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Architectures can use SD_ASYM_PACKING to describe preferred CPU ordering at the SMT scheduling domain. Some systems benefit from this policy, but their firmware cannot describe the preference and inferring it from the CPU model would embed a platform-specific policy in the kernel. Add sched_smt_asym_packing=on boot option to force SD_ASYM_PACKING at the SMT level. Omitting the option preserves the topology provided by the architecture or firmware. Apply the override centrally to domains with SD_SHARE_CPUCAPACITY so it also covers architectures with custom SMT topology callbacks, including powerpc. When enabled, priority remains defined by arch_asym_cpu_priority(). The weak default prefers lower-numbered logical CPUs, while architecture overrides remain authoritative. Siblings with equal priorities remain unordered. In particular, x86 with CONFIG_SCHED_MC_PRIO normally gives both SMT siblings the same core priority, so enabling the option there does not prioritize a sibling. Signed-off-by: Andrea Righi <arighi@nvidia.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20260929165538.726616-3-arighi@nvidia.com |
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| .. | ||
| ext | ||
| autogroup.c | ||
| autogroup.h | ||
| build_policy.c | ||
| build_utility.c | ||
| clock.c | ||
| completion.c | ||
| core_sched.c | ||
| core.c | ||
| cpuacct.c | ||
| cpudeadline.c | ||
| cpudeadline.h | ||
| cpufreq_schedutil.c | ||
| cpufreq.c | ||
| cpupri.c | ||
| cpupri.h | ||
| cputime.c | ||
| deadline.c | ||
| debug.c | ||
| fair.c | ||
| features.h | ||
| idle.c | ||
| isolation.c | ||
| loadavg.c | ||
| Makefile | ||
| membarrier.c | ||
| pelt.c | ||
| pelt.h | ||
| psi.c | ||
| rq-offsets.c | ||
| rt.c | ||
| sched-pelt.h | ||
| sched.h | ||
| smp.h | ||
| stats.c | ||
| stats.h | ||
| stop_task.c | ||
| swait.c | ||
| syscalls.c | ||
| topology.c | ||
| wait_bit.c | ||
| wait.c | ||