|
|
<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="API documentation for the Rust `scope_fifo` fn in crate `rayon_core`."><meta name="keywords" content="rust, rustlang, rust-lang, scope_fifo"><title>rayon_core::scope_fifo - Rust</title><link rel="stylesheet" type="text/css" href="../normalize.css"><link rel="stylesheet" type="text/css" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../dark.css"><link rel="stylesheet" type="text/css" href="../light.css" id="themeStyle"><script src="../storage.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="shortcut icon" href="../favicon.ico"><style type="text/css">#crate-search{background-image:url("../down-arrow.svg");}</style></head><body class="rustdoc fn"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../rayon_core/index.html'><div class='logo-container'><img src='../rust-logo.png' alt='logo'></div></a><div class="sidebar-elems"><p class='location'><a href='index.html'>rayon_core</a></p><script>window.sidebarCurrent = {name: 'scope_fifo', ty: 'fn', relpath: ''};</script><script defer src="sidebar-items.js"></script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><a id="settings-menu" href="../settings.html"><img src="../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class='fqn'><span class='out-of-band'><span id='render-detail'><a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class='inner'>−</span>]</a></span><a class='srclink' href='../src/rayon_core/scope/mod.rs.html#379-388' title='goto source code'>[src]</a></span><span class='in-band'>Function <a href='index.html'>rayon_core</a>::<wbr><a class="fn" href=''>scope_fifo</a></span></h1><pre class='rust fn'>pub fn scope_fifo<'scope, OP, R>(op: OP) -> R <span class="where fmt-newline">where<br> OP: for<'s> <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>(&'s <a class="struct" href="../rayon_core/struct.ScopeFifo.html" title="struct rayon_core::ScopeFifo">ScopeFifo</a><'scope>) -> R + 'scope + <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a>,<br> R: <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a>, </span></pre><div class='docblock'><p>Create a "fork-join" scope <code>s</code> with FIFO order, and invokes the
|
|
|
closure with a reference to <code>s</code>. This closure can then spawn
|
|
|
asynchronous tasks into <code>s</code>. Those tasks may run asynchronously with
|
|
|
respect to the closure; they may themselves spawn additional tasks
|
|
|
into <code>s</code>. When the closure returns, it will block until all tasks
|
|
|
that have been spawned into <code>s</code> complete.</p>
|
|
|
<h1 id="task-execution" class="section-header"><a href="#task-execution">Task execution</a></h1>
|
|
|
<p>Tasks in a <code>scope_fifo()</code> run similarly to <a href="fn.scope.html"><code>scope()</code></a>, but there's a
|
|
|
difference in the order of execution. Consider a similar example:</p>
|
|
|
|
|
|
<div class="example-wrap"><pre class="rust rust-example-rendered">
|
|
|
<span class="comment">// point start</span>
|
|
|
<span class="ident">rayon</span>::<span class="ident">scope_fifo</span>(<span class="op">|</span><span class="ident">s</span><span class="op">|</span> {
|
|
|
<span class="ident">s</span>.<span class="ident">spawn_fifo</span>(<span class="op">|</span><span class="ident">s</span><span class="op">|</span> { <span class="comment">// task s.1</span>
|
|
|
<span class="ident">s</span>.<span class="ident">spawn_fifo</span>(<span class="op">|</span><span class="ident">s</span><span class="op">|</span> { <span class="comment">// task s.1.1</span>
|
|
|
<span class="ident">rayon</span>::<span class="ident">scope_fifo</span>(<span class="op">|</span><span class="ident">t</span><span class="op">|</span> {
|
|
|
<span class="ident">t</span>.<span class="ident">spawn_fifo</span>(<span class="op">|</span><span class="kw">_</span><span class="op">|</span> ()); <span class="comment">// task t.1</span>
|
|
|
<span class="ident">t</span>.<span class="ident">spawn_fifo</span>(<span class="op">|</span><span class="kw">_</span><span class="op">|</span> ()); <span class="comment">// task t.2</span>
|
|
|
});
|
|
|
});
|
|
|
});
|
|
|
<span class="ident">s</span>.<span class="ident">spawn_fifo</span>(<span class="op">|</span><span class="ident">s</span><span class="op">|</span> { <span class="comment">// task s.2</span>
|
|
|
});
|
|
|
<span class="comment">// point mid</span>
|
|
|
});
|
|
|
<span class="comment">// point end</span></pre></div>
|
|
|
<p>The various tasks that are run will execute roughly like so:</p>
|
|
|
<pre><code class="language-notrust">| (start)
|
|
|
|
|
|
|
| (FIFO scope `s` created)
|
|
|
+--------------------+ (task s.1)
|
|
|
+-------+ (task s.2) |
|
|
|
| | +---+ (task s.1.1)
|
|
|
| | | |
|
|
|
| | | | (FIFO scope `t` created)
|
|
|
| | | +----------------+ (task t.1)
|
|
|
| | | +---+ (task t.2) |
|
|
|
| (mid) | | | | |
|
|
|
: | | + <-+------------+ (scope `t` ends)
|
|
|
: | | |
|
|
|
|<------+------------+---+ (scope `s` ends)
|
|
|
|
|
|
|
| (end)
|
|
|
</code></pre>
|
|
|
<p>Under <code>scope_fifo()</code>, the spawns are prioritized in a FIFO order on
|
|
|
the thread from which they were spawned, as opposed to <code>scope()</code>'s
|
|
|
LIFO. So in this example, we can expect <code>s.1</code> to execute before
|
|
|
<code>s.2</code>, and <code>t.1</code> before <code>t.2</code>. Other threads also steal tasks in
|
|
|
FIFO order, as usual. Overall, this has roughly the same order as
|
|
|
the now-deprecated <a href="struct.ThreadPoolBuilder.html#method.breadth_first"><code>breadth_first</code></a> option, except the effect is
|
|
|
isolated to a particular scope. If spawns are intermingled from any
|
|
|
combination of <code>scope()</code> and <code>scope_fifo()</code>, or from different
|
|
|
threads, their order is only specified with respect to spawns in the
|
|
|
same scope and thread.</p>
|
|
|
<p>For more details on this design, see Rayon <a href="https://github.com/rayon-rs/rfcs/blob/master/accepted/rfc0001-scope-scheduling.md">RFC #1</a>.</p>
|
|
|
<h1 id="panics" class="section-header"><a href="#panics">Panics</a></h1>
|
|
|
<p>If a panic occurs, either in the closure given to <code>scope_fifo()</code> or
|
|
|
in any of the spawned jobs, that panic will be propagated and the
|
|
|
call to <code>scope_fifo()</code> will panic. If multiple panics occurs, it is
|
|
|
non-deterministic which of their panic values will propagate.
|
|
|
Regardless, once a task is spawned using <code>scope.spawn_fifo()</code>, it
|
|
|
will execute, even if the spawning task should later panic.
|
|
|
<code>scope_fifo()</code> returns once all spawned jobs have completed, and any
|
|
|
panics are propagated at that point.</p>
|
|
|
</div></section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>⏎</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g., <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g., <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g., <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../";window.currentCrate = "rayon_core";</script><script src="../aliases.js"></script><script src="../main.js"></script><script defer src="../search-index.js"></script></body></html> |
