On 11/19/25 11:50 AM, Shrikanth Hegde wrote:
Detailed problem statement and some of the implementation choices were discussed earlier[1]. [1]: https://lore.kernel.org/all/[email protected]/ This is likely the version which would be used for LPC2025 discussion on this topic. Feel free to provide your suggestion and hoping for a solution that works for different architectures and it's use cases. All the existing alternatives such as cpu hotplug, creating isolated partitions etc break the user affinity. Since number of CPUs to use change depending on the steal time, it is not driven by User. Hence it would be wrong to break the affinity. This series allows if the task is pinned only paravirt CPUs, it will continue running there. Changes compared v3[1]: - Introduced computation of steal time in powerpc code. - Derive number of CPUs to use and mark the remaining as paravirt based on steal values. - Provide debugfs knobs to alter how steal time values being used. - Removed static key check for paravirt CPUs (Yury) - Removed preempt_disable/enable while calling stopper (Prateek) - Made select_idle_sibling and friends aware of paravirt CPUs. - Removed 3 unused schedstat fields and introduced 2 related to paravirt handling. - Handled nohz_full case by enabling tick on it when there is CFS/RT on it. - Updated helper patch to override arch behaviour for easier debugging during development.
Sorry for creating confusion around last two patches. Sent out new version. https://lore.kernel.org/all/[email protected]/
