As an educated guess: Sparkplug is very similar in design to SpiderMonkey's baseline compiler. I ran a quick test a few weeks ago to see what the performance de

As an educated guess: Sparkplug is very similar in design to SpiderMonkey's baseline compiler. I ran a quick test a few weeks ago to see what the performance delta was between SM's baseline compiler and baseline interpreter, and going from the interpreter to the compiler was about a 2x speedup. Based on that, I'd expect that you're looking at a ~2-4x speedup from the interpreter to Sparkplug. Edited to add: Which is a very good result! Congrats to the V8 team for landing this!