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Vulkan: Support subgroup reduction operations via GL_KHR_shader_subgroup

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stenzek committed Mar 22, 2019
1 parent 86da282 commit 6561850f2bbb8e6faa98e23bdf8293c002fbd405
@@ -17,6 +17,7 @@
#include "ShaderLang.h"
#include "disassemble.h"

#include "Common/CommonFuncs.h"
#include "Common/FileUtil.h"
#include "Common/Logging/Log.h"
#include "Common/MsgHandler.h"
@@ -99,6 +100,18 @@ static const char COMPUTE_SHADER_HEADER[] = R"(
#define frac fract
#define lerp mix
)";
static const char SUBGROUP_HELPER_HEADER[] = R"(
#extension GL_KHR_shader_subgroup_basic : enable
#extension GL_KHR_shader_subgroup_arithmetic : enable
#extension GL_KHR_shader_subgroup_ballot : enable
#define SUPPORTS_SUBGROUP_REDUCTION 1
#define CAN_USE_SUBGROUP_REDUCTION true
#define IS_HELPER_INVOCATION gl_HelperInvocation
#define IS_FIRST_ACTIVE_INVOCATION (gl_SubgroupInvocationID == subgroupBallotFindLSB(subgroupBallot(true)))
#define SUBGROUP_MIN(value) value = subgroupMin(value)
#define SUBGROUP_MAX(value) value = subgroupMax(value)
)";

bool CompileShaderToSPV(SPIRVCodeVector* out_code, EShLanguage stage, const char* stage_filename,
const char* source_code, size_t source_code_length, const char* header,
@@ -120,13 +133,20 @@ bool CompileShaderToSPV(SPIRVCodeVector* out_code, EShLanguage stage, const char
int pass_source_code_length = static_cast<int>(source_code_length);
if (header_length > 0)
{
full_source_code.reserve(header_length + source_code_length);
constexpr size_t subgroup_helper_header_length = ArraySize(SUBGROUP_HELPER_HEADER) - 1;
full_source_code.reserve(header_length + subgroup_helper_header_length + source_code_length);
full_source_code.append(header, header_length);
if (g_vulkan_context->SupportsShaderSubgroupOperations())
full_source_code.append(SUBGROUP_HELPER_HEADER, subgroup_helper_header_length);
full_source_code.append(source_code, source_code_length);
pass_source_code = full_source_code.c_str();
pass_source_code_length = static_cast<int>(full_source_code.length());
}

// Sub-group operations require Vulkan 1.1 and SPIR-V 1.3.
if (g_vulkan_context->SupportsShaderSubgroupOperations())
shader->setEnvTarget(glslang::EShTargetSpv, glslang::EShTargetSpv_1_3);

shader->setStringsWithLengths(&pass_source_code, &pass_source_code_length, 1);

auto DumpBadShader = [&](const char* msg) {
@@ -384,6 +384,7 @@ std::unique_ptr<VulkanContext> VulkanContext::Create(VkInstance instance, VkPhys

// Initialize DriverDetails so that we can check for bugs to disable features if needed.
context->InitDriverDetails();
context->PopulateShaderSubgroupSupport();

// Enable debug reports if the "Host GPU" log category is enabled.
if (enable_debug_reports)
@@ -864,4 +865,31 @@ void VulkanContext::InitDriverDetails()
static_cast<double>(m_device_properties.driverVersion),
DriverDetails::Family::UNKNOWN);
}

void VulkanContext::PopulateShaderSubgroupSupport()
{
// If this function isn't available, we don't support Vulkan 1.1.
if (!vkGetPhysicalDeviceProperties2)
return;

VkPhysicalDeviceProperties2 device_properties_2 = {};
device_properties_2.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2;

VkPhysicalDeviceSubgroupProperties subgroup_properties = {};
subgroup_properties.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_PROPERTIES;
device_properties_2.pNext = &subgroup_properties;

vkGetPhysicalDeviceProperties2(m_physical_device, &device_properties_2);

m_shader_subgroup_size = subgroup_properties.subgroupSize;

// We require basic ops (for gl_SubgroupInvocationID), ballot (for subgroupBallot,
// subgroupBallotFindLSB), and arithmetic (for subgroupMin/subgroupMax).
constexpr VkSubgroupFeatureFlags required_operations = VK_SUBGROUP_FEATURE_BASIC_BIT |
VK_SUBGROUP_FEATURE_ARITHMETIC_BIT |
VK_SUBGROUP_FEATURE_BALLOT_BIT;
m_supports_shader_subgroup_operations =
(subgroup_properties.supportedOperations & required_operations) == required_operations &&
subgroup_properties.supportedStages & VK_SHADER_STAGE_FRAGMENT_BIT;
}
} // namespace Vulkan
@@ -80,6 +80,8 @@ class VulkanContext
{
return m_device_features.occlusionQueryPrecise == VK_TRUE;
}
u32 GetShaderSubgroupSize() const { return m_shader_subgroup_size; }
bool SupportsShaderSubgroupOperations() const { return m_supports_shader_subgroup_operations; }

// Helpers for getting constants
VkDeviceSize GetUniformBufferAlignment() const
@@ -112,6 +114,7 @@ class VulkanContext
bool SelectDeviceFeatures();
bool CreateDevice(VkSurfaceKHR surface, bool enable_validation_layer);
void InitDriverDetails();
void PopulateShaderSubgroupSupport();

VkInstance m_instance = VK_NULL_HANDLE;
VkPhysicalDevice m_physical_device = VK_NULL_HANDLE;
@@ -128,6 +131,9 @@ class VulkanContext
VkPhysicalDeviceFeatures m_device_features = {};
VkPhysicalDeviceProperties m_device_properties = {};
VkPhysicalDeviceMemoryProperties m_device_memory_properties = {};

u32 m_shader_subgroup_size = 1;
bool m_supports_shader_subgroup_operations = false;
};

extern std::unique_ptr<VulkanContext> g_vulkan_context;
@@ -59,6 +59,7 @@ VULKAN_INSTANCE_ENTRY_POINT(vkCreateMacOSSurfaceMVK, false)
VULKAN_INSTANCE_ENTRY_POINT(vkCreateDebugReportCallbackEXT, false)
VULKAN_INSTANCE_ENTRY_POINT(vkDestroyDebugReportCallbackEXT, false)
VULKAN_INSTANCE_ENTRY_POINT(vkDebugReportMessageEXT, false)
VULKAN_INSTANCE_ENTRY_POINT(vkGetPhysicalDeviceProperties2, false)

#endif // VULKAN_INSTANCE_ENTRY_POINT

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