Hello, Michal. On Mon, Sep 02, 2024 at 05:45:39PM +0200, Michal Koutný wrote: > - It makes (some) sense only on leave cgroups (where variously nice'd > tasks are competing against each other). Not so much on inner node > cgroups (where it's a mere sum but sibling cgroups could have different > weights, so the absolute times would contribute differently). > > - When all tasks have nice > 0 (or nice <= 0), it loses any information > it could have had. I think it's as useful as system-wide nice metric is. It's not a versatile metric but is widely available and understood and people use it. Maybe a workload is split across a sub-hierarchy and they wanna collect how much lowpri threads are consuming. cpu.stats is available without cpu control being enabled and people use it as a way to just aggregate metrics across a portion of the system. > (Thus I don't know whether to commit to exposing that value via cgroups.) > > I wonder, wouldn't your use case be equally served by some > post-processing [1] of /sys/kernel/debug/sched/debug info which is > already available? ... > above is only for CPU nr=0. So processing would mean sampling that file > over all CPUs and time. I think there are benefits to mirroring system wide metrics, at least ones as widely spread as nice. Thanks. -- tejun
