* Peter Zijlstra <[email protected]> [2025-10-28 12:18:13]: > On Tue, Oct 28, 2025 at 04:12:54PM +0530, Srikar Dronamraju wrote: > > At present, scheduler scales CPU capacity for fair tasks based on time > > spent on irq and steal time. If a CPU sees irq or steal time, its > > capacity for fair tasks decreases causing tasks to migrate to other CPU > > that are not affected by irq and steal time. All of this is gated by > > NONTASK_CAPACITY. > > > > In virtualized setups, a CPU that reports steal time (time taken by the > > hypervisor) can cause tasks to migrate unnecessarily to sibling CPUs that > > appear to be less busy, only for the situation to reverse shortly. > > > > To mitigate this ping-pong behaviour, this change introduces a new > > scheduler feature flag: ACCT_STEAL which will control whether steal time > > contributes to non-task capacity adjustments (used for fair scheduling). > > Please don't use sched_feat like this. If this is something that wants > to be set by architectures move it to a normal static_branch (like eg. > sched_energy_present, sched_asymc_cpucapacity, sched_cluster_active, > sched_smt_present, sched_numa_balancing etc.).
Ok, Peter, will move it to a static_branch approach and post a v2. -- Thanks and Regards Srikar Dronamraju
