Enum ParShape 

pub enum ParShape {
    Seq,
    Team(NonZeroUsize, DispatchCosts),
}

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

Team(NonZeroUsize, DispatchCosts)

a threadteam team of this many participants, with the dispatch costs of the pool it belongs to (see ParShape::dispatch_cost)

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 is the cost of the team token the shape was taken from (threadteam’s DispatchKind::Team, with the costs of that token’s pool). Above the largest measured anchor of the row threadteam grows the cost linearly with the width (threadteam 0.1.1); faer keeps no second model.

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 team(nthreads: usize) -> Self

Team(nthreads) with the host default dispatch costs, zero treated as one

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