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This series adds manual control, > > opening more use cases. > > > > For example, setting CPUs aside for selected fair tasks at runtime while > > steering other fair tasks toward the remaining CPUs. > > Hi Yury, > > I've been trying to do this with crutches in user-space for a long time. Thanks for implementing this in the kernel, and with a convenient user interface. > > > > > A user can mark a CPU non-preferred and pin a workload to it. Fair tasks > > whose affinity includes preferred CPUs are steered away, while tasks > > whose allowed CPUs contain no preferred CPU can still run there. The CPU > > stays online, task affinity is preserved, and the selection can be > > reversed without rebooting: > > > > # rmmod steal_governor > > # echo 0 > /sys/devices/system/cpu/cpu3/preferred > > # taskset -c 3 ./my_workload > > # echo 1 > /sys/devices/system/cpu/cpu3/preferred > > My use-case (being a compiler optimization engineer) is to pin benchmarks to specific cores, and stop the system from using those cores even when the cores are idle. This prevents L1/L2 cache pollution and makes performance numbers more stable. Hi Maxim, Thank you for the feedback. I agree, this trick with pinning a workload to an non-preferred CPU looks promising for benchmarking purposes, and probably for more. I'm going to split this series to the cleanup and follow-up parts. In the follow-up, I'll focus on this writable interface. I'll keep you in CC there. Thanks, Yury