graphics: count occlusion queries on the host GPU behind --occlusion-queries

src/graphics/host_gpu/graphicContext.h

@@ -36,6 +36,8 @@ struct GraphicContext {
 	bool                               provoking_vertex_last_enabled         = false;
 	bool                               maintenance8_enabled                  = false;
 	bool                               conditional_rendering_enabled         = false;
+	bool                               occlusion_queries_enabled             = false;
+	bool                               occlusion_query_precise_enabled       = false;
 	bool                               supports_block_texel_view              = false;
 	bool                                      mesh_shader_enabled                   = false;
 	vk::PhysicalDeviceMeshShaderPropertiesEXT mesh_shader_properties                = {};

src/graphics/host_gpu/renderer/occlusionQueries.cpp

@@ -0,0 +1,82 @@
+#include "graphics/host_gpu/renderer/occlusionQueries.h"
+
+#include "graphics/host_gpu/graphicContext.h"
+#include "graphics/host_gpu/renderer/commandScheduler.h"
+
+#include <algorithm>
+
+namespace Libs::Graphics {
+
+// Queries no dump has read yet; past them a draw counts one sample.
+constexpr uint32_t QUERY_COUNT = 16384;
+
+OcclusionQueries::OcclusionQueries(GraphicContext& graphics, CommandScheduler& scheduler)
+    : m_scheduler(scheduler) {
+	if (!graphics.occlusion_queries_enabled) {
+		return;
+	}
+	m_device = graphics.device;
+	const vk::QueryPoolCreateInfo info {.queryType  = vk::QueryType::eOcclusion,
+	                                    .queryCount = QUERY_COUNT};
+	RequireVulkanSuccess(m_device.createQueryPool(&info, nullptr, &m_pool), "vkCreateQueryPool");
+	m_device.resetQueryPool(m_pool, 0, QUERY_COUNT);
+	m_results.resize(QUERY_COUNT);
+	if (graphics.occlusion_query_precise_enabled) {
+		m_control = vk::QueryControlFlagBits::ePrecise;
+	}
+}
+
+OcclusionQueries::~OcclusionQueries() {
+	if (m_pool) {
+		m_device.destroyQueryPool(m_pool, nullptr);
+	}
+}
+
+int32_t OcclusionQueries::BeginQuery(vk::CommandBuffer command) {
+	if (m_begun - m_read == QUERY_COUNT) {
+		m_uncounted++;
+		return -1;
+	}
+	const auto query = static_cast<uint32_t>(m_begun++ % QUERY_COUNT);
+	command.beginQuery(m_pool, query, m_control);
+	return static_cast<int32_t>(query);
+}
+
+void OcclusionQueries::Dump(uint64_t address) {
+	// Begins dump to the results, ends 8 bytes into them.
+	if ((address & 8u) == 0) {
+		m_open++;
+	} else if (m_open != 0) {
+		m_open--;
+	}
+	m_dumps.push_back({address, m_scheduler.CurrentTick(), m_begun, m_uncounted});
+}
+
+void OcclusionQueries::PublishDumps() {
+	if (const auto last = m_dumps.back().queries; last != m_read) {
+		m_scheduler.Wait(m_dumps.back().tick);
+		// The unread queries wrap around the pool at most once.
+		for (uint64_t read = m_read; read < last;) {
+			const auto first = static_cast<uint32_t>(read % QUERY_COUNT);
+			const auto count =
+			    static_cast<uint32_t>(std::min<uint64_t>(last - read, QUERY_COUNT - first));
+			RequireVulkanSuccess(
+			    m_device.getQueryPoolResults(m_pool, first, count, count * sizeof(uint64_t),
+				                             m_results.data() + first, sizeof(uint64_t),
+				                             vk::QueryResultFlagBits::e64),
+			    "vkGetQueryPoolResults");
+			m_device.resetQueryPool(m_pool, first, count);
+			read += count;
+		}
+	}
+	for (const auto& dump: m_dumps) {
+		for (; m_read < dump.queries; m_read++) {
+			m_samples += m_results[m_read % QUERY_COUNT];
+		}
+		WriteZPassCounters(reinterpret_cast<volatile uint64_t*>(dump.address),
+		                   m_samples + dump.uncounted, (dump.address & 8u) == 0);
+	}
+	m_dumps.clear();
+}
+
+} // namespace Libs::Graphics

src/graphics/host_gpu/renderer/occlusionQueries.h

@@ -0,0 +1,85 @@
+#ifndef EMULATOR_SRC_GRAPHICS_HOST_GPU_RENDERER_OCCLUSIONQUERIES_H_
+#define EMULATOR_SRC_GRAPHICS_HOST_GPU_RENDERER_OCCLUSIONQUERIES_H_
+
+#include "common/common.h"
+#include "graphics/host_gpu/vulkanCommon.h"
+
+#include <cstdint>
+#include <vector>
+
+namespace Libs::Graphics {
+
+class CommandScheduler;
+struct GraphicContext;
+
+// The guest's query results (16-byte aligned): a begin/end pair of running z-pass counters per DB,
+// 16 bytes apart; bit 63 marks a written counter. A query's samples are the sum of end - begin.
+constexpr uint32_t OCCLUSION_QUERY_DBS   = 16;
+constexpr uint64_t OCCLUSION_QUERY_READY = 1ull << 63u;
+
+// A dump of the running count, all of it in DB 0. A begin also clears its end counters.
+inline void WriteZPassCounters(volatile uint64_t* results, uint64_t samples, bool begin) {
+	for (uint32_t db = 0; db < OCCLUSION_QUERY_DBS; db++) {
+		results[db * 2] = OCCLUSION_QUERY_READY | (db == 0 ? samples : 0);
+		if (begin) {
+			results[db * 2 + 1] = 0;
+		}
+	}
+}
+
+// The guest's z-pass counters from host occlusion queries: a draw counts its samples while a guest
+// query is open, and the dumps' counters are written before the guest can see the GPU ran them.
+class OcclusionQueries {
+public:
+	OcclusionQueries(GraphicContext& graphics, CommandScheduler& scheduler);
+	~OcclusionQueries();
+	KYTY_CLASS_NO_COPY(OcclusionQueries);
+
+	[[nodiscard]] bool Enabled() const { return m_pool != nullptr; }
+
+	// In the draw's rendering: the query that counts its samples, or -1.
+	[[nodiscard]] int32_t Begin(vk::CommandBuffer command) {
+		return m_open == 0 ? -1 : BeginQuery(command);
+	}
+	void End(vk::CommandBuffer command, int32_t query) const {
+		if (query >= 0) {
+			command.endQuery(m_pool, static_cast<uint32_t>(query));
+		}
+	}
+
+	// A PIXEL_PIPE_STAT_DUMP to address, after the draws recorded so far.
+	void Dump(uint64_t address);
+	// Waits for the GPU to run the dumps and writes their counters.
+	void Publish() {
+		if (!m_dumps.empty()) {
+			PublishDumps();
+		}
+	}
+
+private:
+	struct PendingDump {
+		uint64_t address;
+		uint64_t tick;
+		uint64_t queries;
+		uint64_t uncounted;
+	};
+
+	int32_t BeginQuery(vk::CommandBuffer command);
+	void    PublishDumps();
+
+	CommandScheduler&        m_scheduler;
+	vk::Device               m_device;
+	vk::QueryPool            m_pool;
+	vk::QueryControlFlags    m_control;
+	std::vector<PendingDump> m_dumps;
+	std::vector<uint64_t>    m_results;
+	uint32_t                 m_open      = 0;
+	uint64_t                 m_begun     = 0;
+	uint64_t                 m_read      = 0;
+	uint64_t                 m_samples   = 0;
+	uint64_t                 m_uncounted = 0;
+};
+
+} // namespace Libs::Graphics
+
+#endif // EMULATOR_SRC_GRAPHICS_HOST_GPU_RENDERER_OCCLUSIONQUERIES_H_

src/graphics/host_gpu/renderer/renderContext.cpp

@@ -16,7 +16,7 @@ RenderContext::RenderContext(GraphicContext& graphics)
       m_pipeline_cache(graphics, &m_image_heap), m_sampler_cache(graphics),
       m_buffer_cache(graphics, m_command_scheduler, m_page_manager, m_texture_cache),
       m_texture_cache(graphics, m_command_scheduler, m_page_manager, m_buffer_cache),
-      m_image_heap(*this, m_page_manager) {
+      m_image_heap(*this, m_page_manager), m_occlusion_queries(graphics, m_command_scheduler) {
 	EXIT_NOT_IMPLEMENTED(!Common::Thread::IsMainThread());
 }
 

src/graphics/host_gpu/renderer/renderContext.h

@@ -11,6 +11,7 @@
 #include "graphics/host_gpu/renderer/cache/samplerCache.h"
 #include "graphics/host_gpu/renderer/cache/textureCache.h"
 #include "graphics/host_gpu/renderer/commandScheduler.h"
+#include "graphics/host_gpu/renderer/occlusionQueries.h"
 #include "graphics/host_gpu/renderer/pipeline/descriptorHeap.h"
 #include "graphics/host_gpu/renderer/pipeline/imageHeap.h"
 #include "graphics/host_gpu/renderer/pipeline/pipelineCache.h"
@@ -49,6 +50,7 @@ public:
 	BufferCache&        GetBufferCache() { return m_buffer_cache; }
 	TextureCache&       GetTextureCache() { return m_texture_cache; }
 	RenderExecutor&     GetRenderExecutor() { return m_render_executor; }
+	OcclusionQueries&   GetOcclusionQueries() { return m_occlusion_queries; }
 
 	[[nodiscard]] bool HandleFault(PageFaultAccess access, uint64_t fault_vaddr) noexcept;
 	[[nodiscard]] bool InvalidateMemory(uint64_t vaddr, uint64_t size);
@@ -79,6 +81,7 @@ private:
 	BufferCache               m_buffer_cache;
 	TextureCache              m_texture_cache;
 	ImageHeap                 m_image_heap;
+	OcclusionQueries          m_occlusion_queries;
 	mutable std::shared_mutex m_mapped_ranges_mutex;
 	RangeSet                  m_mapped_ranges;
 	std::unique_ptr<GuestGpu> m_gpu;

src/graphics/host_gpu/renderer/renderDraw.cpp

@@ -1284,6 +1284,8 @@ void RenderExecutor::ExecutePreparedDraw(uint64_t submit_id, CommandBuffer& buff
 	if (!draw.IsIndexed()) {
 		SetDrawDebugPhase(buffer, submit_id, draw, 0x500u);
 	}
+	auto&         occlusion_queries = m_context.GetOcclusionQueries();
+	const int32_t occlusion_query   = occlusion_queries.Begin(vk_buffer);
 	if (mesh_active) {
 		vk_buffer.drawMeshTasksEXT(mesh_groups, draw.instance_count, 1);
 	} else if (args_buffer.first == nullptr) {
@@ -1295,6 +1297,7 @@ void RenderExecutor::ExecutePreparedDraw(uint64_t submit_id, CommandBuffer& buff
 		vk_buffer.drawIndirect(args_buffer.first->Handle(), args_buffer.second,
 		                       emit.indirect.count, emit.indirect.stride);
 	}
+	occlusion_queries.End(vk_buffer, occlusion_query);
 	Common::DebugCounters::Add(Common::DebugCounters::Counter::Draws);
 	Common::DebugCounters::Add(Common::DebugCounters::Counter::DrawInstances, draw.instance_count);