> I'm curious if they tried the Ballast[0] approach

From the essay, the issue discord had was that they were not triggering enough GCs. The ballast approach serves to tune the GC frequency down.

In Discord's case they were getting screwed by a periodic mandatory GC trigger.

> along with smaller cache's per service

They did use a smaller cache, but that increased their 99% since… there was now less stuff in the cache.