10 ms·
A new register allocator for ZJIT
- ksec 4mo agoGlad to read news on Ruby ZJIT development. I wonder if ZJIT is being used in production at Shopify yet?
- molf 4mo agoI have no idea; but I presume they don't, given that ZJIT today is still much slower than YJIT? [1] [1]: https://rubybench.github.io https://rubybench.github.io
- kimos 4mo agoUsed in production? Probably not yet. But likely tested in production on a small %. They’ve gotten practiced at using the Shopify Rails monolith as the biggest test suite and regression tests for Rails and Ruby.
- ksec 4mo agoYes that is what I meant, should have worded it as tested in production. Hopefully it is no longer experimental in Ruby 4.1.
- djwatson24 4mo agoI’ve always wondered about linear scan vs SSA based spilling & regalloc, like libfirm & qbe use: ‘Register spilling and live-range splitting for SSA-form programs’ and ‘Preference-Guided Register Assignment’ It’s much cleaner to code, since you don’t need to generate live ranges explicitly, and can break it up in two passes. Linear scan creates new inactive /active intervals, while the ssa form allocators just reuse the ssa graph. I’ve never benchmarked them back to back though.
- nryoo 4mo agoHow big is the lifetime holes thing in practice? On loops the contiguous-interval model spills way more than it should. Wondering if that alone explains most of the YJIT gap.