> a very slow and conservative stop the world Mark & Sweep, which runs at every allocation It doesn't run on every allocation. It can only run during an alloca

> a very slow and conservative stop the world Mark & Sweep, which runs at every allocation It doesn't run on every allocation. It can only run during an allocation, but that doesn't mean it will, and it's hard to think of a standard use case in which it would run on every allocation. FTA: "The first thing to understand about D’s garbage collector is that it only runs during allocation, and only if there is no memory available to allocate."