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[Perf] (MG_Backend/DirectVulkan): zero-copy UBO bind - point descriptor at the app's persistent VkBuffer instead of a per-draw transient copy; fps 127->166

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This commit is contained in:
swung0x48
2026-07-12 10:11:49 -04:00
parent 375f2df694
commit acaa9f6dc7
2 changed files with 61 additions and 19 deletions
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MobileGL/MG_Backend/DirectVulkan/Renderer/UniformManager.cpp
+50 -18
View File
@@ -578,9 +578,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
Bool UniformManager::ResolveUniformBufferPayload(const MG_State::GLState::ProgramObject& program,
const ProgramFactory::VkProgramObject& programObj, Uint32 binding,
const void*& outData, VkDeviceSize& outSize) const {
outData = nullptr;
outSize = 0;
UboBindResult& out) const {
const void* outData = nullptr;
VkDeviceSize outSize = 0;
MOBILEGL_ASSERT(MG_State::pGLContext != nullptr, "ResolveUniformBufferPayload: GL context is null");
MOBILEGL_ASSERT(binding < programObj.bindingKinds.size(),
@@ -596,6 +596,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
outData = emptyGlobalUbo.data();
outSize = static_cast<VkDeviceSize>(emptyGlobalUbo.size());
}
// The global UBO is CPU uniform data, not an app buffer -> always UploadTransient.
out.payload = outData;
out.payloadSize = outSize;
return outData != nullptr && outSize > 0;
}
@@ -659,6 +662,26 @@ namespace MobileGL::MG_Backend::DirectVulkan {
Memcpy(paddedUbo.data(), outData, static_cast<SizeT>(available));
outData = paddedUbo.data();
}
out.payload = outData;
out.payloadSize = outSize;
// Zero-copy direct bind: for a persistent-mapped coherent app buffer whose full reflected
// block fits within the aligned bound range, point the descriptor straight at the app's
// resident VkBuffer (the same buffer the GLES backend binds) with the block range as the
// dynamic offset - no per-draw copy into a transient ring. Any gate failing keeps the
// UploadTransient payload above. AcquireResidentSlice does the persistent busy-tracking and
// (for the persistent case) hits a zero-work fast path returning the whole-buffer slice.
if (bufferObject->IsBackendPersistentMapped() && available >= blockSize &&
(rangeStart % m_minDynamicOffsetAlignment) == 0) {
BufferSlice slice{};
if (m_bufferManager->AcquireResidentSlice(BufferKind::Uniform, bufferObject, slice) &&
slice.IsValid() && slice.offset == 0 && slice.size >= rangeStart + blockSize) {
out.directBindable = true;
out.buffer = slice.buffer;
out.range = blockSize;
out.dynamicOffset = rangeStart;
}
}
return true;
}
@@ -850,31 +873,40 @@ namespace MobileGL::MG_Backend::DirectVulkan {
write.descriptorCount = 1;
if (kind == ProgramFactory::DescriptorBindingKind::UniformBufferDynamic) {
const void* payload = nullptr;
VkDeviceSize payloadSize = 0;
const Bool hasPayload = ResolveUniformBufferPayload(program, programObj, binding, payload, payloadSize);
MOBILEGL_ASSERT(hasPayload && payload != nullptr && payloadSize > 0,
UboBindResult ubo{};
const Bool hasPayload = ResolveUniformBufferPayload(program, programObj, binding, ubo);
MOBILEGL_ASSERT(hasPayload && ubo.payload != nullptr && ubo.payloadSize > 0,
"UniformDescriptorBinder::BindProgramUniformBuffers failed: missing UBO payload on binding %u",
binding);
BufferSlice slice{};
if (!m_bufferManager->UploadTransient(BufferKind::Uniform, frameIndex, payload, payloadSize,
m_minDynamicOffsetAlignment, slice)) {
MOBILEGL_ASSERT(false, "UniformDescriptorBinder::BindProgramUniformBuffers failed: UBO upload failed on binding %u",
binding);
return false;
}
VkDescriptorBufferInfo bufferInfo{};
bufferInfo.buffer = slice.buffer;
// Keep offset 0 (sub-range selected via the dynamic offset) so the hashed bufferInfo
// is stable across draws and the descriptor-set reuse cache keeps hitting.
bufferInfo.offset = 0;
bufferInfo.range = payloadSize;
Uint32 dynOffset;
if (ubo.directBindable) {
// Zero-copy: bind the app's resident VkBuffer directly, no per-draw memcpy.
bufferInfo.buffer = ubo.buffer;
bufferInfo.range = ubo.range;
dynOffset = static_cast<Uint32>(ubo.dynamicOffset);
} else {
BufferSlice slice{};
if (!m_bufferManager->UploadTransient(BufferKind::Uniform, frameIndex, ubo.payload,
ubo.payloadSize, m_minDynamicOffsetAlignment, slice)) {
MOBILEGL_ASSERT(false, "UniformDescriptorBinder::BindProgramUniformBuffers failed: UBO upload failed on binding %u",
binding);
return false;
}
bufferInfo.buffer = slice.buffer;
bufferInfo.range = ubo.payloadSize;
dynOffset = static_cast<Uint32>(slice.offset);
}
bufferInfos.push_back(bufferInfo);
write.descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC;
write.pBufferInfo = &bufferInfos.back();
writes.push_back(write);
dynamicOffsets.push_back(static_cast<Uint32>(slice.offset));
dynamicOffsets.push_back(dynOffset);
} else if (kind == ProgramFactory::DescriptorBindingKind::UniformTexelBuffer) {
VkBufferView bufferView = VK_NULL_HANDLE;
if (!ResolveTexelBufferDescriptor(program, programObj, binding, frameIndex, bufferView) ||
MobileGL/MG_Backend/DirectVulkan/Renderer/UniformManager.h
+11 -1
View File
@@ -89,9 +89,19 @@ namespace MobileGL::MG_Backend::DirectVulkan {
const MG_State::GLState::ProgramObject& program,
const ProgramFactory::VkProgramObject& programObj, Uint32 binding,
VkDescriptorImageInfo& outImageInfo) const;
// Result of resolving a UBO binding: either a zero-copy direct bind to the app's resident
// VkBuffer (the GLES backend's approach - no per-draw copy) or the CPU payload to upload.
struct UboBindResult {
Bool directBindable = false;
VkBuffer buffer = VK_NULL_HANDLE;
VkDeviceSize range = 0; // reflected block size; constant across draws (hashed)
VkDeviceSize dynamicOffset = 0; // block range start; moves per draw (NOT hashed)
const void* payload = nullptr; // fallback UploadTransient path
VkDeviceSize payloadSize = 0;
};
Bool ResolveUniformBufferPayload(const MG_State::GLState::ProgramObject& program,
const ProgramFactory::VkProgramObject& programObj, Uint32 binding,
const void*& outData, VkDeviceSize& outSize) const;
UboBindResult& out) const;
Bool CreateDescriptorPool(Uint32 maxSets, VkDescriptorPool& outPool) const;
Bool GrowFrameDescriptorPool(FrameResources& frame, Uint32 frameIndex);
VkResult AllocateDescriptorSetsFromActivePool(