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◆ main openmsx / src / RTScheduler.cc
1.6 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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#include "RTScheduler.hh"
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#include "RTSchedulable.hh"
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#include <algorithm>
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#include <limits>
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namespace openmsx {
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struct EqualRTSchedulable {
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	explicit EqualRTSchedulable(const RTSchedulable& schedulable_)
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		: schedulable(schedulable_) {}
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	bool operator()(const RTSyncPoint& sp) const {
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		return sp.schedulable == &schedulable;
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	}
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	const RTSchedulable& schedulable;
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};
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void RTScheduler::add(uint64_t delta, RTSchedulable& schedulable)
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{
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	queue.insert(RTSyncPoint{.time = Timer::getTime() + delta, .schedulable = &schedulable},
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	             [](RTSyncPoint& sp) {
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	                     sp.time = std::numeric_limits<uint64_t>::max(); },
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	             [](const RTSyncPoint& x, const RTSyncPoint& y) {
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	                     return x.time < y.time; });
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}
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bool RTScheduler::remove(RTSchedulable& schedulable)
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{
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	return queue.remove(EqualRTSchedulable(schedulable));
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}
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bool RTScheduler::isPending(const RTSchedulable& schedulable) const
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{
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	return std::ranges::any_of(queue, EqualRTSchedulable(schedulable));
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}
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void RTScheduler::scheduleHelper(uint64_t limit)
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{
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	// Process at most this many events to prevent getting stuck in an
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	// infinite loop when a RTSchedulable keeps on rescheduling itself in
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	// the (too) near future.
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	auto count = queue.size();
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	while (true) {
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		auto* schedulable = queue.front().schedulable;
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		queue.remove_front();
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		schedulable->executeRT();
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		// It's possible RTSchedulables are canceled in the mean time,
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		// so we can't rely on 'count' to replace this empty check.
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		if (queue.empty()) break;
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		if (queue.front().time > limit) [[likely]] break;
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		if (--count == 0) break;
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	}
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}
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} // namespace openmsx