It's not clear to me what the max parallelism should actually be on a container with a CPU limit of .5. To my understanding that limits CPU time the container can use within a certain time interval, but doesn't actually limit the parallel processes an application can run. In other words that container with .5 on the CPU limit can indeed use all 16 physical cores of that machine. It'll just burn through it's budget 16x faster. If that's desirable vs limiting itself to one process is going to be highly application dependent and not something kubernetes and docker can just tell you.
It won’t burn through the budget faster by having more cores. You’re given a fixed time-slice of the whole CPU (in K8s, caveats below), whether you use all the cores or just one doesn’t particularly matter. On one hand, it would be would nice to be able to limit workloads on K8s to a subset of cores too, on the other, I can only imagine how much catastrophically complex that would make scheduling and optimisation.
Caveats: up to the number of cores exposed to your VM. I also believe the later versions of K8s let you do some degree of workload-core pinning and I don’t yet know how that interacts with core availability .
