| Flutter Impeller |

gpu_tracer_vk.cc
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1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "impeller/renderer/backend/vulkan/gpu_tracer_vk.h"
6
7 #include <memory>
8 #include <optional>
9 #include <thread>
10 #include <utility>
11
12 #include "fml/logging.h"
13 #include "fml/trace_event.h"
14 #include "impeller/base/validation.h"
15 #include "impeller/renderer/backend/vulkan/command_buffer_vk.h"
16 #include "impeller/renderer/backend/vulkan/context_vk.h"
17
18 namespace impeller {
19
20 static constexpr uint32_t kPoolSize = 128u;
21
22 GPUTracerVK::GPUTracerVK(std::weak_ptr<ContextVK> context,
23 bool enable_gpu_tracing)
24 : context_(std::move(context)) {
25 if (!enable_gpu_tracing) {
26 return;
27 }
28 timestamp_period_ = context_.lock()
29 ->GetDeviceHolder()
30 ->GetPhysicalDevice()
31 .getProperties()
32 .limits.timestampPeriod;
33 if (timestamp_period_ <= 0) {
34 // The device does not support timestamp queries.
35 return;
36 }
37 // Disable tracing in release mode.
38 #ifdef IMPELLER_DEBUG
39 enabled_ = true;
40 #endif // IMPELLER_DEBUG
41 }
42
43 void GPUTracerVK::InitializeQueryPool(const ContextVK& context) {
44 if (!enabled_) {
45 return;
46 }
47 Lock lock(trace_state_mutex_);
48 std::shared_ptr<CommandBuffer> buffer = context.CreateCommandBuffer();
49 CommandBufferVK& buffer_vk = CommandBufferVK::Cast(*buffer);
50
51 for (auto i = 0u; i < kTraceStatesSize; i++) {
52 vk::QueryPoolCreateInfo info;
53 info.queryCount = kPoolSize;
54 info.queryType = vk::QueryType::eTimestamp;
55
56 auto [status, pool] = context.GetDevice().createQueryPoolUnique(info);
57 if (status != vk::Result::eSuccess) {
58 VALIDATION_LOG << "Failed to create query pool.";
59 return;
60 }
61 trace_states_[i].query_pool = std::move(pool);
62 buffer_vk.GetCommandBuffer().resetQueryPool(
63 trace_states_[i].query_pool.get(), 0, kPoolSize);
64 }
65 if (!context.GetCommandQueue()->Submit({buffer}).ok()) {
66 VALIDATION_LOG << "Failed to reset query pool for trace events.";
67 enabled_ = false;
68 }
69 }
70
71 bool GPUTracerVK::IsEnabled() const {
72 return enabled_;
73 }
74
75 void GPUTracerVK::MarkFrameStart() {
76 if (!enabled_) {
77 return;
78 }
79 FML_DCHECK(!in_frame_);
80 in_frame_ = true;
81 raster_thread_id_ = std::this_thread::get_id();
82 }
83
84 void GPUTracerVK::MarkFrameEnd() {
85 in_frame_ = false;
86
87 if (!enabled_) {
88 return;
89 }
90
91 Lock lock(trace_state_mutex_);
92 current_state_ = (current_state_ + 1) % kTraceStatesSize;
93
94 auto& state = trace_states_[current_state_];
95 // If there are still pending buffers on the trace state we're switching to,
96 // that means that a cmd buffer we were relying on to signal this likely
97 // never finished. This shouldn't happen unless there is a bug in the
98 // encoder logic. We set it to zero anyway to prevent a validation error
99 // from becoming a memory leak.
100 FML_DCHECK(state.pending_buffers == 0u);
101 state.pending_buffers = 0;
102 state.current_index = 0;
103 }
104
105 std::unique_ptr<GPUProbe> GPUTracerVK::CreateGPUProbe() {
106 return std::make_unique<GPUProbe>(weak_from_this());
107 }
108
109 void GPUTracerVK::RecordCmdBufferStart(const vk::CommandBuffer& buffer,
110 GPUProbe& probe) {
111 if (!enabled_ || std::this_thread::get_id() != raster_thread_id_ ||
112 !in_frame_) {
113 return;
114 }
115 Lock lock(trace_state_mutex_);
116 auto& state = trace_states_[current_state_];
117
118 // Reset previously completed queries.
119 if (!states_to_reset_.empty()) {
120 for (auto i = 0u; i < states_to_reset_.size(); i++) {
121 buffer.resetQueryPool(trace_states_[states_to_reset_[i]].query_pool.get(),
122 0, kPoolSize);
123 }
124 states_to_reset_.clear();
125 }
126
127 // We size the query pool to kPoolSize, but Flutter applications can create an
128 // unbounded amount of work per frame. If we encounter this, stop recording
129 // cmds.
130 if (state.current_index >= kPoolSize) {
131 return;
132 }
133
134 buffer.writeTimestamp(vk::PipelineStageFlagBits::eTopOfPipe,
135 trace_states_[current_state_].query_pool.get(),
136 state.current_index);
137 state.current_index += 1;
138 probe.index_ = current_state_;
139 state.pending_buffers += 1;
140 }
141
142 void GPUTracerVK::RecordCmdBufferEnd(const vk::CommandBuffer& buffer,
143 GPUProbe& probe) {
144 if (!enabled_ || std::this_thread::get_id() != raster_thread_id_ ||
145 !in_frame_ || !probe.index_.has_value()) {
146 return;
147 }
148 Lock lock(trace_state_mutex_);
149 GPUTraceState& state = trace_states_[current_state_];
150
151 if (state.current_index >= kPoolSize) {
152 return;
153 }
154
155 buffer.writeTimestamp(vk::PipelineStageFlagBits::eBottomOfPipe,
156 state.query_pool.get(), state.current_index);
157
158 state.current_index += 1;
159 }
160
161 void GPUTracerVK::OnFenceComplete(size_t frame_index) {
162 if (!enabled_) {
163 return;
164 }
165
166 size_t pending = 0;
167 size_t query_count = 0;
168 vk::QueryPool pool;
169 {
170 Lock lock(trace_state_mutex_);
171 GPUTraceState& state = trace_states_[frame_index];
172
173 FML_DCHECK(state.pending_buffers > 0);
174 state.pending_buffers -= 1;
175 pending = state.pending_buffers;
176 query_count = state.current_index;
177 pool = state.query_pool.get();
178 }
179
180 if (pending == 0) {
181 std::vector<uint64_t> bits(query_count);
182 std::shared_ptr<ContextVK> context = context_.lock();
183 if (!context) {
184 return;
185 }
186
187 auto result = context->GetDevice().getQueryPoolResults(
188 pool, 0, query_count, query_count * sizeof(uint64_t), bits.data(),
189 sizeof(uint64_t), vk::QueryResultFlagBits::e64);
190 // This may return VK_NOT_READY if the query couldn't be completed, or if
191 // there are queries still pending. From local testing, this happens
192 // occassionally on very expensive frames. Its unclear if we can do anything
193 // about this, because by design this should only signal after all cmd
194 // buffers have signaled. Adding VK_QUERY_RESULT_WAIT_BIT to the flags
195 // passed to getQueryPoolResults seems like it would fix this, but actually
196 // seems to result in more stuck query errors. Better to just drop them and
197 // move on.
198 if (result == vk::Result::eSuccess) {
199 uint64_t smallest_timestamp = std::numeric_limits<uint64_t>::max();
200 uint64_t largest_timestamp = 0;
201 for (auto i = 0u; i < bits.size(); i++) {
202 smallest_timestamp = std::min(smallest_timestamp, bits[i]);
203 largest_timestamp = std::max(largest_timestamp, bits[i]);
204 }
205 auto gpu_ms =
206 (((largest_timestamp - smallest_timestamp) * timestamp_period_) /
207 1000000);
208 FML_TRACE_COUNTER("flutter", "GPUTracer",
209 reinterpret_cast<int64_t>(this), // Trace Counter ID
210 "FrameTimeMS", gpu_ms);
211 }
212
213 // Record this query to be reset the next time a command is recorded.
214 Lock lock(trace_state_mutex_);
215 states_to_reset_.push_back(frame_index);
216 }
217 }
218
219 GPUProbe::GPUProbe(const std::weak_ptr<GPUTracerVK>& tracer)
220 : tracer_(tracer) {}
221
222 GPUProbe::~GPUProbe() {
223 if (!index_.has_value()) {
224 return;
225 }
226 auto tracer = tracer_.lock();
227 if (!tracer) {
228 return;
229 }
230 tracer->OnFenceComplete(index_.value());
231 }
232
233 void GPUProbe::RecordCmdBufferStart(const vk::CommandBuffer& buffer) {
234 auto tracer = tracer_.lock();
235 if (!tracer) {
236 return;
237 }
238 tracer->RecordCmdBufferStart(buffer, *this);
239 }
240
241 void GPUProbe::RecordCmdBufferEnd(const vk::CommandBuffer& buffer) {
242 auto tracer = tracer_.lock();
243 if (!tracer) {
244 return;
245 }
246 tracer->RecordCmdBufferEnd(buffer, *this);
247 }
248
249 } // namespace impeller
impeller::BackendCast< CommandBufferVK, CommandBuffer >::Cast
static CommandBufferVK & Cast(CommandBuffer &base)
Definition: backend_cast.h:13
impeller::CommandBufferVK
Definition: command_buffer_vk.h:27
impeller::CommandBufferVK::GetCommandBuffer
vk::CommandBuffer GetCommandBuffer() const
Retrieve the native command buffer from this object.
Definition: command_buffer_vk.cc:120
impeller::ContextVK
Definition: context_vk.h:66
impeller::ContextVK::GetDevice
const vk::Device & GetDevice() const
Definition: context_vk.cc:589
impeller::ContextVK::CreateCommandBuffer
std::shared_ptr< CommandBuffer > CreateCommandBuffer() const override
Create a new command buffer. Command buffers can be used to encode graphics, blit,...
Definition: context_vk.cc:536
impeller::ContextVK::GetCommandQueue
std::shared_ptr< CommandQueue > GetCommandQueue() const override
Return the graphics queue for submitting command buffers.
Definition: context_vk.cc:648
impeller::GPUProbe
Definition: gpu_tracer_vk.h:101
impeller::GPUProbe::RecordCmdBufferStart
void RecordCmdBufferStart(const vk::CommandBuffer &buffer)
Record a timestamp query into the provided cmd buffer to record start time.
Definition: gpu_tracer_vk.cc:233
impeller::GPUProbe::GPUProbe
GPUProbe(const std::weak_ptr< GPUTracerVK > &tracer)
Definition: gpu_tracer_vk.cc:219
impeller::GPUProbe::~GPUProbe
~GPUProbe()
Definition: gpu_tracer_vk.cc:222
impeller::GPUProbe::RecordCmdBufferEnd
void RecordCmdBufferEnd(const vk::CommandBuffer &buffer)
Record a timestamp query into the provided cmd buffer to record end time.
Definition: gpu_tracer_vk.cc:241
impeller::GPUTracerVK::MarkFrameStart
void MarkFrameStart()
Signal the start of a frame workload.
Definition: gpu_tracer_vk.cc:75
impeller::GPUTracerVK::MarkFrameEnd
void MarkFrameEnd()
Signal the end of a frame workload.
Definition: gpu_tracer_vk.cc:84
impeller::GPUTracerVK::CreateGPUProbe
std::unique_ptr< GPUProbe > CreateGPUProbe()
Create a GPUProbe to trace the execution of a command buffer on the GPU.
Definition: gpu_tracer_vk.cc:105
impeller::GPUTracerVK::InitializeQueryPool
void InitializeQueryPool(const ContextVK &context)
Initialize the set of query pools.
Definition: gpu_tracer_vk.cc:43
impeller::GPUTracerVK::GPUTracerVK
GPUTracerVK(std::weak_ptr< ContextVK > context, bool enable_gpu_tracing)
Definition: gpu_tracer_vk.cc:22
impeller::GPUTracerVK::IsEnabled
bool IsEnabled() const
Definition: gpu_tracer_vk.cc:71
impeller::Lock
Definition: thread.h:72
command_buffer_vk.h
gpu_tracer_vk.h
impeller
Definition: allocation.cc:12
impeller::kPoolSize
static constexpr uint32_t kPoolSize
Definition: gpu_tracer_vk.cc:20
std
Definition: comparable.h:95
context_vk.h
validation.h
VALIDATION_LOG
#define VALIDATION_LOG
Definition: validation.h:91