Seems like you were hitting: runtime: Large maps cause significant GC pauses #9477 [0]
Looks like this issue was resolved for maps that don't contain pointers by [1]. From the article, sounds like the map keys were strings (which do contain pointers, so the map would need to be scanned by the GC).
If pointers in the map keys and values could be avoided, it would have (if my understanding is correct) removed the need for the GC to scan the map. You could do this for example by replacing string keys with fixed size byte arrays. Curious if you experimented this approach?
Looks like this issue was resolved for maps that don't contain pointers by [1]. From the article, sounds like the map keys were strings (which do contain pointers, so the map would need to be scanned by the GC).
If pointers in the map keys and values could be avoided, it would have (if my understanding is correct) removed the need for the GC to scan the map. You could do this for example by replacing string keys with fixed size byte arrays. Curious if you experimented this approach?
[0] https://github.com/golang/go/issues/9477
[1] https://go-review.googlesource.com/c/go/+/3288