Since it is always interesting to see where D's GC stands and what is being done on other platforms, here is a Red-Hat article about their improvements on the Shenandoah GC implementation, which achieves around 328 µs pause for heaps sized in TB. https://developers.redhat.com/articles/2021/09/16/shenandoah-openjdk-17-sub-millisecond-gc-pauses#