Call frame management overhauled and simplified, improving performance of multi-threaded programs as well as programs that keep large numbers of closures in memory. Improvements to serialization, resulting in smaller output. Support for loading bytecode from a buffer and a file handle. A range of garbage collection and concurrency bug fixes. And a whole bunch of other improvements!
Short for "Metamodel On A Runtime", MoarVM is a virtual machine built especially for Rakudo Perl 6 and the NQP Compiler Toolchain. It uses dynamic optimization techniques to detect hot code and produce specialized versions for the types that show up at runtime. The most popular backend for Rakudo Perl 6, MoarVM stands out by:
For long-running workloads where startup time doesn't matter and you need tried-and-tested threading support, Rakudo on the JVM may be a better bet. It may also - once the slow startup is overcome - win on performance for some workloads, once its sophisticated JIT compiler gets to work. MoarVM is under active development in these areas, and the gap continues to close.