so write a specialized GC for the task in C or C++.
C++ can always win!
JVM has hotspot? use profile guided optmization in C!
There is no escape!
If you are one of the three people in the world that can do it. ;-)
Re:Debunking the Java Performance Myth
by fauigerzigerk on Sunday October 22, 2017 @01:07PM
(#15527761)
Just use an arena allocator (or similar) where appropriate. It's not difficult and it's how C, C++ and Rust win all micro benchmarks that involve memory allocation: http://benchmarksgame.alioth.debian.org/u64q/binarytrees.htm...
"A JVM does that???" by Cliff Click is a good introduction on what can go in the background.