Somehow concluding that "By killing Memory Arenas, Go effectively capped its performance ceiling" seems quite misguided.
With time Go is also getting knobs, and turns out various GC algorithms are actually useful.
Also I kind of foresee they will discover there are reasons why multiple GC algorithms are desired, and used in other programming ecosystems, thus the older one might stay anyway.
The older GC algorithm won't stay, IIRC the plan is for it to be removed in 1.27 (it's kept for now just to give a fallback in case of bugs in the first release).
> Go 1.5’s GC ushers in a future where stop-the-world pauses are no longer a barrier to moving to a safe and secure language. It is a future where applications scale effortlessly along with hardware and as hardware becomes more powerful the GC will not be an impediment to better, more scalable software. It’s a good place to be for the next decade and beyond.
yes, that's quite literally what I meant by "GOGC has always been there". 1.5 was released 10 years ago, just 3 years after 1.0.
So to summarize: there is one knob (that has been there from basically the beginning), plus a second one (if you squint hard enough: GOMAXMEM), and absolutely no plans to add further ones, or to add alternative GCs.
Go isn't getting any new knobs, there are only two; that's nothing compared to 100's of options that old Java GCs had. Completely incomparable.
> and turns out various GC algorithms are actually useful.
I don't know what you're trying to say here, but I think I know why — you don't know either. Stop spitballing.
There are no "various GC algorithms" at play here at all. There is just a new algorithm that performs better. You can read all about it here: https://go.dev/blog/greenteagc. It's not an optional alternative GC, but a successor.