ea2bd42ff4
By default, the memory order on atomics is `seq_cst`. This is a relatively expensive ordering and it shows in situations where we're rapidly signaling a consumer to pick up something from a producer. I've instead attempted to switch these to `release` (producer) and `acquire` (consumer) to improve the performance of these signals. ## Validation Steps Performed - Run `time cat big.txt` and `time cat ls.txt` under VS Performance Profiler. ## PR Checklist * [x] Closes perf itch * [x] I work here * [x] Manual test * [x] Documentation irrelevant. * [x] Schema irrelevant. * [x] Am core contributor.
55 lines
1.5 KiB
C++
55 lines
1.5 KiB
C++
// Copyright (c) Microsoft Corporation.
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// Licensed under the MIT license.
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#include "pch.h"
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#include "ThrottledFunc.h"
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using namespace winrt::Windows::Foundation;
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using namespace winrt::Windows::UI::Core;
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using namespace winrt::Windows::UI::Xaml;
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ThrottledFunc<>::ThrottledFunc(ThrottledFunc::Func func, TimeSpan delay, CoreDispatcher dispatcher) :
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_func{ func },
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_delay{ delay },
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_dispatcher{ dispatcher },
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_isRunPending{}
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{
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}
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// Method Description:
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// - Runs the function later, except if `Run` is called again before
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// with a new argument, in which case the request will be ignored.
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// - For more information, read the class' documentation.
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// - This method is always thread-safe. It can be called multiple times on
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// different threads.
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// Arguments:
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// - <none>
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// Return Value:
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// - <none>
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void ThrottledFunc<>::Run()
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{
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if (_isRunPending.test_and_set(std::memory_order_acquire))
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{
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// already pending
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return;
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}
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_dispatcher.RunAsync(CoreDispatcherPriority::Low, [weakThis = this->weak_from_this()]() {
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if (auto self{ weakThis.lock() })
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{
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DispatcherTimer timer;
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timer.Interval(self->_delay);
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timer.Tick([=](auto&&...) {
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if (auto self{ weakThis.lock() })
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{
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timer.Stop();
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self->_isRunPending.clear(std::memory_order_release);
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self->_func();
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}
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});
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timer.Start();
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}
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});
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}
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