They certainly are, when compared with many alternatives.
- Requires manual type annotations to achieve remotely reasonable performance
- Does no interesting optimisations around method dispatch
- Chokes on code which reassigns variables
- Doesn't model memory (sroa, store forwarding, alias analysis, concurrency...)
- Doesn't do code motion
- Has a decent, but not particularly good gc
Hotspot hits on all of these points.
It's true that if you hand-hold the compiler, you can get fairly reasonable machine code out of it, same as you can do with some c compilers these days. But it's 80s technology and it shows.
var x = MyAwesomeClassFactoryBeanTemplate.getBean().getFactoryInstance().createNewMyAwesomeClass(foo, bar);I'm working on a better, parallel but still far from Java state-of-the-art GC for SBCL <https://zenodo.org/record/7816398> - which presumably is some skin in the game.
Just compare the Nyxt web browser with any Java monster out there.
Secondly, we are speaking about dynamic languages over here, that keep using C and Fortran.
I didn't stress the garbage collector enough so I can say that LW is faster or slower than other CL implementations. I'm currently doing an algorithmic research where the strain on garbage collector is not really that big, it's mainly about numerical performance and SBCL is by far the best from what I tried - LW, SBCL, CCL, Clisp, ABCL, ECL. Garbage collector takes usually 1-2% of run time which isn't that bad. I suppose that if I stressed it more than LW garbage collector would outperform SBCL but that's only my theory based on target audience of LW.
If you have experience with Allegro and LispWorks and can compare it to other implementations, could yous hare it, please? I'm quite curious. There isn't much on the internet about this topic.
Are allegro and lispworks appreciably better? My understanding was that lispworks, at least, forked from cmucl a long time ago and put less work into python than sbcl did.