Slurpy Buf.list

2015.12

$ perl6 -v
This is Rakudo version 2015.12 built on MoarVM version 2015.12
implementing Perl 6.c.
[sog@monica Blob]$ perl6 bench.pl6
Benchmark: 
Timing 1000 iterations of list, passli...
      list: 1.2851 wallclock secs @ 778.1340/s (n=1000)
    passli: 1.3605 wallclock secs @ 735.0190/s (n=1000)

2afe797 feb-25

$ perl6 -v
This is Rakudo version 2016.02-27-g2afe79f built on MoarVM version 2016.02
implementing Perl 6.c.
[sog@monica Blob]$ perl6 bench.pl6 
Benchmark: 
Timing 1000 iterations of list, passli...
      list: 1.4013 wallclock secs @ 713.6286/s (n=1000)
    passli: 1.6245 wallclock secs @ 615.5784/s (n=1000)

bench.pl6

use v6;
use Bench;
my $b = Bench.new;
my $buf = Buf.new(0 xx 1000);

#multi sub foo(@vals) { @vals.elems };
#multi sub foo(*@vals) { foo(@vals) };
sub foo(*@vals) { @vals.elems };

$b.timethese(1000, {
    list   => { my @li = $buf.list; foo(@li); },
    passli => { foo($buf.list) },
});

f25d41c feb-25

$ perl6 -v
This is Rakudo version 2016.02-30-gf25d41c built on MoarVM version 2016.02
implementing Perl 6.c.
[sog@monica Blob]$ perl6 bench.pl6 
Benchmark: 
Timing 1000 iterations of list, passli...
      list: 1.2354 wallclock secs @ 809.4610/s (n=1000)
    passli: 26.6272 wallclock secs @ 37.5556/s (n=1000)

nom

$ perl6 -v
This is Rakudo version 2016.02-100-g4a0ba74 built on MoarVM version 2016.02-8-ga329e2d
implementing Perl 6.c.
[sog@monica Blob]$ perl6 bench.pl6
Benchmark: 
Timing 1000 iterations of list, passli...
      list: 1.2906 wallclock secs @ 774.8104/s (n=1000)
    passli: 28.7112 wallclock secs @ 34.8296/s (n=1000)

The real problem isn't the change in Blob/Buf.list, but the really bad interactions between an Interator / Seq vs an slurpy argument, as proved by uncommenting the multis in bench.pl above.

So the solution to the original issue (creating a CArray from a Buf) can be solved adding a non slurpy candidate CArray.new(@vals)