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If I understand well (please correct me :), the following strategy should address this concern (and the ones expressed in successive emails): - cpu.rt.max can be "runtime, period" (or "runtime, period, deadline") or "root". "root" gives the current behaviour when RT cgroup scheduling is not enabled (so, no need to disable it at build time :) - if cpu.rt.max is "root", the cgroup's FIFO/RR tasks are scheduled in the root cgroup - if cpu.rt.max is "root", the children cgroups can only have "root" in cpu.rt.max - if cpu.rt.max is not "root", then cpu.rt.min (or cpu.rt.internal) is "runtime, period" and describes the dl server for this cgroup's FIFO/RR tasks. - The default value for cpu.rt.min is copied from cpu.rt.max, so as a default all the CPU utilization of the cgroup is dedicated it its RT tasks - the admission test is: cpu.rt.min utilization plus the sum of the children's cpu.rt.max utilizations must be <= cpu.rt.max utilization; children can have cpu.rt.max="root" only if cpu.rt.max="root" Can this work? I think it avoids escaping the parents' cpu.rt.max, allows for a reasonable default (no-one should be forced to disable this feature), and should respect all the requirements... Or am I missing something? Thanks, Luca