1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
#include "swapchain_monitor.hh"
#include "device_context.hh"
#include "helper.hh"
#include <vulkan/vulkan_core.h>
#include <functional>
#include <mutex>
namespace low_latency {
SwapchainMonitor::SwapchainMonitor(const DeviceContext& device,
const bool was_low_latency_requested)
: device(device), was_low_latency_requested(was_low_latency_requested) {}
SwapchainMonitor::~SwapchainMonitor() {}
void SwapchainMonitor::update_params(
const bool was_low_latency_requested,
const std::chrono::milliseconds present_delay) {
this->was_low_latency_requested = was_low_latency_requested;
this->present_delay = present_delay;
}
void SwapchainMonitor::prune_submissions() {
// If our submissions grow too large, we should delete them from our
// tracking. It would be nice if this was handled elegantly by some custom
// container and we didn't have to call this manually each time we insert.
// Also this exact logic is repeated in QueueContext's Submission.
if (std::size(this->in_flight_submissions) >
this->MAX_TRACKED_IN_FLIGHT_SUBMISSIONS) {
this->in_flight_submissions.pop_front();
}
}
ReflexSwapchainMonitor::ReflexSwapchainMonitor(
const DeviceContext& device, const bool was_low_latency_requested)
: SwapchainMonitor(device, was_low_latency_requested),
monitor_worker(
std::bind_front(&ReflexSwapchainMonitor::do_monitor, this)) {}
ReflexSwapchainMonitor::~ReflexSwapchainMonitor() {}
void ReflexSwapchainMonitor::WakeupSemaphore::signal(
const DeviceContext& device) const {
const auto ssi =
VkSemaphoreSignalInfo{.sType = VK_STRUCTURE_TYPE_SEMAPHORE_SIGNAL_INFO,
.semaphore = this->timeline_semaphore,
.value = this->value};
THROW_NOT_VKSUCCESS(device.vtable.SignalSemaphore(device.device, &ssi));
}
void ReflexSwapchainMonitor::do_monitor(const std::stop_token stoken) {
for (;;) {
auto lock = std::unique_lock{this->mutex};
this->cv.wait(lock, stoken,
[&]() { return !this->wakeup_semaphores.empty(); });
if (stoken.stop_requested()) {
// Small chance an application might need outstanding semaphores
// to be signalled if it's closing to avoid a hang.
break;
}
// Look for the latest submission and make sure it's completed.
if (!this->in_flight_submissions.empty()) {
this->in_flight_submissions.back()->await_completed();
this->in_flight_submissions.clear();
}
// We might want to signal them all? In theory it's the same timeline
// semaphore so obviously it's redundant to signal them one by one. In
// almost all cases, there should just be one here anyway.
const auto wakeup_semaphore = this->wakeup_semaphores.back();
wakeup_semaphores.clear();
wakeup_semaphore.signal(this->device);
}
}
void ReflexSwapchainMonitor::notify_semaphore(
const VkSemaphore& timeline_semaphore, const std::uint64_t& value) {
const auto lock = std::scoped_lock{this->mutex};
const auto wakeup_semaphore = WakeupSemaphore{
.timeline_semaphore = timeline_semaphore, .value = value};
// Signal immediately if low_latency isn't requested or if we have no
// outstanding work.
if (!this->was_low_latency_requested ||
this->in_flight_submissions.empty()) {
wakeup_semaphore.signal(this->device);
return;
}
this->wakeup_semaphores.emplace_back(timeline_semaphore, value);
this->cv.notify_one();
}
void ReflexSwapchainMonitor::notify_present(
std::unique_ptr<QueueContext::Submissions> submissions) {
const auto lock = std::scoped_lock{this->mutex};
if (!this->was_low_latency_requested) {
return;
}
// Fast path where this work has already completed.
// In this case, don't wake up the thread. We can just signal
// what we have immediately on this thread.
if (!this->wakeup_semaphores.empty() && submissions->has_completed()) {
this->wakeup_semaphores.back().signal(this->device);
this->wakeup_semaphores.clear();
return;
}
this->in_flight_submissions.emplace_back(std::move(submissions));
this->prune_submissions();
this->cv.notify_one();
}
AntiLagSwapchainMonitor::AntiLagSwapchainMonitor(
const DeviceContext& device, const bool was_low_latency_requested)
: SwapchainMonitor(device, was_low_latency_requested) {}
AntiLagSwapchainMonitor::~AntiLagSwapchainMonitor() {}
void AntiLagSwapchainMonitor::notify_present(
std::unique_ptr<QueueContext::Submissions> submissions) {
if (!this->was_low_latency_requested) {
return;
}
this->in_flight_submissions.emplace_back(std::move(submissions));
this->prune_submissions();
}
void AntiLagSwapchainMonitor::await_submissions() {
if (this->in_flight_submissions.empty()) {
return;
}
this->in_flight_submissions.back()->await_completed();
this->in_flight_submissions.clear();
}
} // namespace low_latency
|
