impeller::GPUTracerVK Class Reference

A class that uses timestamp queries to record the approximate GPU execution time. More...

#include <gpu_tracer_vk.h>

Inheritance diagram for impeller::GPUTracerVK:

Public Member Functions
	GPUTracerVK (std::weak_ptr< ContextVK > context, bool enable_gpu_tracing)
	~GPUTracerVK ()=default
std::unique_ptr< GPUProbe >	CreateGPUProbe ()
	Create a GPUProbe to trace the execution of a command buffer on the GPU. More...
void	MarkFrameStart ()
	Signal the start of a frame workload. More...
void	MarkFrameEnd ()
	Signal the end of a frame workload. More...
bool	IsEnabled () const
void	InitializeQueryPool (const ContextVK &context)
	Initialize the set of query pools. More...

Friends
class	GPUProbe

Detailed Description

A class that uses timestamp queries to record the approximate GPU execution time.

To enable, add the following metadata to the application's Android manifest: <meta-data android:name="io.flutter.embedding.android.EnableVulkanGPUTracing" android:value="false" />

Definition at line 26 of file gpu_tracer_vk.h.

Constructor & Destructor Documentation

GPUTracerVK()

impeller::GPUTracerVK::GPUTracerVK	(	std::weak_ptr< ContextVK >	context,
		bool	enable_gpu_tracing
	)

Definition at line 22 of file gpu_tracer_vk.cc.

    : context_(std::move(context)) {
  if (!enable_gpu_tracing) {
    return;
  }
  timestamp_period_ = context_.lock()
                          ->GetDeviceHolder()
                          ->GetPhysicalDevice()
                          .getProperties()
                          .limits.timestampPeriod;
  if (timestamp_period_ <= 0) {
    // The device does not support timestamp queries.
    return;
  }
// Disable tracing in release mode.
#ifdef IMPELLER_DEBUG
  enabled_ = true;
#endif  // IMPELLER_DEBUG
}

~GPUTracerVK()

impeller::GPUTracerVK::~GPUTracerVK ( )

default

Member Function Documentation

CreateGPUProbe()

std::unique_ptr< GPUProbe > impeller::GPUTracerVK::CreateGPUProbe

(

)

Create a GPUProbe to trace the execution of a command buffer on the GPU.

Definition at line 105 of file gpu_tracer_vk.cc.

                                                    {
  return std::make_unique<GPUProbe>(weak_from_this());
}

InitializeQueryPool()

void impeller::GPUTracerVK::InitializeQueryPool

(

const ContextVK &

context

)

Initialize the set of query pools.

Definition at line 43 of file gpu_tracer_vk.cc.

                                                              {
  if (!enabled_) {
    return;
  }
  Lock lock(trace_state_mutex_);
  std::shared_ptr<CommandBuffer> buffer = context.CreateCommandBuffer();
  CommandBufferVK& buffer_vk = CommandBufferVK::Cast(*buffer);
 
  for (auto i = 0u; i < kTraceStatesSize; i++) {
    vk::QueryPoolCreateInfo info;
    info.queryCount = kPoolSize;
    info.queryType = vk::QueryType::eTimestamp;
 
    auto [status, pool] = context.GetDevice().createQueryPoolUnique(info);
    if (status != vk::Result::eSuccess) {
      VALIDATION_LOG << "Failed to create query pool.";
      return;
    }
    trace_states_[i].query_pool = std::move(pool);
    buffer_vk.GetCommandBuffer().resetQueryPool(
        trace_states_[i].query_pool.get(), 0, kPoolSize);
  }
  if (!context.GetCommandQueue()->Submit({buffer}).ok()) {
    VALIDATION_LOG << "Failed to reset query pool for trace events.";
    enabled_ = false;
  }
}

References impeller::BackendCast< CommandBufferVK, CommandBuffer >::Cast(), impeller::ContextVK::CreateCommandBuffer(), impeller::CommandBufferVK::GetCommandBuffer(), impeller::ContextVK::GetCommandQueue(), impeller::ContextVK::GetDevice(), impeller::kPoolSize, and VALIDATION_LOG.

IsEnabled()

bool impeller::GPUTracerVK::IsEnabled

(

)

const

Definition at line 71 of file gpu_tracer_vk.cc.

                                  {
  return enabled_;
}

MarkFrameEnd()

void impeller::GPUTracerVK::MarkFrameEnd

(

)

Signal the end of a frame workload.

Definition at line 84 of file gpu_tracer_vk.cc.

                               {
  in_frame_ = false;
 
  if (!enabled_) {
    return;
  }
 
  Lock lock(trace_state_mutex_);
  current_state_ = (current_state_ + 1) % kTraceStatesSize;
 
  auto& state = trace_states_[current_state_];
  // If there are still pending buffers on the trace state we're switching to,
  // that means that a cmd buffer we were relying on to signal this likely
  // never finished. This shouldn't happen unless there is a bug in the
  // encoder logic. We set it to zero anyway to prevent a validation error
  // from becoming a memory leak.
  FML_DCHECK(state.pending_buffers == 0u);
  state.pending_buffers = 0;
  state.current_index = 0;
}

MarkFrameStart()

void impeller::GPUTracerVK::MarkFrameStart

(

)

Signal the start of a frame workload.

   Any cmd buffers that are created after this call and before
   [MarkFrameEnd] will be attributed to the current frame. 

Definition at line 75 of file gpu_tracer_vk.cc.

                                 {
  if (!enabled_) {
    return;
  }
  FML_DCHECK(!in_frame_);
  in_frame_ = true;
  raster_thread_id_ = std::this_thread::get_id();
}

Friends And Related Function Documentation

GPUProbe

friend class GPUProbe

friend

Definition at line 52 of file gpu_tracer_vk.h.

---

The documentation for this class was generated from the following files:

• impeller/renderer/backend/vulkan/gpu_tracer_vk.h
• impeller/renderer/backend/vulkan/gpu_tracer_vk.cc