[jonasn]

Thanks for the detailed read and the great questions!

Regarding the colors and thread counts in Figure 4: the key piece of context here is that the application thread (the Main thread) is completely paused during this phase. It isn't actually running anything at all. Because the application is halted, only the GC threads are doing active work. Therefore, rather than three threads running at once, we strictly have two things running concurrently. This is a helpful piece of feedback and I'll make sure to make this clearer in future writings.

Good eye on the 101% wall time. That was due to a minor bug in my plotting script that specifically affected the GC plots with no concurrent time. I have corrected this and updated the post. The fixed plot should be visible on the site in a future near you just as soon as the edge caches invalidate.