Performance chasing

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.cpp

@@ -8,7 +8,9 @@
 #include <cstring>
 
 #include <chrono>
+#include <cstdlib>
 #include <gl/gl.h>
+#include <string>
 
 OpenGLRenderPipeline::OpenGLRenderPipeline(
 	OpenGLRenderer& renderer,
@@ -22,7 +24,8 @@ OpenGLRenderPipeline::OpenGLRenderPipeline(
 	mHealthTelemetry(healthTelemetry),
 	mRenderEffect(renderEffect),
 	mOutputReady(outputReady),
-	mPaint(paint)
+	mPaint(paint),
+	mOutputReadbackMode(ReadOutputReadbackModeFromEnvironment())
 {
 }
 
@@ -53,9 +56,22 @@ bool OpenGLRenderPipeline::RenderFrame(const RenderPipelineFrameContext& context
 	mHealthTelemetry.TryRecordPerformanceStats(state.frameBudgetMilliseconds, renderMilliseconds);
 	mRuntimeSnapshotProvider.AdvanceFrame();
 
-	ReadOutputFrame(state, outputFrame);
-	if (mPaint)
-		mPaint();
+	OutputReadbackTiming readbackTiming = ReadOutputFrame(state, outputFrame);
+	mHealthTelemetry.TryRecordOutputRenderPipelineTiming(
+		renderMilliseconds,
+		readbackTiming.fenceWaitMilliseconds,
+		readbackTiming.mapMilliseconds,
+		readbackTiming.copyMilliseconds,
+		readbackTiming.cachedCopyMilliseconds,
+		readbackTiming.asyncQueueMilliseconds,
+		readbackTiming.asyncQueueBufferMilliseconds,
+		readbackTiming.asyncQueueSetupMilliseconds,
+		readbackTiming.asyncQueueReadPixelsMilliseconds,
+		readbackTiming.asyncQueueFenceMilliseconds,
+		readbackTiming.syncReadMilliseconds,
+		readbackTiming.asyncReadbackMissed,
+		readbackTiming.cachedFallbackUsed,
+		readbackTiming.syncFallbackUsed);
 
 	return true;
 }
@@ -151,8 +167,9 @@ void OpenGLRenderPipeline::FlushAsyncReadbackPipeline()
 	mAsyncReadbackReadIndex = 0;
 }
 
-void OpenGLRenderPipeline::QueueAsyncReadback(const VideoIOState& state)
+bool OpenGLRenderPipeline::QueueAsyncReadback(const VideoIOState& state, OutputReadbackTiming& timing)
 {
+	const auto queueStartTime = std::chrono::steady_clock::now();
 	const bool usePackedOutput = state.outputPixelFormat == VideoIOPixelFormat::V210 || state.outputPixelFormat == VideoIOPixelFormat::Yuva10;
 	const std::size_t requiredBytes = static_cast<std::size_t>(state.outputFrameRowBytes) * state.outputFrameSize.height;
 	const GLenum format = usePackedOutput ? GL_RGBA : GL_BGRA;
@@ -161,8 +178,16 @@ void OpenGLRenderPipeline::QueueAsyncReadback(const VideoIOState& state)
 	const GLsizei readWidth = static_cast<GLsizei>(usePackedOutput ? state.outputPackTextureWidth : state.outputFrameSize.width);
 	const GLsizei readHeight = static_cast<GLsizei>(state.outputFrameSize.height);
 
+	const auto finishTiming = [&timing, queueStartTime]() {
+		const auto queueEndTime = std::chrono::steady_clock::now();
+		timing.asyncQueueMilliseconds += std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(queueEndTime - queueStartTime).count();
+	};
+
 	if (requiredBytes == 0)
-		return;
+	{
+		finishTiming();
+		return false;
+	}
 
 	if (mAsyncReadbackBytes != requiredBytes
 		|| mAsyncReadbackFormat != format
@@ -173,30 +198,50 @@ void OpenGLRenderPipeline::QueueAsyncReadback(const VideoIOState& state)
 		mAsyncReadbackType = type;
 		mAsyncReadbackFramebuffer = framebuffer;
 		if (!EnsureAsyncReadbackBuffers(requiredBytes))
-			return;
+		{
+			finishTiming();
+			return false;
+		}
 	}
 
 	AsyncReadbackSlot& slot = mAsyncReadbackSlots[mAsyncReadbackWriteIndex];
-	if (slot.fence != nullptr)
+	if (slot.inFlight)
 	{
-		glDeleteSync(slot.fence);
-		slot.fence = nullptr;
+		finishTiming();
+		return false;
 	}
 
+	auto stageStartTime = std::chrono::steady_clock::now();
 	glPixelStorei(GL_PACK_ALIGNMENT, 4);
 	glPixelStorei(GL_PACK_ROW_LENGTH, 0);
 	glBindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
 	glBindBuffer(GL_PIXEL_PACK_BUFFER, slot.pixelPackBuffer);
+	auto stageEndTime = std::chrono::steady_clock::now();
+	timing.asyncQueueSetupMilliseconds += std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(stageEndTime - stageStartTime).count();
+
+	stageStartTime = std::chrono::steady_clock::now();
 	glBufferData(GL_PIXEL_PACK_BUFFER, static_cast<GLsizeiptr>(requiredBytes), nullptr, GL_STREAM_READ);
+	stageEndTime = std::chrono::steady_clock::now();
+	timing.asyncQueueBufferMilliseconds += std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(stageEndTime - stageStartTime).count();
+
+	stageStartTime = std::chrono::steady_clock::now();
 	glReadPixels(0, 0, readWidth, readHeight, format, type, nullptr);
+	stageEndTime = std::chrono::steady_clock::now();
+	timing.asyncQueueReadPixelsMilliseconds += std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(stageEndTime - stageStartTime).count();
+
+	stageStartTime = std::chrono::steady_clock::now();
 	slot.fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
+	stageEndTime = std::chrono::steady_clock::now();
+	timing.asyncQueueFenceMilliseconds += std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(stageEndTime - stageStartTime).count();
 	slot.inFlight = slot.fence != nullptr;
 	glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
 
 	mAsyncReadbackWriteIndex = (mAsyncReadbackWriteIndex + 1) % mAsyncReadbackSlots.size();
+	finishTiming();
+	return slot.inFlight;
 }
 
-bool OpenGLRenderPipeline::TryConsumeAsyncReadback(VideoIOOutputFrame& outputFrame, GLuint64 timeoutNanoseconds)
+bool OpenGLRenderPipeline::TryConsumeAsyncReadback(VideoIOOutputFrame& outputFrame, GLuint64 timeoutNanoseconds, OutputReadbackTiming& timing)
 {
 	if (mAsyncReadbackBytes == 0 || outputFrame.bytes == nullptr)
 		return false;
@@ -206,15 +251,24 @@ bool OpenGLRenderPipeline::TryConsumeAsyncReadback(VideoIOOutputFrame& outputFra
 		return false;
 
 	const GLenum waitFlags = timeoutNanoseconds > 0 ? GL_SYNC_FLUSH_COMMANDS_BIT : 0;
+	const auto waitStartTime = std::chrono::steady_clock::now();
 	const GLenum waitResult = glClientWaitSync(slot.fence, waitFlags, timeoutNanoseconds);
+	const auto waitEndTime = std::chrono::steady_clock::now();
+	timing.fenceWaitMilliseconds += std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(waitEndTime - waitStartTime).count();
 	if (waitResult != GL_ALREADY_SIGNALED && waitResult != GL_CONDITION_SATISFIED)
+	{
+		timing.asyncReadbackMissed = true;
 		return false;
+	}
 
 	glDeleteSync(slot.fence);
 	slot.fence = nullptr;
 
 	glBindBuffer(GL_PIXEL_PACK_BUFFER, slot.pixelPackBuffer);
+	const auto mapStartTime = std::chrono::steady_clock::now();
 	void* mappedBytes = glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
+	const auto mapEndTime = std::chrono::steady_clock::now();
+	timing.mapMilliseconds += std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(mapEndTime - mapStartTime).count();
 	if (mappedBytes == nullptr)
 	{
 		glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
@@ -223,7 +277,10 @@ bool OpenGLRenderPipeline::TryConsumeAsyncReadback(VideoIOOutputFrame& outputFra
 		return false;
 	}
 
+	const auto copyStartTime = std::chrono::steady_clock::now();
 	std::memcpy(outputFrame.bytes, mappedBytes, slot.sizeBytes);
+	const auto copyEndTime = std::chrono::steady_clock::now();
+	timing.copyMilliseconds += std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(copyEndTime - copyStartTime).count();
 	glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
 	glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
 
@@ -243,8 +300,26 @@ void OpenGLRenderPipeline::CacheOutputFrame(const VideoIOOutputFrame& outputFram
 	std::memcpy(mCachedOutputFrame.data(), outputFrame.bytes, byteCount);
 }
 
-void OpenGLRenderPipeline::ReadOutputFrameSynchronously(const VideoIOState& state, void* destinationBytes)
+bool OpenGLRenderPipeline::TryCopyCachedOutputFrame(VideoIOOutputFrame& outputFrame, OutputReadbackTiming& timing) const
 {
+	if (outputFrame.bytes == nullptr || outputFrame.height == 0 || outputFrame.rowBytes <= 0)
+		return false;
+
+	const std::size_t byteCount = static_cast<std::size_t>(outputFrame.rowBytes) * outputFrame.height;
+	if (mCachedOutputFrame.size() != byteCount)
+		return false;
+
+	const auto copyStartTime = std::chrono::steady_clock::now();
+	std::memcpy(outputFrame.bytes, mCachedOutputFrame.data(), byteCount);
+	const auto copyEndTime = std::chrono::steady_clock::now();
+	timing.cachedCopyMilliseconds += std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(copyEndTime - copyStartTime).count();
+	timing.cachedFallbackUsed = true;
+	return true;
+}
+
+void OpenGLRenderPipeline::ReadOutputFrameSynchronously(const VideoIOState& state, void* destinationBytes, OutputReadbackTiming& timing)
+{
+	const auto readStartTime = std::chrono::steady_clock::now();
 	const bool usePackedOutput = state.outputPixelFormat == VideoIOPixelFormat::V210 || state.outputPixelFormat == VideoIOPixelFormat::Yuva10;
 
 	glPixelStorei(GL_PACK_ALIGNMENT, 4);
@@ -259,24 +334,78 @@ void OpenGLRenderPipeline::ReadOutputFrameSynchronously(const VideoIOState& stat
 		glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.OutputFramebuffer());
 		glReadPixels(0, 0, state.outputFrameSize.width, state.outputFrameSize.height, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, destinationBytes);
 	}
+	const auto readEndTime = std::chrono::steady_clock::now();
+	timing.syncReadMilliseconds += std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(readEndTime - readStartTime).count();
+	timing.syncFallbackUsed = true;
 }
 
-void OpenGLRenderPipeline::ReadOutputFrame(const VideoIOState& state, VideoIOOutputFrame& outputFrame)
+OpenGLRenderPipeline::OutputReadbackTiming OpenGLRenderPipeline::ReadOutputFrame(const VideoIOState& state, VideoIOOutputFrame& outputFrame)
 {
-	if (TryConsumeAsyncReadback(outputFrame, 500000))
+	OutputReadbackTiming timing;
+
+	if (mOutputReadbackMode == OutputReadbackMode::Synchronous)
 	{
-		QueueAsyncReadback(state);
-		return;
+		if (outputFrame.bytes != nullptr)
+		{
+			ReadOutputFrameSynchronously(state, outputFrame.bytes, timing);
+			CacheOutputFrame(outputFrame);
+		}
+		return timing;
 	}
 
-	// If async readback misses the playout deadline, prefer a fresh synchronous
-	// frame over reusing stale cached output, then restart the async pipeline.
-	if (outputFrame.bytes != nullptr)
+	if (mOutputReadbackMode == OutputReadbackMode::CachedOnly)
 	{
-		ReadOutputFrameSynchronously(state, outputFrame.bytes);
+		if (TryCopyCachedOutputFrame(outputFrame, timing))
+			return timing;
+
+		if (outputFrame.bytes != nullptr)
+		{
+			ReadOutputFrameSynchronously(state, outputFrame.bytes, timing);
+			CacheOutputFrame(outputFrame);
+		}
+		return timing;
+	}
+
+	if (TryConsumeAsyncReadback(outputFrame, 500000, timing))
+	{
+		(void)QueueAsyncReadback(state, timing);
+		return timing;
+	}
+
+	if (TryCopyCachedOutputFrame(outputFrame, timing))
+	{
+		(void)QueueAsyncReadback(state, timing);
+		return timing;
+	}
+
+	// Bootstrap only: until the first async readback has produced cached output,
+	// use one synchronous readback so DeckLink has a valid frame to schedule.
+	if (outputFrame.bytes != nullptr && mCachedOutputFrame.empty())
+	{
+		ReadOutputFrameSynchronously(state, outputFrame.bytes, timing);
 		CacheOutputFrame(outputFrame);
 	}
 
 	FlushAsyncReadbackPipeline();
-	QueueAsyncReadback(state);
+	(void)QueueAsyncReadback(state, timing);
+	return timing;
+}
+
+OpenGLRenderPipeline::OutputReadbackMode OpenGLRenderPipeline::ReadOutputReadbackModeFromEnvironment()
+{
+	char* mode = nullptr;
+	std::size_t modeSize = 0;
+	if (_dupenv_s(&mode, &modeSize, "VST_OUTPUT_READBACK_MODE") != 0 || mode == nullptr)
+		return OutputReadbackMode::AsyncPbo;
+
+	const std::string modeValue(mode);
+	std::free(mode);
+	if (modeValue == "async_pbo")
+		return OutputReadbackMode::AsyncPbo;
+	if (modeValue == "sync")
+		return OutputReadbackMode::Synchronous;
+	if (modeValue == "cached_only")
+		return OutputReadbackMode::CachedOnly;
+
+	return OutputReadbackMode::AsyncPbo;
 }