Alternative implementation of rendezvous experiment by Adam Warski discussed here https://softwaremill.com/limits-of-looms-performance/

SimpleRendezvous.java

package com.barlasgarden;

import java.util.concurrent.atomic.AtomicInteger;

public class SimpleRendezvous {

    public void test() throws Exception {
        long start = System.currentTimeMillis();

        final int max = 10_000_000;

        AtomicInteger transfer = new AtomicInteger(-1);

        Thread t1 = Thread.ofVirtual().start(() -> {
            for (int i = 0; i <= max; i++) {
                while (!transfer.compareAndSet(-1, i)) ;
            }
        });

        Thread t2 = Thread.ofVirtual().start(() -> {
            long acc = 0L;
            int v;
            for (int i = 0; i <= max; i++) {
                while ((v = transfer.compareAndExchange(i, -1)) == -1) ;
                acc += v;
            }

            assert acc == sumUpTo(max);
        });

        t1.join();
        t2.join();

        long end = System.currentTimeMillis();
        System.out.println("Took: " + (end - start) + " ms");
    }

    private long sumUpTo(int max) {
        return ((long) max * (max + 1)) / 2;
    }

    public static void main(String[] args) throws Exception {
        for (int i = 0; i < 10; i++) {
            new SimpleRendezvous().test();
        }
    }
}