Struct polars_core::POOL[][src]

pub struct POOL { /* fields omitted */ }

Methods from Deref<Target = ThreadPool>

Executes op within the threadpool. Any attempts to use join, scope, or parallel iterators will then operate within that threadpool.

Warning: thread-local data

Because op is executing within the Rayon thread-pool, thread-local data from the current thread will not be accessible.

Panics

If op should panic, that panic will be propagated.

Using install()
   fn main() {
        let pool = rayon::ThreadPoolBuilder::new().num_threads(8).build().unwrap();
        let n = pool.install(|| fib(20));
        println!("{}", n);
   }

   fn fib(n: usize) -> usize {
        if n == 0 || n == 1 {
            return n;
        }
        let (a, b) = rayon::join(|| fib(n - 1), || fib(n - 2)); // runs inside of `pool`
        return a + b;
    }

Returns the (current) number of threads in the thread pool.

Future compatibility note

Note that unless this thread-pool was created with a ThreadPoolBuilder that specifies the number of threads, then this number may vary over time in future versions (see the num_threads() method for details).

If called from a Rayon worker thread in this thread-pool, returns the index of that thread; if not called from a Rayon thread, or called from a Rayon thread that belongs to a different thread-pool, returns None.

The index for a given thread will not change over the thread’s lifetime. However, multiple threads may share the same index if they are in distinct thread-pools.

Future compatibility note

Currently, every thread-pool (including the global thread-pool) has a fixed number of threads, but this may change in future Rayon versions (see the num_threads() method for details). In that case, the index for a thread would not change during its lifetime, but thread indices may wind up being reused if threads are terminated and restarted.

Returns true if the current worker thread currently has “local tasks” pending. This can be useful as part of a heuristic for deciding whether to spawn a new task or execute code on the current thread, particularly in breadth-first schedulers. However, keep in mind that this is an inherently racy check, as other worker threads may be actively “stealing” tasks from our local deque.

Background: Rayon’s uses a work-stealing scheduler. The key idea is that each thread has its own deque of tasks. Whenever a new task is spawned – whether through join(), Scope::spawn(), or some other means – that new task is pushed onto the thread’s local deque. Worker threads have a preference for executing their own tasks; if however they run out of tasks, they will go try to “steal” tasks from other threads. This function therefore has an inherent race with other active worker threads, which may be removing items from the local deque.

Execute oper_a and oper_b in the thread-pool and return the results. Equivalent to self.install(|| join(oper_a, oper_b)).

Creates a scope that executes within this thread-pool. Equivalent to self.install(|| scope(...)).

See also: the scope() function.

Creates a scope that executes within this thread-pool. Spawns from the same thread are prioritized in relative FIFO order. Equivalent to self.install(|| scope_fifo(...)).

See also: the scope_fifo() function.

Creates a scope that spawns work into this thread-pool.

See also: the in_place_scope() function.

Creates a scope that spawns work into this thread-pool in FIFO order.

See also: the in_place_scope_fifo() function.

Spawns an asynchronous task in this thread-pool. This task will run in the implicit, global scope, which means that it may outlast the current stack frame – therefore, it cannot capture any references onto the stack (you will likely need a move closure).

See also: the spawn() function defined on scopes.

Spawns an asynchronous task in this thread-pool. This task will run in the implicit, global scope, which means that it may outlast the current stack frame – therefore, it cannot capture any references onto the stack (you will likely need a move closure).

See also: the spawn_fifo() function defined on scopes.

Trait Implementations

The resulting type after dereferencing.

Dereferences the value.

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Gets the TypeId of self. Read more

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Mutably borrows from an owned value. Read more

Performs the conversion.

Performs the conversion.

The alignment of pointer.

The type for initializers.

Initializes a with the given initializer. Read more

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Mutably dereferences the given pointer. Read more

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The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.