Please try a more recent Rakudo with the MoarVM (default) backend. I recommend 2016.04, but anything from 2016 should work.

moritz@pete:~$ perl6 -e 'my $thread = Thread.start({ for 1 .. 10 -> $v
+ { say $v }});'
1
2
3
4
5
6
7
8
9
10
moritz@pete:~$ perl6 --version
This is Rakudo version 2016.04-32-g4232204 built on MoarVM version 201
+6.04
implementing Perl 6.c.
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