> When I moved them over to Kubernetes, I also applied CPU resource limit, each in its own pod. I set the limits based on what I measured when they were all running on PM2 ... but the same code running on Kubernetes ran with 10x less CPU overall. Why? Because the async code were not allowed to just run grabbing as much CPU as it can for as long as it can, and the kernel scheduler was able to fairly run. That allowed the entire system to run with less resources overall.

As someone who has advocated against Kubernetes CPU limits everywhere I've worked, I'm really struggling to see how they helped you here. The code used 10x less CPU with CPU limits, with no adverse effects? What were all those CPU cycles going before?