Synchronous I/O reimplemented, lifting limtations on creating a handle on one thread and reading/writing it on another thread. Optimized UTF-8 decoding and reading data line by line. Dynamic optimization improvements for named parameters and more accurate type information propagation when dead code is eliminated. Further Unicode support and optimization. More features in asynchronous process handling. And many other bug fixes, new features, and optimizations.
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.