program from RT #129779 changed to run with n from 2 through 16

gistfile1.txt

use v6;

my $r = 2_000_000;

say "Counting to $r";

my ($start, $setup, $stop);
$start = now;
{
     my ($i, $j);
     $j = $r;
     loop ($i = 0; $i < $j; $i++) { }
}
$stop = now;

say "Non-promise iteration: {$stop - $start}";

my @promises;
$start = now;
@promises.push(start {
     my ($i, $j);
     $j = $r;
     loop ($i = 0; $i < $j; $i++) { }
});
$setup = now;
await Promise.allof(@promises);
$stop = now;

say "One iteration: {$stop - $start} (setup: {$setup - $start})";

@promises = ();

for 2..16 -> $iters {
    $start = now;
    for (1..$iters) {
         @promises.push(start {
             my ($i, $j);
             $j = $r;
             loop ($i = 0; $i < $j; $i++) { }
         });
    }
    $setup = now;
    await Promise.allof(@promises);
    $stop = now;

    say "$iters iterations: {$stop - $start} (setup: {$setup - $start})";
}