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While I agree that CPU limits tend to make your performance worse, I don't think the delivery of the post is all too convincing (and is pretty heavy on the LLM-

While I agree that CPU limits tend to make your performance worse, I don't think the delivery of the post is all too convincing (and is pretty heavy on the LLM-isms that it's putting me off from reading). It mentions that a cpu request is a guarantee, but how is that enforced? If I have 32 pods running on a 32 core machine, each with 1cpu requested, what stops one of those pods using an unfair share? I assume we just rely on the Linux scheduler. If I have 16 pods with 1cpu and 1 pod with 16cpu, does the Linux scheduler make sure to give the 16cpu pod more time? Or are we back to using cgroups.

croemer 2mo ago
Requests are guaranteed no matter what. > If I have 16 pods with 1cpu and 1 pod with 16cpu, does the Linux scheduler make sure to give the 16cpu pod more time? Yes if there's CPU pressure the 16cpu will get 16x more than 1cpu.
Sayrus 2mo ago
Each pod has weight. These are written to your cgroup (cpu.weight in CGroups V2). CFS is scheduling based on these weights. There's a part about it: https://github.com/inevolin/k8s-cpu-limits-analyzed#3-without-limits-who-shares-the-cpu-meet-cfs https://github.com/inevolin/k8s-cpu-limits-analyzed#3-withou...
toast0 2mo ago
> If I have 32 pods running on a 32 core machine, each with 1cpu requested, what stops one of those pods using an unfair share? I don't use all this fancy stuff, but wouldn't you set that up as each of the 32 pods is limited to running on a specific core? No sense letting them each run on all cores, because all of the X per core will get too big.
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