GoKawiilEngineer finds swap can trigger 40ms Go GC stop-the-world pauses
A developer testing swap space to absorb memory spikes in production discovered that Go's garbage collector can experience severe stop-the-world pauses when its internal bookkeeping metadata gets swapped to disk. In a test on a Hetzner server, a median GC pause of about 51 microseconds ballooned to 40 milliseconds when that metadata resided on NVMe storage, with BPF tracing showing 228 page faults consuming nearly all of the pause time inside the collector's span-set reset routine.