| use crate::job::*; |
| use crate::registry::Registry; |
| use crate::unwind; |
| use std::mem; |
| use std::sync::Arc; |
| |
| /// Fires off a task into the Rayon threadpool in the "static" or |
| /// "global" scope. Just like a standard thread, this task is not |
| /// tied to the current stack frame, and hence it cannot hold any |
| /// references other than those with `'static` lifetime. If you want |
| /// to spawn a task that references stack data, use [the `scope()` |
| /// function][scope] to create a scope. |
| /// |
| /// [scope]: fn.scope.html |
| /// |
| /// Since tasks spawned with this function cannot hold references into |
| /// the enclosing stack frame, you almost certainly want to use a |
| /// `move` closure as their argument (otherwise, the closure will |
| /// typically hold references to any variables from the enclosing |
| /// function that you happen to use). |
| /// |
| /// This API assumes that the closure is executed purely for its |
| /// side-effects (i.e., it might send messages, modify data protected |
| /// by a mutex, or some such thing). |
| /// |
| /// There is no guaranteed order of execution for spawns, given that |
| /// other threads may steal tasks at any time. However, they are |
| /// generally prioritized in a LIFO order on the thread from which |
| /// they were spawned. Other threads always steal from the other end of |
| /// the deque, like FIFO order. The idea is that "recent" tasks are |
| /// most likely to be fresh in the local CPU's cache, while other |
| /// threads can steal older "stale" tasks. For an alternate approach, |
| /// consider [`spawn_fifo()`] instead. |
| /// |
| /// [`spawn_fifo()`]: fn.spawn_fifo.html |
| /// |
| /// # Panic handling |
| /// |
| /// If this closure should panic, the resulting panic will be |
| /// propagated to the panic handler registered in the `ThreadPoolBuilder`, |
| /// if any. See [`ThreadPoolBuilder::panic_handler()`][ph] for more |
| /// details. |
| /// |
| /// [ph]: struct.ThreadPoolBuilder.html#method.panic_handler |
| /// |
| /// # Examples |
| /// |
| /// This code creates a Rayon task that increments a global counter. |
| /// |
| /// ```rust |
| /// # use rayon_core as rayon; |
| /// use std::sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT}; |
| /// |
| /// static GLOBAL_COUNTER: AtomicUsize = ATOMIC_USIZE_INIT; |
| /// |
| /// rayon::spawn(move || { |
| /// GLOBAL_COUNTER.fetch_add(1, Ordering::SeqCst); |
| /// }); |
| /// ``` |
| pub fn spawn<F>(func: F) |
| where |
| F: FnOnce() + Send + 'static, |
| { |
| // We assert that current registry has not terminated. |
| unsafe { spawn_in(func, &Registry::current()) } |
| } |
| |
| /// Spawns an asynchronous job in `registry.` |
| /// |
| /// Unsafe because `registry` must not yet have terminated. |
| pub(super) unsafe fn spawn_in<F>(func: F, registry: &Arc<Registry>) |
| where |
| F: FnOnce() + Send + 'static, |
| { |
| // We assert that this does not hold any references (we know |
| // this because of the `'static` bound in the interface); |
| // moreover, we assert that the code below is not supposed to |
| // be able to panic, and hence the data won't leak but will be |
| // enqueued into some deque for later execution. |
| let abort_guard = unwind::AbortIfPanic; // just in case we are wrong, and code CAN panic |
| let job_ref = spawn_job(func, registry); |
| registry.inject_or_push(job_ref); |
| mem::forget(abort_guard); |
| } |
| |
| unsafe fn spawn_job<F>(func: F, registry: &Arc<Registry>) -> JobRef |
| where |
| F: FnOnce() + Send + 'static, |
| { |
| // Ensure that registry cannot terminate until this job has |
| // executed. This ref is decremented at the (*) below. |
| registry.increment_terminate_count(); |
| |
| HeapJob::new({ |
| let registry = Arc::clone(registry); |
| move || { |
| registry.catch_unwind(func); |
| registry.terminate(); // (*) permit registry to terminate now |
| } |
| }) |
| .into_static_job_ref() |
| } |
| |
| /// Fires off a task into the Rayon threadpool in the "static" or |
| /// "global" scope. Just like a standard thread, this task is not |
| /// tied to the current stack frame, and hence it cannot hold any |
| /// references other than those with `'static` lifetime. If you want |
| /// to spawn a task that references stack data, use [the `scope_fifo()` |
| /// function](fn.scope_fifo.html) to create a scope. |
| /// |
| /// The behavior is essentially the same as [the `spawn` |
| /// function](fn.spawn.html), except that calls from the same thread |
| /// will be prioritized in FIFO order. This is similar to the now- |
| /// deprecated [`breadth_first`] option, except the effect is isolated |
| /// to relative `spawn_fifo` calls, not all threadpool tasks. |
| /// |
| /// For more details on this design, see Rayon [RFC #1]. |
| /// |
| /// [`breadth_first`]: struct.ThreadPoolBuilder.html#method.breadth_first |
| /// [RFC #1]: https://github.com/rayon-rs/rfcs/blob/master/accepted/rfc0001-scope-scheduling.md |
| /// |
| /// # Panic handling |
| /// |
| /// If this closure should panic, the resulting panic will be |
| /// propagated to the panic handler registered in the `ThreadPoolBuilder`, |
| /// if any. See [`ThreadPoolBuilder::panic_handler()`][ph] for more |
| /// details. |
| /// |
| /// [ph]: struct.ThreadPoolBuilder.html#method.panic_handler |
| pub fn spawn_fifo<F>(func: F) |
| where |
| F: FnOnce() + Send + 'static, |
| { |
| // We assert that current registry has not terminated. |
| unsafe { spawn_fifo_in(func, &Registry::current()) } |
| } |
| |
| /// Spawns an asynchronous FIFO job in `registry.` |
| /// |
| /// Unsafe because `registry` must not yet have terminated. |
| pub(super) unsafe fn spawn_fifo_in<F>(func: F, registry: &Arc<Registry>) |
| where |
| F: FnOnce() + Send + 'static, |
| { |
| // We assert that this does not hold any references (we know |
| // this because of the `'static` bound in the interface); |
| // moreover, we assert that the code below is not supposed to |
| // be able to panic, and hence the data won't leak but will be |
| // enqueued into some deque for later execution. |
| let abort_guard = unwind::AbortIfPanic; // just in case we are wrong, and code CAN panic |
| let job_ref = spawn_job(func, registry); |
| |
| // If we're in the pool, use our thread's private fifo for this thread to execute |
| // in a locally-FIFO order. Otherwise, just use the pool's global injector. |
| match registry.current_thread() { |
| Some(worker) => worker.push_fifo(job_ref), |
| None => registry.inject(&[job_ref]), |
| } |
| mem::forget(abort_guard); |
| } |
| |
| #[cfg(test)] |
| mod test; |