Files
2026-07-13 13:33:03 +08:00

133 lines
3.7 KiB
Plaintext

//
// SoftmaxExecution.cu
// MNN
//
// Created by MNN on 2026/02/25.
// Copyright © 2026, Alibaba Group Holding Limited
//
#include "SoftmaxExecution.hpp"
#include "core/Macro.h"
#include "core/TensorUtils.hpp"
#include "backend/musa/core/MusaBackend.hpp"
#include <musa_runtime.h>
namespace MNN {
namespace MUSA {
// MUSA kernel for softmax operation
__global__ void SoftmaxKernel(const float* input, float* output, int outerCount, int depth, int innerCount) {
int outerIdx = blockIdx.x;
int innerIdx = threadIdx.x + blockIdx.y * blockDim.x;
if (outerIdx >= outerCount || innerIdx >= innerCount) return;
const float* inPtr = input + outerIdx * depth * innerCount;
float* outPtr = output + outerIdx * depth * innerCount;
// Find max value for numerical stability
float maxVal = -FLT_MAX;
for (int i = 0; i < depth; i++) {
float val = inPtr[i * innerCount + innerIdx];
if (val > maxVal) {
maxVal = val;
}
}
// Compute exp and sum
float sum = 0.0f;
for (int i = 0; i < depth; i++) {
float expVal = expf(inPtr[i * innerCount + innerIdx] - maxVal);
outPtr[i * innerCount + innerIdx] = expVal;
sum += expVal;
}
// Normalize
float invSum = 1.0f / sum;
for (int i = 0; i < depth; i++) {
outPtr[i * innerCount + innerIdx] *= invSum;
}
}
SoftmaxExecution::SoftmaxExecution(int axis, Backend* backend) : Execution(backend) {
auto musaBackend = static_cast<MusaBackend*>(backend);
mRuntime = musaBackend->getMusaRuntime();
mAxis = axis;
}
ErrorCode SoftmaxExecution::onResize(const std::vector<Tensor*>& inputs, const std::vector<Tensor*>& outputs) {
auto input = inputs[0];
auto shape = input->shape();
int dims = shape.size();
if (mAxis < 0) {
mAxis = dims + mAxis;
}
mOuterCount = 1;
for (int i = 0; i < mAxis; i++) {
mOuterCount *= shape[i];
}
mDepth = shape[mAxis];
mInnerCount = 1;
for (int i = mAxis + 1; i < dims; i++) {
mInnerCount *= shape[i];
}
return NO_ERROR;
}
ErrorCode SoftmaxExecution::onExecute(const std::vector<Tensor*>& inputs, const std::vector<Tensor*>& outputs) {
#ifdef LOG_VERBOSE
MNN_PRINT("start SoftmaxExecution onExecute...\n");
#endif
auto input = inputs[0]->deviceId();
auto output = outputs[0]->deviceId();
int threadsPerBlock = 256;
dim3 blockDim(threadsPerBlock);
dim3 gridDim(mOuterCount, (mInnerCount + threadsPerBlock - 1) / threadsPerBlock);
SoftmaxKernel<<<gridDim, blockDim>>>((const float*)input, (float*)output, mOuterCount, mDepth, mInnerCount);
// Check for kernel launch errors
musaError_t err = musaGetLastError();
if (err != musaSuccess) {
MNN_ERROR("MUSA Softmax kernel launch failed: %s\n", musaGetErrorString(err));
}
// Synchronize to ensure completion
mRuntime->device_sync();
#ifdef LOG_VERBOSE
MNN_PRINT("end SoftmaxExecution onExecute...\n");
#endif
return NO_ERROR;
}
// Creator for Softmax operations
class SoftmaxCreator : public MusaBackend::Creator {
public:
virtual Execution* onCreate(const std::vector<Tensor*>& inputs, const std::vector<Tensor*>& outputs,
const MNN::Op* op, Backend* backend) const override {
int axis = 1;
if (op->type() == OpType_Softmax) {
auto softmax = op->main_as_Softmax();
if (softmax != nullptr && softmax->axis() != -1) {
axis = softmax->axis();
}
return new SoftmaxExecution(axis, backend);
}
return nullptr;
}
};
MusaCreatorRegister<SoftmaxCreator> __SoftmaxExecution(OpType_Softmax);
} // namespace MUSA
} // namespace MNN