On Thursday, 13 January 2022 at 11:57:41 UTC, Araq wrote:
But the time it takes depends on the number of threads it has to stop and the amount of live memory of your heap. If it took 4ms regardless of these factors it wouldn't be bad, but that's not how D's GC works...
Sadly fast scanning is still bad, unless you are on an architecture where you can scan without touching the caches. If you burst through gigabytes of memory then you have a negative effect on real time threads that expect lookup tables to be in the caches. That means you need more headroom in real time threads, so you sacrifice the quality of work done by real time threads by saturating the memory data bus.
It would be better to have a concurrent collector that slowly crawls or just take the predicable overhead of ARC that is distributed fairly even in time (unless you do something silly).
