<!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="Source of the Rust file `/home/sangenya/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.1/src/sleep/mod.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>mod.rs - source</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="../../../light.css" id="themeStyle"><link rel="stylesheet" type="text/css" href="../../../dark.css" disabled ><link rel="stylesheet" type="text/css" href="../../../ayu.css" disabled ><script id="default-settings"></script><script src="../../../storage.js"></script><script src="../../../crates.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="icon" type="image/svg+xml" href="../../../favicon.svg">
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</pre><pre class="rust">
<span class="doccomment">//! Code that decides when workers should go to sleep. See README.md</span>
<span class="doccomment">//! for an overview.</span>
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::latch::CoreLatch</span>;
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::log::Event</span>::<span class="kw-2">*</span>;
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::log::Logger</span>;
<span class="kw">use</span> <span class="ident">crossbeam_utils::CachePadded</span>;
<span class="kw">use</span> <span class="ident">std::sync::atomic::Ordering</span>;
<span class="kw">use</span> <span class="ident">std::sync</span>::{<span class="ident">Condvar</span>, <span class="ident">Mutex</span>};
<span class="kw">use</span> <span class="ident">std::thread</span>;
<span class="kw">use</span> <span class="ident">std::usize</span>;
<span class="kw">mod</span> <span class="ident">counters</span>;
<span class="kw">use</span> <span class="self">self</span><span class="ident">::counters</span>::{<span class="ident">AtomicCounters</span>, <span class="ident">JobsEventCounter</span>};
<span class="doccomment">/// The `Sleep` struct is embedded into each registry. It governs the waking and sleeping</span>
<span class="doccomment">/// of workers. It has callbacks that are invoked periodically at significant events,</span>
<span class="doccomment">/// such as when workers are looping and looking for work, when latches are set, or when</span>
<span class="doccomment">/// jobs are published, and it either blocks threads or wakes them in response to these</span>
<span class="doccomment">/// events. See the [`README.md`] in this module for more details.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`README.md`] README.md</span>
<span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">struct</span> <span class="ident">Sleep</span> {
<span class="ident">logger</span>: <span class="ident">Logger</span>,
<span class="doccomment">/// One "sleep state" per worker. Used to track if a worker is sleeping and to have</span>
<span class="doccomment">/// them block.</span>
<span class="ident">worker_sleep_states</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">CachePadded</span><span class="op"><</span><span class="ident">WorkerSleepState</span><span class="op">></span><span class="op">></span>,
<span class="ident">counters</span>: <span class="ident">AtomicCounters</span>,
}
<span class="doccomment">/// An instance of this struct is created when a thread becomes idle.</span>
<span class="doccomment">/// It is consumed when the thread finds work, and passed by `&mut`</span>
<span class="doccomment">/// reference for operations that preserve the idle state. (In other</span>
<span class="doccomment">/// words, producing one of these structs is evidence the thread is</span>
<span class="doccomment">/// idle.) It tracks state such as how long the thread has been idle.</span>
<span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">struct</span> <span class="ident">IdleState</span> {
<span class="doccomment">/// What is worker index of the idle thread?</span>
<span class="ident">worker_index</span>: <span class="ident">usize</span>,
<span class="doccomment">/// How many rounds have we been circling without sleeping?</span>
<span class="ident">rounds</span>: <span class="ident">u32</span>,
<span class="doccomment">/// Once we become sleepy, what was the sleepy counter value?</span>
<span class="doccomment">/// Set to `INVALID_SLEEPY_COUNTER` otherwise.</span>
<span class="ident">jobs_counter</span>: <span class="ident">JobsEventCounter</span>,
}
<span class="doccomment">/// The "sleep state" for an individual worker.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Default</span>)]</span>
<span class="kw">struct</span> <span class="ident">WorkerSleepState</span> {
<span class="doccomment">/// Set to true when the worker goes to sleep; set to false when</span>
<span class="doccomment">/// the worker is notified or when it wakes.</span>
<span class="ident">is_blocked</span>: <span class="ident">Mutex</span><span class="op"><</span><span class="ident">bool</span><span class="op">></span>,
<span class="ident">condvar</span>: <span class="ident">Condvar</span>,
}
<span class="kw">const</span> <span class="ident">ROUNDS_UNTIL_SLEEPY</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="number">32</span>;
<span class="kw">const</span> <span class="ident">ROUNDS_UNTIL_SLEEPING</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="ident">ROUNDS_UNTIL_SLEEPY</span> <span class="op">+</span> <span class="number">1</span>;
<span class="kw">impl</span> <span class="ident">Sleep</span> {
<span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">logger</span>: <span class="ident">Logger</span>, <span class="ident">n_threads</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Sleep</span> {
<span class="ident">Sleep</span> {
<span class="ident">logger</span>,
<span class="ident">worker_sleep_states</span>: (<span class="number">0</span>..<span class="ident">n_threads</span>).<span class="ident">map</span>(<span class="op">|</span><span class="kw">_</span><span class="op">|</span> <span class="ident">Default::default</span>()).<span class="ident">collect</span>(),
<span class="ident">counters</span>: <span class="ident">AtomicCounters::new</span>(),
}
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn</span> <span class="ident">start_looking</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">worker_index</span>: <span class="ident">usize</span>, <span class="ident">latch</span>: <span class="kw-2">&</span><span class="ident">CoreLatch</span>) <span class="op">-</span><span class="op">></span> <span class="ident">IdleState</span> {
<span class="self">self</span>.<span class="ident">logger</span>.<span class="ident">log</span>(<span class="op">|</span><span class="op">|</span> <span class="ident">ThreadIdle</span> {
<span class="ident">worker</span>: <span class="ident">worker_index</span>,
<span class="ident">latch_addr</span>: <span class="ident">latch</span>.<span class="ident">addr</span>(),
});
<span class="self">self</span>.<span class="ident">counters</span>.<span class="ident">add_inactive_thread</span>();
<span class="ident">IdleState</span> {
<span class="ident">worker_index</span>,
<span class="ident">rounds</span>: <span class="number">0</span>,
<span class="ident">jobs_counter</span>: <span class="ident">JobsEventCounter::DUMMY</span>,
}
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn</span> <span class="ident">work_found</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">idle_state</span>: <span class="ident">IdleState</span>) {
<span class="self">self</span>.<span class="ident">logger</span>.<span class="ident">log</span>(<span class="op">|</span><span class="op">|</span> <span class="ident">ThreadFoundWork</span> {
<span class="ident">worker</span>: <span class="ident">idle_state</span>.<span class="ident">worker_index</span>,
<span class="ident">yields</span>: <span class="ident">idle_state</span>.<span class="ident">rounds</span>,
});
<span class="comment">// If we were the last idle thread and other threads are still sleeping,</span>
<span class="comment">// then we should wake up another thread.</span>
<span class="kw">let</span> <span class="ident">threads_to_wake</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">counters</span>.<span class="ident">sub_inactive_thread</span>();
<span class="self">self</span>.<span class="ident">wake_any_threads</span>(<span class="ident">threads_to_wake</span> <span class="kw">as</span> <span class="ident">u32</span>);
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn</span> <span class="ident">no_work_found</span>(
<span class="kw-2">&</span><span class="self">self</span>,
<span class="ident">idle_state</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">IdleState</span>,
<span class="ident">latch</span>: <span class="kw-2">&</span><span class="ident">CoreLatch</span>,
<span class="ident">has_injected_jobs</span>: <span class="kw">impl</span> <span class="ident">FnOnce</span>() <span class="op">-</span><span class="op">></span> <span class="ident">bool</span>,
) {
<span class="kw">if</span> <span class="ident">idle_state</span>.<span class="ident">rounds</span> <span class="op"><</span> <span class="ident">ROUNDS_UNTIL_SLEEPY</span> {
<span class="ident">thread::yield_now</span>();
<span class="ident">idle_state</span>.<span class="ident">rounds</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
} <span class="kw">else</span> <span class="kw">if</span> <span class="ident">idle_state</span>.<span class="ident">rounds</span> <span class="op">=</span><span class="op">=</span> <span class="ident">ROUNDS_UNTIL_SLEEPY</span> {
<span class="ident">idle_state</span>.<span class="ident">jobs_counter</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">announce_sleepy</span>(<span class="ident">idle_state</span>.<span class="ident">worker_index</span>);
<span class="ident">idle_state</span>.<span class="ident">rounds</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
<span class="ident">thread::yield_now</span>();
} <span class="kw">else</span> <span class="kw">if</span> <span class="ident">idle_state</span>.<span class="ident">rounds</span> <span class="op"><</span> <span class="ident">ROUNDS_UNTIL_SLEEPING</span> {
<span class="ident">idle_state</span>.<span class="ident">rounds</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
<span class="ident">thread::yield_now</span>();
} <span class="kw">else</span> {
<span class="macro">debug_assert_eq!</span>(<span class="ident">idle_state</span>.<span class="ident">rounds</span>, <span class="ident">ROUNDS_UNTIL_SLEEPING</span>);
<span class="self">self</span>.<span class="ident">sleep</span>(<span class="ident">idle_state</span>, <span class="ident">latch</span>, <span class="ident">has_injected_jobs</span>);
}
}
<span class="attribute">#[<span class="ident">cold</span>]</span>
<span class="kw">fn</span> <span class="ident">announce_sleepy</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">worker_index</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">></span> <span class="ident">JobsEventCounter</span> {
<span class="kw">let</span> <span class="ident">counters</span> <span class="op">=</span> <span class="self">self</span>
.<span class="ident">counters</span>
.<span class="ident">increment_jobs_event_counter_if</span>(<span class="ident">JobsEventCounter::is_active</span>);
<span class="kw">let</span> <span class="ident">jobs_counter</span> <span class="op">=</span> <span class="ident">counters</span>.<span class="ident">jobs_counter</span>();
<span class="self">self</span>.<span class="ident">logger</span>.<span class="ident">log</span>(<span class="op">|</span><span class="op">|</span> <span class="ident">ThreadSleepy</span> {
<span class="ident">worker</span>: <span class="ident">worker_index</span>,
<span class="ident">jobs_counter</span>: <span class="ident">jobs_counter</span>.<span class="ident">as_usize</span>(),
});
<span class="ident">jobs_counter</span>
}
<span class="attribute">#[<span class="ident">cold</span>]</span>
<span class="kw">fn</span> <span class="ident">sleep</span>(
<span class="kw-2">&</span><span class="self">self</span>,
<span class="ident">idle_state</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">IdleState</span>,
<span class="ident">latch</span>: <span class="kw-2">&</span><span class="ident">CoreLatch</span>,
<span class="ident">has_injected_jobs</span>: <span class="kw">impl</span> <span class="ident">FnOnce</span>() <span class="op">-</span><span class="op">></span> <span class="ident">bool</span>,
) {
<span class="kw">let</span> <span class="ident">worker_index</span> <span class="op">=</span> <span class="ident">idle_state</span>.<span class="ident">worker_index</span>;
<span class="kw">if</span> <span class="op">!</span><span class="ident">latch</span>.<span class="ident">get_sleepy</span>() {
<span class="self">self</span>.<span class="ident">logger</span>.<span class="ident">log</span>(<span class="op">|</span><span class="op">|</span> <span class="ident">ThreadSleepInterruptedByLatch</span> {
<span class="ident">worker</span>: <span class="ident">worker_index</span>,
<span class="ident">latch_addr</span>: <span class="ident">latch</span>.<span class="ident">addr</span>(),
});
<span class="kw">return</span>;
}
<span class="kw">let</span> <span class="ident">sleep_state</span> <span class="op">=</span> <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">worker_sleep_states</span>[<span class="ident">worker_index</span>];
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">is_blocked</span> <span class="op">=</span> <span class="ident">sleep_state</span>.<span class="ident">is_blocked</span>.<span class="ident">lock</span>().<span class="ident">unwrap</span>();
<span class="macro">debug_assert!</span>(<span class="op">!</span><span class="kw-2">*</span><span class="ident">is_blocked</span>);
<span class="comment">// Our latch was signalled. We should wake back up fully as we</span>
<span class="comment">// wil have some stuff to do.</span>
<span class="kw">if</span> <span class="op">!</span><span class="ident">latch</span>.<span class="ident">fall_asleep</span>() {
<span class="self">self</span>.<span class="ident">logger</span>.<span class="ident">log</span>(<span class="op">|</span><span class="op">|</span> <span class="ident">ThreadSleepInterruptedByLatch</span> {
<span class="ident">worker</span>: <span class="ident">worker_index</span>,
<span class="ident">latch_addr</span>: <span class="ident">latch</span>.<span class="ident">addr</span>(),
});
<span class="ident">idle_state</span>.<span class="ident">wake_fully</span>();
<span class="kw">return</span>;
}
<span class="kw">loop</span> {
<span class="kw">let</span> <span class="ident">counters</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">counters</span>.<span class="ident">load</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="comment">// Check if the JEC has changed since we got sleepy.</span>
<span class="macro">debug_assert!</span>(<span class="ident">idle_state</span>.<span class="ident">jobs_counter</span>.<span class="ident">is_sleepy</span>());
<span class="kw">if</span> <span class="ident">counters</span>.<span class="ident">jobs_counter</span>() <span class="op">!</span><span class="op">=</span> <span class="ident">idle_state</span>.<span class="ident">jobs_counter</span> {
<span class="comment">// JEC has changed, so a new job was posted, but for some reason</span>
<span class="comment">// we didn't see it. We should return to just before the SLEEPY</span>
<span class="comment">// state so we can do another search and (if we fail to find</span>
<span class="comment">// work) go back to sleep.</span>
<span class="self">self</span>.<span class="ident">logger</span>.<span class="ident">log</span>(<span class="op">|</span><span class="op">|</span> <span class="ident">ThreadSleepInterruptedByJob</span> {
<span class="ident">worker</span>: <span class="ident">worker_index</span>,
});
<span class="ident">idle_state</span>.<span class="ident">wake_partly</span>();
<span class="ident">latch</span>.<span class="ident">wake_up</span>();
<span class="kw">return</span>;
}
<span class="comment">// Otherwise, let's move from IDLE to SLEEPING.</span>
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">counters</span>.<span class="ident">try_add_sleeping_thread</span>(<span class="ident">counters</span>) {
<span class="kw">break</span>;
}
}
<span class="comment">// Successfully registered as asleep.</span>
<span class="self">self</span>.<span class="ident">logger</span>.<span class="ident">log</span>(<span class="op">|</span><span class="op">|</span> <span class="ident">ThreadSleeping</span> {
<span class="ident">worker</span>: <span class="ident">worker_index</span>,
<span class="ident">latch_addr</span>: <span class="ident">latch</span>.<span class="ident">addr</span>(),
});
<span class="comment">// We have one last check for injected jobs to do. This protects against</span>
<span class="comment">// deadlock in the very unlikely event that</span>
<span class="comment">//</span>
<span class="comment">// - an external job is being injected while we are sleepy</span>
<span class="comment">// - that job triggers the rollover over the JEC such that we don't see it</span>
<span class="comment">// - we are the last active worker thread</span>
<span class="ident">std::sync::atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="kw">if</span> <span class="ident">has_injected_jobs</span>() {
<span class="comment">// If we see an externally injected job, then we have to 'wake</span>
<span class="comment">// ourselves up'. (Ordinarily, `sub_sleeping_thread` is invoked by</span>
<span class="comment">// the one that wakes us.)</span>
<span class="self">self</span>.<span class="ident">counters</span>.<span class="ident">sub_sleeping_thread</span>();
} <span class="kw">else</span> {
<span class="comment">// If we don't see an injected job (the normal case), then flag</span>
<span class="comment">// ourselves as asleep and wait till we are notified.</span>
<span class="comment">//</span>
<span class="comment">// (Note that `is_blocked` is held under a mutex and the mutex was</span>
<span class="comment">// acquired *before* we incremented the "sleepy counter". This means</span>
<span class="comment">// that whomever is coming to wake us will have to wait until we</span>
<span class="comment">// release the mutex in the call to `wait`, so they will see this</span>
<span class="comment">// boolean as true.)</span>
<span class="kw-2">*</span><span class="ident">is_blocked</span> <span class="op">=</span> <span class="bool-val">true</span>;
<span class="kw">while</span> <span class="kw-2">*</span><span class="ident">is_blocked</span> {
<span class="ident">is_blocked</span> <span class="op">=</span> <span class="ident">sleep_state</span>.<span class="ident">condvar</span>.<span class="ident">wait</span>(<span class="ident">is_blocked</span>).<span class="ident">unwrap</span>();
}
}
<span class="comment">// Update other state:</span>
<span class="ident">idle_state</span>.<span class="ident">wake_fully</span>();
<span class="ident">latch</span>.<span class="ident">wake_up</span>();
<span class="self">self</span>.<span class="ident">logger</span>.<span class="ident">log</span>(<span class="op">|</span><span class="op">|</span> <span class="ident">ThreadAwoken</span> {
<span class="ident">worker</span>: <span class="ident">worker_index</span>,
<span class="ident">latch_addr</span>: <span class="ident">latch</span>.<span class="ident">addr</span>(),
});
}
<span class="doccomment">/// Notify the given thread that it should wake up (if it is</span>
<span class="doccomment">/// sleeping). When this method is invoked, we typically know the</span>
<span class="doccomment">/// thread is asleep, though in rare cases it could have been</span>
<span class="doccomment">/// awoken by (e.g.) new work having been posted.</span>
<span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn</span> <span class="ident">notify_worker_latch_is_set</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">target_worker_index</span>: <span class="ident">usize</span>) {
<span class="self">self</span>.<span class="ident">wake_specific_thread</span>(<span class="ident">target_worker_index</span>);
}
<span class="doccomment">/// Signals that `num_jobs` new jobs were injected into the thread</span>
<span class="doccomment">/// pool from outside. This function will ensure that there are</span>
<span class="doccomment">/// threads available to process them, waking threads from sleep</span>
<span class="doccomment">/// if necessary.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Parameters</span>
<span class="doccomment">///</span>
<span class="doccomment">/// - `source_worker_index` -- index of the thread that did the</span>
<span class="doccomment">/// push, or `usize::MAX` if this came from outside the thread</span>
<span class="doccomment">/// pool -- it is used only for logging.</span>
<span class="doccomment">/// - `num_jobs` -- lower bound on number of jobs available for stealing.</span>
<span class="doccomment">/// We'll try to get at least one thread per job.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn</span> <span class="ident">new_injected_jobs</span>(
<span class="kw-2">&</span><span class="self">self</span>,
<span class="ident">source_worker_index</span>: <span class="ident">usize</span>,
<span class="ident">num_jobs</span>: <span class="ident">u32</span>,
<span class="ident">queue_was_empty</span>: <span class="ident">bool</span>,
) {
<span class="comment">// This fence is needed to guarantee that threads</span>
<span class="comment">// as they are about to fall asleep, observe any</span>
<span class="comment">// new jobs that may have been injected.</span>
<span class="ident">std::sync::atomic::fence</span>(<span class="ident">Ordering::SeqCst</span>);
<span class="self">self</span>.<span class="ident">new_jobs</span>(<span class="ident">source_worker_index</span>, <span class="ident">num_jobs</span>, <span class="ident">queue_was_empty</span>)
}
<span class="doccomment">/// Signals that `num_jobs` new jobs were pushed onto a thread's</span>
<span class="doccomment">/// local deque. This function will try to ensure that there are</span>
<span class="doccomment">/// threads available to process them, waking threads from sleep</span>
<span class="doccomment">/// if necessary. However, this is not guaranteed: under certain</span>
<span class="doccomment">/// race conditions, the function may fail to wake any new</span>
<span class="doccomment">/// threads; in that case the existing thread should eventually</span>
<span class="doccomment">/// pop the job.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Parameters</span>
<span class="doccomment">///</span>
<span class="doccomment">/// - `source_worker_index` -- index of the thread that did the</span>
<span class="doccomment">/// push, or `usize::MAX` if this came from outside the thread</span>
<span class="doccomment">/// pool -- it is used only for logging.</span>
<span class="doccomment">/// - `num_jobs` -- lower bound on number of jobs available for stealing.</span>
<span class="doccomment">/// We'll try to get at least one thread per job.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn</span> <span class="ident">new_internal_jobs</span>(
<span class="kw-2">&</span><span class="self">self</span>,
<span class="ident">source_worker_index</span>: <span class="ident">usize</span>,
<span class="ident">num_jobs</span>: <span class="ident">u32</span>,
<span class="ident">queue_was_empty</span>: <span class="ident">bool</span>,
) {
<span class="self">self</span>.<span class="ident">new_jobs</span>(<span class="ident">source_worker_index</span>, <span class="ident">num_jobs</span>, <span class="ident">queue_was_empty</span>)
}
<span class="doccomment">/// Common helper for `new_injected_jobs` and `new_internal_jobs`.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">new_jobs</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">source_worker_index</span>: <span class="ident">usize</span>, <span class="ident">num_jobs</span>: <span class="ident">u32</span>, <span class="ident">queue_was_empty</span>: <span class="ident">bool</span>) {
<span class="comment">// Read the counters and -- if sleepy workers have announced themselves</span>
<span class="comment">// -- announce that there is now work available. The final value of `counters`</span>
<span class="comment">// with which we exit the loop thus corresponds to a state when</span>
<span class="kw">let</span> <span class="ident">counters</span> <span class="op">=</span> <span class="self">self</span>
.<span class="ident">counters</span>
.<span class="ident">increment_jobs_event_counter_if</span>(<span class="ident">JobsEventCounter::is_sleepy</span>);
<span class="kw">let</span> <span class="ident">num_awake_but_idle</span> <span class="op">=</span> <span class="ident">counters</span>.<span class="ident">awake_but_idle_threads</span>();
<span class="kw">let</span> <span class="ident">num_sleepers</span> <span class="op">=</span> <span class="ident">counters</span>.<span class="ident">sleeping_threads</span>();
<span class="self">self</span>.<span class="ident">logger</span>.<span class="ident">log</span>(<span class="op">|</span><span class="op">|</span> <span class="ident">JobThreadCounts</span> {
<span class="ident">worker</span>: <span class="ident">source_worker_index</span>,
<span class="ident">num_idle</span>: <span class="ident">num_awake_but_idle</span> <span class="kw">as</span> <span class="ident">u16</span>,
<span class="ident">num_sleepers</span>: <span class="ident">num_sleepers</span> <span class="kw">as</span> <span class="ident">u16</span>,
});
<span class="kw">if</span> <span class="ident">num_sleepers</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="comment">// nobody to wake</span>
<span class="kw">return</span>;
}
<span class="comment">// Promote from u16 to u32 so we can interoperate with</span>
<span class="comment">// num_jobs more easily.</span>
<span class="kw">let</span> <span class="ident">num_awake_but_idle</span> <span class="op">=</span> <span class="ident">num_awake_but_idle</span> <span class="kw">as</span> <span class="ident">u32</span>;
<span class="kw">let</span> <span class="ident">num_sleepers</span> <span class="op">=</span> <span class="ident">num_sleepers</span> <span class="kw">as</span> <span class="ident">u32</span>;
<span class="comment">// If the queue is non-empty, then we always wake up a worker</span>
<span class="comment">// -- clearly the existing idle jobs aren't enough. Otherwise,</span>
<span class="comment">// check to see if we have enough idle workers.</span>
<span class="kw">if</span> <span class="op">!</span><span class="ident">queue_was_empty</span> {
<span class="kw">let</span> <span class="ident">num_to_wake</span> <span class="op">=</span> <span class="ident">std::cmp::min</span>(<span class="ident">num_jobs</span>, <span class="ident">num_sleepers</span>);
<span class="self">self</span>.<span class="ident">wake_any_threads</span>(<span class="ident">num_to_wake</span>);
} <span class="kw">else</span> <span class="kw">if</span> <span class="ident">num_awake_but_idle</span> <span class="op"><</span> <span class="ident">num_jobs</span> {
<span class="kw">let</span> <span class="ident">num_to_wake</span> <span class="op">=</span> <span class="ident">std::cmp::min</span>(<span class="ident">num_jobs</span> <span class="op">-</span> <span class="ident">num_awake_but_idle</span>, <span class="ident">num_sleepers</span>);
<span class="self">self</span>.<span class="ident">wake_any_threads</span>(<span class="ident">num_to_wake</span>);
}
}
<span class="attribute">#[<span class="ident">cold</span>]</span>
<span class="kw">fn</span> <span class="ident">wake_any_threads</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="kw-2">mut</span> <span class="ident">num_to_wake</span>: <span class="ident">u32</span>) {
<span class="kw">if</span> <span class="ident">num_to_wake</span> <span class="op">></span> <span class="number">0</span> {
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="self">self</span>.<span class="ident">worker_sleep_states</span>.<span class="ident">len</span>() {
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">wake_specific_thread</span>(<span class="ident">i</span>) {
<span class="ident">num_to_wake</span> <span class="op">-</span><span class="op">=</span> <span class="number">1</span>;
<span class="kw">if</span> <span class="ident">num_to_wake</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="kw">return</span>;
}
}
}
}
}
<span class="kw">fn</span> <span class="ident">wake_specific_thread</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">index</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
<span class="kw">let</span> <span class="ident">sleep_state</span> <span class="op">=</span> <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">worker_sleep_states</span>[<span class="ident">index</span>];
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">is_blocked</span> <span class="op">=</span> <span class="ident">sleep_state</span>.<span class="ident">is_blocked</span>.<span class="ident">lock</span>().<span class="ident">unwrap</span>();
<span class="kw">if</span> <span class="kw-2">*</span><span class="ident">is_blocked</span> {
<span class="kw-2">*</span><span class="ident">is_blocked</span> <span class="op">=</span> <span class="bool-val">false</span>;
<span class="ident">sleep_state</span>.<span class="ident">condvar</span>.<span class="ident">notify_one</span>();
<span class="comment">// When the thread went to sleep, it will have incremented</span>
<span class="comment">// this value. When we wake it, its our job to decrement</span>
<span class="comment">// it. We could have the thread do it, but that would</span>
<span class="comment">// introduce a delay between when the thread was</span>
<span class="comment">// *notified* and when this counter was decremented. That</span>
<span class="comment">// might mislead people with new work into thinking that</span>
<span class="comment">// there are sleeping threads that they should try to</span>
<span class="comment">// wake, when in fact there is nothing left for them to</span>
<span class="comment">// do.</span>
<span class="self">self</span>.<span class="ident">counters</span>.<span class="ident">sub_sleeping_thread</span>();
<span class="self">self</span>.<span class="ident">logger</span>.<span class="ident">log</span>(<span class="op">|</span><span class="op">|</span> <span class="ident">ThreadNotify</span> { <span class="ident">worker</span>: <span class="ident">index</span> });
<span class="bool-val">true</span>
} <span class="kw">else</span> {
<span class="bool-val">false</span>
}
}
}
<span class="kw">impl</span> <span class="ident">IdleState</span> {
<span class="kw">fn</span> <span class="ident">wake_fully</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="self">self</span>.<span class="ident">rounds</span> <span class="op">=</span> <span class="number">0</span>;
<span class="self">self</span>.<span class="ident">jobs_counter</span> <span class="op">=</span> <span class="ident">JobsEventCounter::DUMMY</span>;
}
<span class="kw">fn</span> <span class="ident">wake_partly</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="self">self</span>.<span class="ident">rounds</span> <span class="op">=</span> <span class="ident">ROUNDS_UNTIL_SLEEPY</span>;
<span class="self">self</span>.<span class="ident">jobs_counter</span> <span class="op">=</span> <span class="ident">JobsEventCounter::DUMMY</span>;
}
}
</pre></div>
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