Module tiers 

CPU capacities and asymmetric packing priorities, the loader’s half of scx_rustsched’s tiers.rs and topology.rs. The capacities and the scheduling-domain spans come from scx_utils’ Topology. The ITMT priority and SD_ASYM_PACKING come from the kernel through the rust_cpu_priority() syscall program, since neither has a user-space ABI. The result goes to the BPF program per CPU, which translates it to CIDs at init.

Capacity and packing are separate kernel policies with separate tiers, 0 the most preferred in both. Capacity tiers group CPUs of close capacity; packing tiers group CPUs of equal priority, or follow the capacity tiers when the kernel does not pack.

Re-exports

use std::ffi::OsStr; 🔒

use anyhow::Context; 🔒

use anyhow::Result; 🔒

use anyhow::bail; 🔒

use anyhow::ensure; 🔒

use libbpf_rs::Btf; 🔒

use libbpf_rs::MapCore; 🔒

use libbpf_rs::MapFlags; 🔒

use libbpf_rs::Object; 🔒

use libbpf_rs::ProgramInput; 🔒

use libbpf_rs::btf::types::Composite; 🔒

use libbpf_rs::btf::types::Enum; 🔒

use libbpf_rs::btf::types::MemberAttr; 🔒

use libbpf_rs::btf::types::Struct; 🔒

Structs

Cpu

Tiers

Enums

CapacityMode

How capacities are chosen.

Constants

MAX_CPUS

The BPF program’s per-CPU table, see scx_rustsched’s tiers.rs.

Functions

capacity_tiers

Assign sorted, descending capacities to tiers. Each capacity is compared with the fastest CPU of the current tier rather than the previous CPU, so that a chain of small steps does not merge CPUs far apart.

domain_flags 🔒

The SD_ASYM_PACKING and SD_SHARE_CPUCAPACITY bits, enumerators of an anonymous kernel enum.

domain_offsets 🔒

struct sched_domain’s flags and child offsets.

priority_tiers

Packing tiers from (cpu, priority) pairs: equal priorities share a tier, the highest priority is tier 0. Returns the tier per pair, in the order given.