
          50     0.480000       4267      14.3       0%        9.4
          51     0.480000       4267      14.3       0%        9.4
          52     0.480000       4267      14.3       0%        9.4
          53     0.480000       4267      14.3       0%        9.4
          54     0.480000       4267      14.3       0%        9.4
          55     0.480000       4267      14.3       0%        9.4
          56     0.480000       4267      14.3       0%        9.4
          57     0.480000       4267      14.3       0%        9.4
          58     0.480000       4267      14.3       0%        9.4
          59     0.480000       4267      14.3       0%        9.4
          60     0.480000       4267      14.3       0%        9.4
          61     0.480000       4267      14.3       0%        9.4
          62     0.480000       4267      14.3       0%        9.4
          63     0.480000       4267      14.3       0%        9.4
          64     0.480000       4267      14.3       0%        9.4
          65     0.480000       4267      14.3       0%        9.4
          66     0.480000       4267      14.3       0%        9.4
          67     0.480000       4267      14.3       0%        9.4
          68     0.480000       4267      14.3       0%        9.4
          69     0.480000       4267      14.3       0%        9.4
          70     0.480000       4267      14.3       0%        9.4
          71     0.480000       4267      14.3       0%        9.4
          72     0.480000       4267      14.3       0%        9.4
          73     0.480000       4267      14.3       0%        9.4
          74     0.480000       4267      14.3       0%        9.4
          75     0.480000       4267      14.3       0%        9.4
          76     0.480000       4267      14.3       0%        9.4
          77     0.480000       4267      14.3       0%        9.4
          78     0.480000       4267      14.3       0%        9.4
          79     0.480000       4267      14.3       0%        9.4
          80     0.480000       4267      14.3       0%        9.4
          81     0.480000       4267      14.3       0%        9.4
          82     0.480000       4267      14.3       0%        9.4
