The Moving to Moose Hackathon, and NQP on QAST

It’s already been almost a week and a half since I returned from the Moving To Moose Hackathon. Annoyingly, the first thing that happened on my return is that I got sick. This has combined badly with a very busy work schedule, meaning I’ve struggled to get the rest I need to really recover. As a result, I’ve mostly fallen off the Perl 6 grid over the last week. Anyway, I’ll be fine, though it may take another week before I’m really in decent shape and able to be productive on Rakudo and NQP again.

Anyway, let me talk about the days I spent at the hackathon. It was held at the Preikestolen Mountain Lodge, which gives it the title of “most beautiful hackathon venue I’ve ever been at”, by some margin. Getting to such a remote place with public transport would not have been entirely easy; thankfully, did an incredible job of organizing their own transport, hiring a minibus that was even adorned with the lovely logo. The lodge itself was by a lake surrounded by hills, and one of the hackrooms had delightful views. The lodge restaurant also had beautiful views, and it was lovely to be up there at dinner and watch the sunset. Talk about an inspiring location…

I’ve not really been that involved with Moose, or the Perl 5 MOP project, so you may wonder how I ended up at the hackathon. The reason was that I was invited to share my experiences working on 6model, and thus had various interesting discussions about that. I designed and built 6model in relative isolation (though taking many existing meta-object systems as inspiration), thus it was nice to be sat in a room with interesting discussions about MOPs going on. Overall I feel good about what is happening with the Perl 5 MOP work, and having witnessed the work on it in progress I think it’s going good places. I think we’ll be able to get good interop between Perl 5 and Perl 6 objects also.

So what did I hack on? Having a good chunk of time where I could focus entirely on Perl related things meant it was a good chance to get one of the Big Tricky Things on the Rakudo and NQP roadmap taken care of: the moving of NQP to use our new backend, QAST. I’d already got Rakudo largely moved over to using this. In some senses, you’d think getting Rakudo using QAST would be a more difficult task; in reality, Rakudo actually is much more loosely coupled to the VM than NQP has traditionally been. Mostly that’s because a bit more design effort has gone into Rakudo, since it’s the more important product. NQP has more filled the role of “the thing we use to build the product”, and thus has mostly been improved on an as-needed basis. (Both pmichaud and I think NQP can and should be an interesting product in its own right, as a toolchain for compiler construction. But Rakudo has priority.)

Anyway, the Big Result is that NQP is now moved over to the new backend toolchain. Just by doing that, we’ve managed to get some performance improvements thanks to better code generation. Thus you can expect the next release of Rakudo to compile your programs a little faster (we’re talking 5% – 10%, which is welcome even if not huge). This has in turn meant much other code can be eliminated, NQP needs less memory to build, and various hacks have gone away. For example, in the course of the work I re-unified multi-method and multi-sub dispatch in NQP, which had diverged a little some time ago.

This also means the last large dependency that NQP had on code written in Parrot’s Intermediate Language is now gone. This is not only good for maintainability (it’s much better to maintain code in a high level language), but also removes the final big blocker for porting NQP to other VMs. Having spoken to plenty of people on this matter during events over the summer, I sense there’s a lot of enthusiasm for it – especially from those whose views I consider most worth listening to – and I look forward to digging into it.

Other things that this has unlocked is working on giving NQP further native type support and an optimizer. These together will also enable us to improve the performance of NQP execution, in turn facilitating further improvements to the compilation performance of Rakudo. I’m hopeful of getting to those in the course of the coming month; they won’t land for the September release, but having them for the October one seems quite comfortably achievable. We’ll see. :-)

Anyway, I’d like to finish up by thanking for organizing yet another awesome hackathon. It was very well organized and run, and I’m really grateful for all the time, effort and money they put in to it. Not to mention that they’ve a really nice bunch of individuals also. Great work! :-)

This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.