Struct CpuTopology 

pub struct CpuTopology { /* private fields */ }

The SMT layout of the logical CPUs this process may run on: for each allowed CPU, in ascending id order, the set of CPUs sharing its physical core.

An empty sibling list means “sysfs did not answer for this CPU”. Such a CPU is treated as a physical core of its own and is never merged with another unknown one — guessing that two unreadable CPUs are siblings would silently halve the pool on any host that simply has no topology/ directory (a container with a masked /sys, some hypervisors, anything non-Linux), and that regression arrives with no error attached to it.

Implementations

impl CpuTopology

pub fn from_sibling_lists<I>(entries: I) -> Self

where I: IntoIterator<Item = (usize, Vec<usize>)>,

Build a topology from explicit sibling lists — the injection point that makes every rule in this module testable on a host with no SMT, no root, and no particular CPU count.

Entries are sorted by CPU id and deduplicated, because the rules pick the first allowed CPU of each physical core as that core’s representative and that choice must not depend on the order the caller happened to enumerate in.

pub fn read_from(root: &Path, allowed: &[usize]) -> Self

Read {root}/cpu{n}/topology/thread_siblings_list for each CPU in allowed. A CPU whose file is missing or unreadable gets an empty sibling list (see the type docs: it becomes its own core), so a host without sysfs topology degrades to one worker per allowed CPU instead of erroring out mid-boot.

pub fn detect() -> Self

This host’s topology: SYSFS_CPU_ROOT restricted to process_affinity_cpus.

pub fn allowed_cpus(&self) -> Vec<usize>

The allowed logical CPUs, ascending.

pub fn len(&self) -> usize

Number of allowed logical CPUs, SMT siblings included.

pub fn is_empty(&self) -> bool

Whether no CPU at all is described.

Trait Implementations

impl Clone for CpuTopology

fn clone(&self) -> CpuTopology

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CpuTopology

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for CpuTopology

fn default() -> CpuTopology

Returns the “default value” for a type.

impl Eq for CpuTopology

impl PartialEq for CpuTopology

fn eq(&self, other: &CpuTopology) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for CpuTopology