系列文章目录

MNN createFromBuffer（一）
MNN createRuntime（二）
MNN createSession 之 Schedule（三）
MNN createSession 之创建流水线后端（四）
MNN Session::resize 之流水线编码（五）
MNN Session 创建执行器（六）

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1、createRuntime

    根据 ScheduleConfig 创建运行时 Runtime 。RuntimeInfo 的定义见 2.1，其 first 用来存放根据 configs 创建的 Runtime（如 VulkanRuntime，CUDARuntime），它的 second 存放的是默认 Runtime，一般为 CPURuntime 。

RuntimeInfo Interpreter::createRuntime(const std::vector<ScheduleConfig>& configs) {RuntimeInfo res;// 根据 configs 创建的 Runtime 存放在这里auto& mRuntimes = res.first;for (auto& config : configs) {Backend::Info compute;compute.type      = Schedule::getApprociateType(config);compute.numThread = config.numThread;if(config.type == MNN_FORWARD_AUTO) {if(compute.type == MNN_FORWARD_OPENCL || compute.type == MNN_FORWARD_METAL) {// AUTO set default gpu-mode MNN_GPU_TUNING_FASTcompute.numThread = 16;}}compute.user      = config.backendConfig;if (mRuntimes.find(compute.type) == mRuntimes.end()) {auto newBn = RuntimeFactory::create(compute);if (nullptr == newBn) {MNN_ERROR("Can't create Runtime: %s\n", EnumNameForwardType((ForwardType)compute.type));continue;}mRuntimes[compute.type].reset(newBn);}}_getDefaultBackend(res);return res;
}

1.1 RuntimeInfo

typedef std::pair< std::map<MNNForwardType, std::shared_ptr<Runtime>>, \std::shared_ptr<Runtime>> RuntimeInfo;

1.2 Schedule::getApprociateType

// source/core/Schedule.cpp
MNNForwardType Schedule::getApprociateType(const ScheduleConfig& config) {MNNForwardType type = config.type;// FIXME: Support Auto determine// MNN_FORWARD_AUTO 的处理逻辑if (MNN_FORWARD_AUTO == config.type) {//Define Auto choose prioritystd::vector<MNNForwardType> priorityList;priorityList.push_back(MNN_FORWARD_USER_0); //HIAIpriorityList.push_back(MNN_FORWARD_NN);     //CoreMLpriorityList.push_back(MNN_FORWARD_USER_1); //TensoRTpriorityList.push_back(MNN_FORWARD_CUDA);   //CUDApriorityList.push_back(MNN_FORWARD_OPENCL); //OpenCLpriorityList.push_back(MNN_FORWARD_METAL);  //METALpriorityList.push_back(MNN_FORWARD_VULKAN); //VulkanpriorityList.push_back(MNN_FORWARD_CPU);    //CPUfor (auto bn : priorityList) {if (MNNGetExtraRuntimeCreator(bn) != nullptr) {type = (MNNForwardType)bn;break;}}}auto creator = MNNGetExtraRuntimeCreator(type);if (nullptr == creator) {MNN_PRINT("Can't Find type=%d backend, use %d instead\n", type, config.backupType);type = config.backupType;} else {// TODO : Not Limited to openclif(type == MNN_FORWARD_OPENCL && config.backendConfig != nullptr) {if(config.backendConfig->power == BackendConfig::Power_Low) {Backend::Info info;info.type = type;std::shared_ptr<Runtime> bn(creator->onCreate(info));bool isSupportLowPower = bn->onGetRuntimeStatus(RuntimeStatus::STATUS_SUPPORT_POWER_LOW);if(!isSupportLowPower) {MNN_PRINT("type=%d backend don't Support Low Power, use %d instead\n", type, config.backupType);type = config.backupType;}}}}return type;
}

1.2.1 MNNGetExtraRuntimeCreator

// source/core/Backend.cpp
const RuntimeCreator* MNNGetExtraRuntimeCreator(MNNForwardType type) {registerBackend();// 获取运行时创建器// （std::map<MNNForwardType, std::pair<const RuntimeCreator*, bool>>类型）auto& gExtraCreator = GetExtraCreator();// 根据推理类型查找运行时创建器auto iter           = gExtraCreator.find(type);if (iter == gExtraCreator.end()) {return nullptr;}// iter->second 的类型为 std::pair<const RuntimeCreator* creator, bool needCheck>if (!iter->second.second) {return iter->second.first;}Backend::Info info;info.type = type;std::shared_ptr<Runtime> bn(iter->second.first->onCreate(info));if (nullptr != bn.get()) {return iter->second.first;}return nullptr;
}

1.2.1.1 registerBackend

static std::once_flag s_flag;
void registerBackend() {std::call_once(s_flag, [&]() {
#ifdef MNN_INTERNAL_ENABLEDLogInit();
#endif// 注册 CPU 的运行时创建器和一些核心函数registerCPURuntimeCreator();
#ifndef MNN_BUILD_MINISizeComputerSuite::init();// 图像着色器 ？GeometryComputer::init();
#endif
#if MNN_COREML_ENABLEDregisterCoreMLRuntimeCreator();
#endif
#ifdef MNN_NNAPI_ENABLEDregisterNNAPIRuntimeCreator();
#endif
#if MNN_OPENCL_ENABLEDOpenCL::registerOpenCLRuntimeCreator();
#endif
#if MNN_METAL_ENABLEDregisterMetalRuntimeCreator();
#endif});
}

1.2.1.2 GetExtraCreator

static std::map<MNNForwardType, std::pair<const RuntimeCreator*, bool>>& GetExtraCreator() {static std::once_flag gInitFlag;static std::map<MNNForwardType, std::pair<const RuntimeCreator*, bool>>* gExtraCreator;std::call_once(gInitFlag,[&]() { gExtraCreator = new std::map<MNNForwardType, std::pair<const RuntimeCreator*, bool>>; });return *gExtraCreator;
}

    获取 RuntimeCreator ，然后根据类型创建对应的 Runtime。gExtraCreator 是一个 map 类型，其是通过函数 MNNInsertExtraRuntimeCreator 进行注册的。

// source/core/Backend.cpp
bool MNNInsertExtraRuntimeCreator(MNNForwardType type, const RuntimeCreator* creator, bool needCheck) {auto& gExtraCreator = GetExtraCreator();if (gExtraCreator.find(type) != gExtraCreator.end()) {MNN_ASSERT(false && "duplicate type");return false;}gExtraCreator.insert(std::make_pair(type, std::make_pair(creator, needCheck)));return true;
}

• VULKAN 注册

// source/backend/vulkan/runtime/VulkanRuntime.cpp
static bool gResistor = []() {MNNInsertExtraRuntimeCreator(MNN_FORWARD_VULKAN, new VulkanRuntimeCreator, false);return false;
}();

• CUDA 注册

// source/backend/cuda/Register.cpp
static const auto __cuda_global_initializer = []() {MNNInsertExtraRuntimeCreator(MNN_FORWARD_CUDA, new CUDARuntimeCreator, false);return true;
}();

• OPENGL 注册

// source/backend/opengl/GLBackend.cpp
bool placeholder = []() {static std::once_flag createOnce;std::call_once(createOnce, []() {MNNInsertExtraRuntimeCreator(MNN_FORWARD_OPENGL, new GLRuntimeCreator, false);});return true;
}();

• Metal 注册，在 registerBackend 中主动调用

// source/backend/metal/MetalBackend.mm
void registerMetalRuntimeCreator() {// according to// https://developer.apple.com/library/archive/documentation/DeviceInformation/Reference/iOSDeviceCompatibility/HardwareGPUInformation/HardwareGPUInformation.html// not all device with iOS 8+ supports metal.id<MTLDevice> device = MTLCreateSystemDefaultDevice();if (nil != device) {registerMetalOps();
#ifdef MNN_SUPPORT_RENDERregisterMetalRenderOps();
#endifMNNInsertExtraRuntimeCreator(MNN_FORWARD_METAL, new MetalRuntimeCreator(device), false);} else {MNN_ERROR("Init Metal Error\n");}
}

1.3 RuntimeFactory::create

Runtime* RuntimeFactory::create(const Backend::Info& info) {auto creator = MNNGetExtraRuntimeCreator(info.type);if (nullptr == creator) {MNN_PRINT("Create Runtime Failed because no creator for %d\n", info.type);return nullptr;}// 调用具体 RuntimeCreator，如 VulkanRuntimeCreator，MetalRuntimeCreator，GLRuntimeCreatorauto runtime = creator->onCreate(info);if (nullptr == runtime) {MNN_PRINT("Create Runtime failed, the creator return nullptr, type = %d\n", info.type);}return runtime;
}

1.3.1 VulkanRuntimeCreator

    若 RuntimeFactory::create 中 info.type 为 MNN_FORWARD_VULKAN，则 creator->onCreate(info) 实际调用的是 VulkanRuntimeCreator::onCreate 函数。

// source/backend/vulkan/runtime/VulkanRuntime.cpp
class VulkanRuntimeCreator : public RuntimeCreator {
public:virtual Runtime* onCreate(const Backend::Info& info) const {// 初始化 Vulkan 库，获取相应的 API 函数if (InitVulkan()) {if (_testVulkan()) {// 创建 Vulkan 运行时return new VulkanRuntime(info);}}return nullptr;}virtual bool onValid(Backend::Info& info) const {return true;}
};static bool gResistor = []() {MNNInsertExtraRuntimeCreator(MNN_FORWARD_VULKAN, new VulkanRuntimeCreator, false);return false;
}();
}

1.3.2 VulkanRuntimeCreator

    若 RuntimeFactory::create 中 info.type 为 MNN_FORWARD_CPU，则 creator->onCreate(info) 实际调用的是 CPURuntimeCreator ::onCreate 函数。

class CPURuntimeCreator : public RuntimeCreator {
public:virtual Runtime* onCreate(const Backend::Info& info) const override {return new CPURuntime(info);}
};#ifdef MNN_SUPPORT_BF16
extern void registerBF16Backend();
#endif
#ifdef ENABLE_ARMV82
extern void registerArm82RuntimeCreator();
#endif
void registerCPURuntimeCreator() {CPUBackend::initCreatorMap();registerCPUOps();
#ifdef MNN_SUPPORT_BF16registerBF16Backend();
#endif
#ifdef MNN_USE_ARMV82registerArm82RuntimeCreator();
#endif// TODO: Merge _initCoreFunction MNNFunctionInit and cpuinfo_arm_initMNNCoreFunctionInit();MNNInsertExtraRuntimeCreator(MNN_FORWARD_CPU, new CPURuntimeCreator);
};

1.4 ScheduleConfig

// project/android/demo/app/includes/MNN/Interpreter.hpp
/** session schedule config */
struct ScheduleConfig {/** which tensor should be kept */std::vector<std::string> saveTensors;/** forward type */MNNForwardType type = MNN_FORWARD_CPU;/** number of threads in parallel */int numThread = 4;/** subpath to run */struct Path {std::vector<std::string> inputs;std::vector<std::string> outputs;enum Mode {/*** Op Mode* - inputs means the source op, can NOT be empty.* - outputs means the sink op, can be empty.* The path will start from source op, then flow when encounter the sink op.* The sink op will not be compute in this path.*/Op = 0,/*** Tensor Mode (NOT supported yet)* - inputs means the inputs tensors, can NOT be empty.* - outputs means the outputs tensors, can NOT be empty.* It will find the pipeline that compute outputs from inputs.*/Tensor = 1};/** running mode */Mode mode = Op;};Path path;/** backup backend used to create execution when desinated backend do NOT support any op */MNNForwardType backupType = MNN_FORWARD_CPU;/** extra backend config */BackendConfig* backendConfig = nullptr;
};

1.5 BackendConfig

// project/android/demo/app/includes/MNN/MNNForwardType.h
struct BackendConfig {enum MemoryMode {Memory_Normal = 0,Memory_High,Memory_Low};MemoryMode memory = Memory_Normal;enum PowerMode {Power_Normal = 0,Power_High,Power_Low};PowerMode power = Power_Normal;enum PrecisionMode {Precision_Normal = 0,Precision_High,Precision_Low};PrecisionMode precision = Precision_Normal;/** user defined context */void* sharedContext = nullptr;
};

   

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