On Mon, Sep 23, 2024 at 07:20:04AM GMT, Joshua Hahn joshua.hahnjy@gmail.com wrote:
From: Joshua Hahn joshua.hahn6@gmail.com
v2 -> v3: Signed-off-by & renamed subject for clarity. v1 -> v2: Edited commit messages for clarity.
Thanks for the version changelog, appreciated!
...
Exposing this metric will allow users to accurately probe the niced CPU metric for each workload, and make more informed decisions when directing higher priority tasks.
Possibly an example of how this value (combined with some other?) is used for decisions could shed some light on this and justify adding this attribute.
Thanks, Michal
(I'll respond here to Tejun's message from v2 thread.)
On Tue, Sep 10, 2024 at 11:01:07AM GMT, Tejun Heo tj@kernel.org wrote:
I think it's as useful as system-wide nice metric is.
Exactly -- and I don't understand how that system-wide value (without any cgroups) is useful. If I don't know how many there are niced and non-niced tasks and what their runnable patterns are, the aggregated nice time can have ambiguous interpretations.
I think there are benefits to mirroring system wide metrics, at least ones as widely spread as nice.
I agree with benefits of mirroring of some system wide metrics when they are useful <del>but not all of them because it's difficult/impossible to take them away once they're exposed</del>. Actually, readers _should_ handle missing keys gracefuly, so this may be just fine.
(Is this nice time widely spread? (I remember the field from `top`, still not sure how to use it.) Are other proc_stat(5) fields different?
I see how this can be the global analog on leaf cgroups but interpretting middle cgroups with children of different cpu.weights?)