Since Ruby 3.3.0-preview2 YJIT generates more code than Ruby 3.2.2 YJIT, this can result in YJIT having a higher memory overlead. We put a lot of effort into making metadata more space-efficient, but it still uses more memory than Ruby 3.2.2 YJIT. We’re looking into skipping compilation of paths that are less frequently executed.
# This match takes 10 sec. in Ruby 3.1, and 0.003 sec. in Ruby 3.2
/^a*b?a*$/ =~ "a" * 50000 + "x"
而另外一組 regexp 也可以看出類似的效果:
用一些記憶體空間換取效能,降低被 DoS 的一些機會。另外一方面,引入了 regexp timeout 的 workaround,緩解真的被打的時候的資源消耗上限:
The optimization above cannot be applied to some kind of regular expressions, such as those including advanced features (e.g., back-references or look-around), or with a huge fixed number of repetitions. As a fallback measure, a timeout feature for Regexp matches is also introduced.
That being said, according to our benchmarks, we’ve been able to achieve speedups over the CRuby interpreter of 7% on railsbench, 19% on liquid template rendering, and 19% on activerecord.
Currently, only about 50% of instructions in railsbench are executed by YJIT, and the rest run in the interpreter, meaning that there is still a lot we can do to improve upon our current results.