Enum ParShape 

pub enum ParShape {
    Seq,
    Rayon(NonZeroUsize),
}

the shape of a Par: which kind of parallelism and how many threads, without the right to run anything. Copy, so workspace queries and thresholds can use it freely; it cannot be passed to any function that executes work.

Variants

Seq

sequential

Rayon(NonZeroUsize)

the global rayon threadpool with this many threads

Implementations

impl ParShape

pub fn dispatch_cost(self, width: NonZeroUsize) -> Duration

The cost of one parallel section of width participants on this shape, in the steady state (sections back to back); Duration::MAX for a sequential shape or width < 2. width is clamped to the degree of the shape.

• Team: the cost of the team token the shape was taken from (threadteam’s DispatchKind::Team, with the costs of that token’s pool).
• Rayon: the cost of the Rayon route at the place the calling thread is: InPool when it is a worker of the pool (a caller inside spindle::with_lock is one), Outside otherwise (the rows of the host table of threadteam, or the same numbers without the threadteam feature). The shape is read on the thread that decides, so the answer follows the caller, not the token.

pub fn min_dispatch_cost(self) -> Duration

The cheapest cost of one section over all widths of this shape (a lower bound of dispatch_cost at every width), Duration::MAX for a shape of degree below 2.

pub fn pays( self, estimate: Duration, sections: u32, width: NonZeroUsize, ) -> bool

Whether a region of serial time estimate that opens sections sections of width participants pays on this shape: estimate >= PAYS * sections * dispatch_cost(width). sections is the number of dispatches the region really performs.

pub fn pays_full(self, estimate: Duration, sections: u32) -> bool

pays at the full degree of the shape.

impl ParShape

pub const fn seq() -> Self

sequential

pub fn rayon(nthreads: usize) -> Self

Rayon(nthreads), or Rayon(rayon::current_num_threads()) when nthreads is zero

pub fn degree(self) -> usize

the number of threads that should ideally execute an operation of this shape

Trait Implementations

impl Clone for ParShape

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ParShape

impl Debug for ParShape

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

Formats the value using the given formatter.

impl Eq for ParShape

impl PartialEq for ParShape

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for ParShape