未验证 提交 63abd500 编写于 作者: X xingfeng01 提交者: GitHub

softmax reconstruction and optimization (#31821)

上级 8552a182
......@@ -13,7 +13,9 @@ See the License for the specific language governing permissions and
limitations under the License. */
#include "paddle/fluid/framework/op_registry.h"
#include "paddle/fluid/operators/amp/fp16_type_traits.h"
#include "paddle/fluid/operators/math/math_cuda_utils.h"
#include "paddle/fluid/operators/softmax_impl.cuh"
#include "paddle/fluid/operators/softmax_op.h"
#include "paddle/fluid/platform/cuda_device_function.h"
#ifdef PADDLE_WITH_HIP
......@@ -21,7 +23,6 @@ limitations under the License. */
#else
#include "paddle/fluid/platform/cudnn_helper.h"
#endif
#include "paddle/fluid/platform/gpu_launch_config.h"
namespace paddle {
namespace platform {
......@@ -37,288 +38,414 @@ using ScopedTensorDescriptor = platform::ScopedTensorDescriptor;
using DataLayout = platform::DataLayout;
using Tensor = framework::Tensor;
#define LAUNCH_SOFTMAX_WARP_FORWARD(Log2Elements) \
case Log2Elements: \
WarpSoftmaxForward<T, float, Log2Elements><<< \
blocks, threads, 0, ctx.cuda_device_context().stream()>>>( \
out_data, x->data<T>(), N, dim, dim); \
break;
#define LAUNCH_SOFTMAX_WARP_BACKWARD(Log2Elements) \
case Log2Elements: \
softmax_warp_backward<T, float, Log2Elements><<< \
blocks, threads, 0, ctx.cuda_device_context().stream()>>>( \
dx_data, mul_grad.data<T>(), out->data<T>(), N, dim, dim); \
break;
static inline int SizeOutAxis(const int axis, DDim dims) {
int size = 1;
for (int i = axis + 1; i < dims.size(); i++) {
size *= dims[i];
}
return size;
}
int log2_ceil(int value) {
int log2_value = 0;
while ((1 << log2_value) < value) ++log2_value;
return log2_value;
}
template <typename T, int VLEN>
union vec_t {
static_assert(sizeof(T) == -1, "vec_t is only available by specialization.");
// Vectorization trait 4 * sizeof(T)
template <typename T>
class VecT4 {};
template <>
class VecT4<double> {
public:
using Type = long4;
};
template <>
union vec_t<float, 4> {
float4 s;
float v[4];
class VecT4<float> {
public:
using Type = int4;
};
template <>
class VecT4<platform::float16> {
public:
using Type = int2;
};
// Vectorization trait 2 * sizeof(T)
template <typename T>
class VecT2 {};
template <>
union vec_t<platform::float16, 4> {
int2 s;
platform::float16 v[4];
class VecT2<double> {
public:
using Type = int4;
};
template <>
class VecT2<float> {
public:
using Type = int2;
};
template <>
class VecT2<platform::float16> {
public:
using Type = int;
};
template <typename T, typename VECT, int VPT, int WARP_PER_BLOCK>
__global__ void VecSoftmaxForward(T* dst, const T* src, const int batch_size,
const int softmax_ele) {
int offset = blockIdx.x * softmax_ele * WARP_PER_BLOCK;
int idx = threadIdx.x * VPT;
VECT buf = reinterpret_cast<const VECT*>(&src[offset + idx])[0];
T* bufp = reinterpret_cast<T*>(&buf);
float4 val4;
float* val4p = reinterpret_cast<float*>(&val4);
for (int i = 0; i < VPT; ++i) {
val4p[i] = static_cast<float>(bufp[i]);
}
float val = val4.x + val4.y + val4.z + val4.w;
float max_val = math::warpReduceMax<float>(
max(max(val4.x, val4.y), max(val4.z, val4.w)), 0xffffffff);
float4 tmp4 = make_float4(__expf(val4.x - max_val), __expf(val4.y - max_val),
__expf(val4.z - max_val), __expf(val4.w - max_val));
float* tmp4p = reinterpret_cast<float*>(&tmp4);
float invsum = 1.f / (math::warpReduceSum<float>(
tmp4.x + tmp4.y + tmp4.z + tmp4.w, 0xffffffff) +
1e-6f);
for (int i = 0; i < VPT; ++i) {
bufp[i] = static_cast<T>(tmp4p[i] * invsum);
}
reinterpret_cast<VECT*>(&dst[offset + idx])[0] = buf;
int static inline log2_ceil(int value) {
int log2_value = 0;
while ((1 << log2_value) < value) ++log2_value;
return log2_value;
}
template <typename T, int WARP_BATCH, int WARP_SIZE_SOFTMAX>
__device__ __forceinline__ void warp_reduce_sum(T* sum) {
/*
Core function of computing softmax forward for axis=-1.
The computation includes
- Compute maximum of batch: maxvalue_{i} = max_j src_{i,j}
- Compute sum of exp batch: s_{i} = sum_{j}{ exp(src_{i,j} - maxvalue_{i} }
- Compute: (a_{i,j} - maxvalue_{i}) / s_{i}
One warp (32 threads) is used to compute 1 or 2 batch (kBatchSize).
For reduction max (sum), firstly compute max (sum) to one warp, then use shuffle
api to compute max (sum) in one warp.
*/
template <typename T, typename VecT, typename AccT, int Log2Elements,
bool LogMode = false>
__global__ void WarpSoftmaxForward(T* softmax, const T* src,
const int batch_size, const int stride,
const int element_count) {
constexpr int kDimCeil = 1 << Log2Elements;
constexpr int kWarpSize = (kDimCeil < 32) ? kDimCeil : 32;
constexpr int kVSize = sizeof(VecT) / sizeof(T);
constexpr int kIterations = kDimCeil / kWarpSize;
constexpr int kIterationsV =
(kIterations >= kVSize) ? (kIterations / kVSize) : 1;
constexpr int kBatchSize = (kDimCeil <= 32) ? 2 : 1;
int first_batch = (blockDim.y * blockIdx.x + threadIdx.y) * kBatchSize;
// max index to read
int idx_max_v[kBatchSize];
#pragma unroll
for (int offset = WARP_SIZE_SOFTMAX / 2; offset > 0; offset /= 2) {
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
T sum_val = platform::CudaShuffleXorSync(0xFFFFFFFF, sum[i], offset);
sum[i] = sum[i] + sum_val;
}
for (int i = 0; i < kBatchSize; i++) {
int idx_max = ((i + first_batch) < batch_size) ? element_count : 0;
idx_max_v[i] = idx_max / kVSize;
}
}
template <typename T, int WARP_BATCH, int WARP_SIZE_SOFTMAX>
__device__ __forceinline__ void warp_reduce_max(T* sum) {
// read data from global memory
AccT srcdata[kBatchSize][kIterationsV][kVSize];
#pragma unroll
for (int i = 0; i < kBatchSize; ++i) {
// read data
#pragma unroll
for (int it = 0; it < kIterationsV; ++it) {
int src_idx = threadIdx.x + it * kWarpSize;
if (kVSize == 1) {
if (src_idx < idx_max_v[i]) {
srcdata[i][it][0] =
static_cast<AccT>(src[(first_batch + i) * stride + src_idx]);
} else {
srcdata[i][it][0] = -std::numeric_limits<AccT>::infinity();
}
} else {
const VecT* src_v =
reinterpret_cast<const VecT*>(&src[(first_batch + i) * stride]);
if (src_idx < idx_max_v[i]) {
VecT srctmp = src_v[src_idx];
const T* srcinptr = reinterpret_cast<const T*>(&srctmp);
#pragma unroll
for (int offset = WARP_SIZE_SOFTMAX / 2; offset > 0; offset /= 2) {
for (int s = 0; s < kVSize; s++) {
srcdata[i][it][s] = static_cast<AccT>(srcinptr[s]);
}
} else {
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
T max_val = platform::CudaShuffleXorSync(0xFFFFFFFF, sum[i], offset);
sum[i] = max(sum[i], max_val);
for (int s = 0; s < kVSize; s++) {
srcdata[i][it][s] = -std::numeric_limits<AccT>::infinity();
}
}
}
}
}
}
template <typename T, typename AccT, int Log2Elements>
__global__ void WarpSoftmaxForward(T* dst, const T* src, const int batch_size,
const int stride, const int element_count) {
constexpr int next_power_of_two = 1 << Log2Elements;
constexpr int warp_size_softmax =
(next_power_of_two < 32) ? next_power_of_two : 32;
constexpr int WARP_ITERATIONS = next_power_of_two / warp_size_softmax;
constexpr int WARP_BATCH = (next_power_of_two <= 128) ? 2 : 1;
int first_batch = (blockDim.y * blockIdx.x + threadIdx.y) * WARP_BATCH;
int local_batches = batch_size - first_batch;
if (local_batches > WARP_BATCH) {
local_batches = WARP_BATCH;
}
int local_idx = threadIdx.x;
src += first_batch * stride + local_idx;
dst += first_batch * stride + local_idx;
// compute max value
AccT max_value[kBatchSize];
#pragma unroll
for (int i = 0; i < kBatchSize; ++i) {
// it = 0
AccT valmax = srcdata[i][0][0];
#pragma unroll
for (int s = 1; s < kVSize; ++s) {
valmax = (valmax > srcdata[i][0][s]) ? valmax : srcdata[i][0][s];
}
max_value[i] = valmax;
// load data from global memory
AccT elements[WARP_BATCH][WARP_ITERATIONS];
for (int i = 0; i < WARP_BATCH; ++i) {
int batch_element_count = (i >= local_batches) ? 0 : element_count;
for (int it = 0; it < WARP_ITERATIONS; ++it) {
int element_index = local_idx + it * warp_size_softmax;
if (element_index < batch_element_count) {
elements[i][it] =
static_cast<float>(src[i * element_count + it * warp_size_softmax]);
} else {
elements[i][it] = -std::numeric_limits<AccT>::infinity();
// it = 1, 2, ...
#pragma unroll
for (int it = 1; it < kIterationsV; ++it) {
AccT valmax = srcdata[i][it][0];
#pragma unroll
for (int s = 1; s < kVSize; ++s) {
valmax = (valmax > srcdata[i][it][s]) ? valmax : srcdata[i][it][s];
}
max_value[i] = (max_value[i] > valmax) ? max_value[i] : valmax;
}
}
WarpReduceMax<AccT, kBatchSize, kWarpSize>(max_value);
// compute max_value
AccT max_value[WARP_BATCH];
// compute sum
AccT sum[kBatchSize];
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
max_value[i] = elements[i][0];
for (int i = 0; i < kBatchSize; ++i) {
// it = 0
if (LogMode) {
sum[i] = std::exp(srcdata[i][0][0] - max_value[i]);
} else {
srcdata[i][0][0] = std::exp(srcdata[i][0][0] - max_value[i]);
sum[i] = srcdata[i][0][0];
}
#pragma unroll
for (int it = 1; it < WARP_ITERATIONS; ++it) {
max_value[i] =
(max_value[i] > elements[i][it]) ? max_value[i] : elements[i][it];
for (int s = 1; s < kVSize; ++s) {
if (LogMode) {
sum[i] += std::exp(srcdata[i][0][s] - max_value[i]);
} else {
srcdata[i][0][s] = std::exp(srcdata[i][0][s] - max_value[i]);
sum[i] += srcdata[i][0][s];
}
}
}
warp_reduce_max<AccT, WARP_BATCH, warp_size_softmax>(max_value);
AccT sum[WARP_BATCH]{0.0f};
// it = 1, 2, ...
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
for (int it = 1; it < kIterationsV; ++it) {
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; ++it) {
elements[i][it] = (std::exp((elements[i][it] - max_value[i])));
sum[i] += elements[i][it];
for (int s = 0; s < kVSize; ++s) {
if (LogMode) {
sum[i] += std::exp(srcdata[i][it][s] - max_value[i]);
} else {
srcdata[i][it][s] = std::exp(srcdata[i][it][s] - max_value[i]);
sum[i] += srcdata[i][it][s];
}
}
}
}
warp_reduce_sum<AccT, WARP_BATCH, warp_size_softmax>(sum);
WarpReduceSum<AccT, kBatchSize, kWarpSize>(sum);
// store result
// write result to global memory
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
if (i >= local_batches) break;
for (int i = 0; i < kBatchSize; ++i) {
if (LogMode) {
sum[i] = std::log(sum[i]);
}
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; ++it) {
int element_index = local_idx + it * warp_size_softmax;
if (element_index < element_count) {
dst[i * element_count + it * warp_size_softmax] =
elements[i][it] / sum[i];
for (int it = 0; it < kIterationsV; ++it) {
int idx = threadIdx.x + it * kWarpSize;
if (kVSize == 1) {
if (idx < idx_max_v[i]) {
if (LogMode) {
softmax[(first_batch + i) * stride + idx] =
srcdata[i][it][0] - max_value[i] - sum[i];
} else {
softmax[(first_batch + i) * stride + idx] =
srcdata[i][it][0] / sum[i];
}
} else {
break;
}
} else {
break;
VecT* softmax_v =
reinterpret_cast<VecT*>(&softmax[(first_batch + i) * stride]);
VecT tmpdata;
T* tmpptr = reinterpret_cast<T*>(&tmpdata);
#pragma unroll
for (int s = 0; s < kVSize; ++s) {
if (LogMode) {
tmpptr[s] = srcdata[i][it][s] - max_value[i] - sum[i];
} else {
tmpptr[s] = srcdata[i][it][s] / sum[i];
}
}
if (idx < idx_max_v[i]) {
softmax_v[idx] = tmpdata;
} else {
break;
}
}
}
}
}
template <typename T, typename AccT, int Log2Elements>
__global__ void softmax_warp_backward(T* gradInput, const T* grad,
const T* output, int batch_size,
int stride, int element_count) {
constexpr int next_power_of_two = 1 << Log2Elements;
constexpr int warp_size_softmax =
(next_power_of_two < 32) ? next_power_of_two : 32;
constexpr int WARP_ITERATIONS = next_power_of_two / warp_size_softmax;
constexpr int WARP_BATCH = (next_power_of_two <= 128) ? 2 : 1;
int first_batch = (blockDim.y * blockIdx.x + threadIdx.y) * WARP_BATCH;
/*
Core function of computing softmax backward for axis=-1.
The computation includes
- Compute sum of exp batch: s_{i} = sum_{j} {src_{i,j} * grad_{i,j}
- Compute src_{i,j} * ( grad_{i,j}) - s_{i} )
One warp (32 threads) is used to compute 1 or 2 batch (kBatchSize).
For reduction max (sum), firstly compute max (sum) to one warp, then use shuffle
api to compute max (sum) in one warp.
*/
template <typename T, typename VecT, typename AccT, int Log2Elements,
bool LogMode = false>
__global__ void WarpSoftmaxBackward(T* dst, const T* grad, const T* src,
int batch_size, int stride,
int element_count) {
constexpr int kVSize = sizeof(VecT) / sizeof(T);
constexpr int kDimCeil = 1 << Log2Elements;
constexpr int kWarpSize = (kDimCeil < 32) ? kDimCeil : 32;
constexpr int kIterations = kDimCeil / kWarpSize;
constexpr int kBatchSize = (kDimCeil <= 128) ? 2 : 1;
constexpr int kIterationsV =
(kIterations >= kVSize) ? (kIterations / kVSize) : 1;
int element_count_v = element_count / kVSize;
int first_batch = (blockDim.y * blockIdx.x + threadIdx.y) * kBatchSize;
int local_batches = batch_size - first_batch;
if (local_batches > WARP_BATCH) {
local_batches = WARP_BATCH;
if (local_batches > kBatchSize) {
local_batches = kBatchSize;
}
int local_idx = threadIdx.x % warp_size_softmax;
int thread_offset = first_batch * stride + local_idx;
grad += thread_offset;
output += thread_offset;
gradInput += thread_offset;
// load data from global memory
AccT grad_reg[WARP_BATCH][WARP_ITERATIONS];
AccT output_reg[WARP_BATCH][WARP_ITERATIONS];
for (int i = 0; i < WARP_BATCH; ++i) {
int batch_element_count = (i >= local_batches) ? 0 : element_count;
for (int it = 0; it < WARP_ITERATIONS; ++it) {
int element_index = local_idx + it * warp_size_softmax;
if (element_index < batch_element_count) {
grad_reg[i][it] =
static_cast<AccT>(grad[i * element_count + it * warp_size_softmax]);
output_reg[i][it] = static_cast<AccT>(
output[i * element_count + it * warp_size_softmax]);
// read data from global memory
VecT src_reg[kBatchSize][kIterationsV];
VecT grad_reg[kBatchSize][kIterationsV];
for (int i = 0; i < kBatchSize; ++i) {
const VecT* src_v =
reinterpret_cast<const VecT*>(&src[(first_batch + i) * stride]);
const VecT* grad_v =
reinterpret_cast<const VecT*>(&grad[(first_batch + i) * stride]);
// max index to read
int idx_max = (i < local_batches) ? element_count : 0;
int idx_max_v = idx_max / kVSize;
// read data
for (int it = 0; it < kIterationsV; ++it) {
int src_idx = threadIdx.x + it * kWarpSize;
if (src_idx < idx_max_v) {
src_reg[i][it] = src_v[src_idx];
grad_reg[i][it] = grad_v[src_idx];
} else {
grad_reg[i][it] = AccT(0);
output_reg[i][it] = AccT(0);
#pragma unroll
for (int s = 0; s < kVSize; s++) {
reinterpret_cast<T*>(&src_reg[i][it])[s] = 0.0;
reinterpret_cast<T*>(&grad_reg[i][it])[s] = 0.0;
}
}
}
}
AccT sum[WARP_BATCH];
// compute sum
AccT sum[kBatchSize]{0.0};
#pragma unroll
for (int i = 0; i < kBatchSize; ++i) {
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
sum[i] = grad_reg[i][0];
for (int it = 0; it < kIterationsV; ++it) {
T* gradptr = reinterpret_cast<T*>(&grad_reg[i][it]);
T* srcptr = reinterpret_cast<T*>(&src_reg[i][it]);
#pragma unroll
for (int it = 1; it < WARP_ITERATIONS; ++it) {
sum[i] += grad_reg[i][it];
for (int s = 0; s < kVSize; ++s) {
if (LogMode) {
sum[i] += static_cast<AccT>(gradptr[s]);
} else {
sum[i] += static_cast<AccT>(gradptr[s] * srcptr[s]);
}
}
}
}
warp_reduce_sum<AccT, WARP_BATCH, warp_size_softmax>(sum);
WarpReduceSum<AccT, kBatchSize, kWarpSize>(sum);
// store result
// write result
#pragma unroll
for (int i = 0; i < WARP_BATCH; ++i) {
for (int i = 0; i < kBatchSize; ++i) {
if (i >= local_batches) break;
VecT* dst_v = reinterpret_cast<VecT*>(&dst[(first_batch + i) * stride]);
// max index to write
int idx_max = (i < local_batches) ? element_count : 0;
int idx_max_v = idx_max / kVSize;
#pragma unroll
for (int it = 0; it < WARP_ITERATIONS; ++it) {
int element_index = local_idx + it * warp_size_softmax;
if (element_index < element_count) {
// compute gradients
gradInput[i * element_count + it * warp_size_softmax] =
(grad_reg[i][it] - output_reg[i][it] * sum[i]);
for (int it = 0; it < kIterationsV; ++it) {
VecT tmpdata;
T* tmpptr = reinterpret_cast<T*>(&tmpdata);
T* gradptr = reinterpret_cast<T*>(&grad_reg[i][it]);
T* srcptr = reinterpret_cast<T*>(&src_reg[i][it]);
#pragma unroll
for (int s = 0; s < kVSize; ++s) {
if (LogMode) {
tmpptr[s] = static_cast<AccT>(gradptr[s]) -
std::exp(static_cast<AccT>(srcptr[s])) * sum[i];
} else {
tmpptr[s] = static_cast<AccT>(srcptr[s]) *
(static_cast<AccT>(gradptr[s]) - sum[i]);
}
}
int idx = threadIdx.x + it * kWarpSize;
if (idx < idx_max_v) {
dst_v[idx] = tmpdata;
}
}
}
}
template <typename T>
__global__ void MultiplyCUDAKernel(T* C, const T* A, const T* B, int N) {
CUDA_KERNEL_LOOP(i, N) {
C[i] = static_cast<T>(static_cast<float>(A[i]) * static_cast<float>(B[i]));
#define SOFTMAX_WARP_FORWARD_CASE(Log2Elements, AccT) \
case Log2Elements: \
WarpSoftmaxForward< \
T, VecT, AccT, Log2Elements, \
LogMode><<<blocks, threads, 0, ctx.cuda_device_context().stream()>>>( \
dst, src, batch_size, stride, element_count); \
break;
/*
Wrapper of softmax formward with template instantiation on size of input.
*/
template <typename T, typename VecT, bool LogMode>
void SwitchWarpSoftmaxForward(const int blocks, const dim3 threads,
const framework::ExecutionContext& ctx, T* dst,
const T* src, const int batch_size,
const int stride, const int element_count,
int Log2Elements) {
using AccT = typename details::MPTypeTrait<T>::Type;
switch (Log2Elements) {
SOFTMAX_WARP_FORWARD_CASE(0, AccT);
SOFTMAX_WARP_FORWARD_CASE(1, AccT);
SOFTMAX_WARP_FORWARD_CASE(2, AccT);
SOFTMAX_WARP_FORWARD_CASE(3, AccT);
SOFTMAX_WARP_FORWARD_CASE(4, AccT);
SOFTMAX_WARP_FORWARD_CASE(5, AccT);
SOFTMAX_WARP_FORWARD_CASE(6, AccT);
SOFTMAX_WARP_FORWARD_CASE(7, AccT);
SOFTMAX_WARP_FORWARD_CASE(8, AccT);
SOFTMAX_WARP_FORWARD_CASE(9, AccT);
default:
break;
}
}
template <typename T, int VPT, int WARP_PER_BLOCK>
__global__ void VecSoftmaxBackward(T* dst, const T* grad, const T* src,
const int batch_size,
const int softmax_ele) {
const int offset =
blockIdx.x * softmax_ele * WARP_PER_BLOCK + threadIdx.x * VPT;
float local_sum_gy = 0.f;
vec_t<T, VPT> local_grad;
vec_t<T, VPT> local_src;
local_grad.s =
reinterpret_cast<const decltype(local_grad.s)*>(&grad[offset])[0];
local_src.s = reinterpret_cast<const decltype(local_src.s)*>(&src[offset])[0];
for (int i = 0; i < VPT; ++i) {
local_sum_gy += static_cast<float>(local_grad.v[i]) *
static_cast<float>(local_src.v[i]);
}
float sum_gy = math::warpReduceSum<float>(local_sum_gy, 0xffffffff);
#define SOFTMAX_WARP_BACKWARD_CASE(Log2Elements, AccT) \
case Log2Elements: \
WarpSoftmaxBackward< \
T, VecT, AccT, Log2Elements, \
LogMode><<<blocks, threads, 0, ctx.cuda_device_context().stream()>>>( \
dst, grad, src, batch_size, stride, element_count); \
break;
vec_t<T, VPT> local_dst;
for (int i = 0; i < VPT; ++i) {
local_dst.v[i] =
static_cast<T>(static_cast<float>(local_src.v[i]) *
(static_cast<float>(local_grad.v[i]) - sum_gy));
/*
Wrapper of softmax backward with template instantiation on size of input.
*/
template <typename T, typename VecT, bool LogMode>
void SwitchWarpSoftmaxBackward(const int blocks, const dim3 threads,
const framework::ExecutionContext& ctx, T* dst,
const T* grad, const T* src,
const int batch_size, const int stride,
const int element_count, int Log2Elements) {
using AccT = typename details::MPTypeTrait<T>::Type;
switch (Log2Elements) {
SOFTMAX_WARP_BACKWARD_CASE(0, AccT);
SOFTMAX_WARP_BACKWARD_CASE(1, AccT);
SOFTMAX_WARP_BACKWARD_CASE(2, AccT);
SOFTMAX_WARP_BACKWARD_CASE(3, AccT);
SOFTMAX_WARP_BACKWARD_CASE(4, AccT);
SOFTMAX_WARP_BACKWARD_CASE(5, AccT);
SOFTMAX_WARP_BACKWARD_CASE(6, AccT);
SOFTMAX_WARP_BACKWARD_CASE(7, AccT);
SOFTMAX_WARP_BACKWARD_CASE(8, AccT);
SOFTMAX_WARP_BACKWARD_CASE(9, AccT);
default:
break;
}
reinterpret_cast<decltype(local_dst.s)*>(&dst[offset])[0] = local_dst.s;
}
template <typename T>
#undef SOFTMAX_WARP_FORWARD_CASE
#undef SOFTMAX_WARP_BACKWARD_CASE
template <typename T, bool LogMode = false>
class SoftmaxCUDNNKernel : public framework::OpKernel<T> {
public:
void Compute(const framework::ExecutionContext& ctx) const override {
......@@ -335,60 +462,39 @@ class SoftmaxCUDNNKernel : public framework::OpKernel<T> {
const int D = SizeOutAxis(axis, dims);
constexpr int max_dim = 320;
bool optimize = false;
constexpr int warps_per_block = 4;
if (D == 1 && dim <= max_dim && sizeof(T) <= 4) {
if (dim == 128 && N % warps_per_block == 0) {
optimize = true;
// a warp for a batch, 4 elements for a thread, only support the softmax
// dim size = 128 currently
if (sizeof(T) == 2) {
VecSoftmaxForward<T, int2, 4, warps_per_block><<<
N / warps_per_block, warps_per_block * WARP_SIZE, 0,
ctx.cuda_device_context().stream()>>>(out_data, x->data<T>(), N,
dim);
} else if (sizeof(T) == 4) {
VecSoftmaxForward<T, int4, 4, warps_per_block><<<
N / warps_per_block, warps_per_block * WARP_SIZE, 0,
ctx.cuda_device_context().stream()>>>(out_data, x->data<T>(), N,
dim);
} else {
assert(false && "not support");
}
} else if (dim < max_dim) {
optimize = true;
int log2_elements = static_cast<int>(log2_ceil(dim));
const int next_power_of_two = 1 << log2_elements;
int warp_size = (next_power_of_two < 32) ? next_power_of_two : 32;
int batches_per_warp = (next_power_of_two <= 128) ? 2 : 1;
// use 128 threads per block to maximimize gpu utilization
constexpr int threads_per_block = 128;
int warps_per_block = (threads_per_block / warp_size);
int batches_per_block = warps_per_block * batches_per_warp;
int blocks = (N + batches_per_block - 1) / batches_per_block;
dim3 threads(warp_size, warps_per_block, 1);
switch (log2_elements) {
LAUNCH_SOFTMAX_WARP_FORWARD(0); // 1
LAUNCH_SOFTMAX_WARP_FORWARD(1); // 2
LAUNCH_SOFTMAX_WARP_FORWARD(2); // 4
LAUNCH_SOFTMAX_WARP_FORWARD(3); // 8
LAUNCH_SOFTMAX_WARP_FORWARD(4); // 16
LAUNCH_SOFTMAX_WARP_FORWARD(5); // 32
LAUNCH_SOFTMAX_WARP_FORWARD(6); // 64
LAUNCH_SOFTMAX_WARP_FORWARD(7); // 128
LAUNCH_SOFTMAX_WARP_FORWARD(8); // 256
LAUNCH_SOFTMAX_WARP_FORWARD(9); // 512
default:
break;
}
const int kDimLog2 = static_cast<int>(log2_ceil(dim));
const int kDimCeil = 1 << kDimLog2;
int kWarpSize = (kDimCeil < 32) ? kDimCeil : 32;
int batches_per_warp = (kDimCeil <= 32) ? 2 : 1;
// use 128 threads per block to maximimize gpu utilization
constexpr int threads_per_block = 128;
int warps_per_block = (threads_per_block / kWarpSize);
int batches_per_block = warps_per_block * batches_per_warp;
int blocks = (N + batches_per_block - 1) / batches_per_block;
dim3 threads(kWarpSize, warps_per_block, 1);
// vectorization read/write
using T4 = typename VecT4<T>::Type;
using T2 = typename VecT2<T>::Type;
if (dim % 4 == 0) {
SwitchWarpSoftmaxForward<T, T4, LogMode>(blocks, threads, ctx, out_data,
x->data<T>(), N, dim, dim,
kDimLog2);
} else if (dim % 2 == 0) {
SwitchWarpSoftmaxForward<T, T2, LogMode>(blocks, threads, ctx, out_data,
x->data<T>(), N, dim, dim,
kDimLog2);
} else {
SwitchWarpSoftmaxForward<T, T, LogMode>(blocks, threads, ctx, out_data,
x->data<T>(), N, dim, dim,
kDimLog2);
}
}
if (!optimize) {
} else {
ScopedTensorDescriptor desc;
std::vector<int> tensor_dims = {N, dim, D, 1};
DataLayout layout = DataLayout::kNCHW;
......@@ -405,22 +511,37 @@ class SoftmaxCUDNNKernel : public framework::OpKernel<T> {
#ifdef PADDLE_WITH_HIP
auto mode = axis == rank - 1 ? MIOPEN_SOFTMAX_MODE_INSTANCE
: MIOPEN_SOFTMAX_MODE_CHANNEL;
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::miopenSoftmaxForward(
handle, platform::CudnnDataType<T>::kOne(), desc_, x->data<T>(),
platform::CudnnDataType<T>::kZero(), desc_, out_data));
if (LogMode) {
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::miopenSoftmaxForward_V2(
handle, platform::CudnnDataType<T>::kOne(), desc_, x->data<T>(),
platform::CudnnDataType<T>::kZero(), desc_, out_data,
MIOPEN_SOFTMAX_LOG, mode));
} else {
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::miopenSoftmaxForward_V2(
handle, platform::CudnnDataType<T>::kOne(), desc_, x->data<T>(),
platform::CudnnDataType<T>::kZero(), desc_, out_data,
MIOPEN_SOFTMAX_ACCURATE, mode));
}
#else
auto mode = axis == rank - 1 ? CUDNN_SOFTMAX_MODE_INSTANCE
: CUDNN_SOFTMAX_MODE_CHANNEL;
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::cudnnSoftmaxForward(
handle, CUDNN_SOFTMAX_ACCURATE, mode,
platform::CudnnDataType<T>::kOne(), desc_, x->data<T>(),
platform::CudnnDataType<T>::kZero(), desc_, out_data));
if (LogMode) {
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::cudnnSoftmaxForward(
handle, CUDNN_SOFTMAX_LOG, mode, platform::CudnnDataType<T>::kOne(),
desc_, x->data<T>(), platform::CudnnDataType<T>::kZero(), desc_,
out_data));
} else {
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::cudnnSoftmaxForward(
handle, CUDNN_SOFTMAX_ACCURATE, mode,
platform::CudnnDataType<T>::kOne(), desc_, x->data<T>(),
platform::CudnnDataType<T>::kZero(), desc_, out_data));
}
#endif
}
}
};
template <typename T>
template <typename T, bool LogMode = false>
class SoftmaxGradCUDNNKernel : public framework::OpKernel<T> {
public:
void Compute(const framework::ExecutionContext& ctx) const override {
......@@ -437,78 +558,38 @@ class SoftmaxGradCUDNNKernel : public framework::OpKernel<T> {
const int N = SizeToAxis(axis, dims);
const int D = SizeOutAxis(axis, dims);
constexpr int max_dim = 320;
constexpr int warps_per_block = 4;
constexpr bool warp_softmax_available =
std::is_same<T, float>::value ||
std::is_same<T, platform::float16>::value;
bool optimize = false;
if (D == 1 && warp_softmax_available) {
if (dim == 128 && N % warps_per_block == 0) {
optimize = true;
if (std::is_same<T, float>::value) {
VecSoftmaxBackward<float, 4, warps_per_block><<<
N / warps_per_block, warps_per_block * WARP_SIZE, 0,
ctx.cuda_device_context().stream()>>>(dx->data<float>(),
dout->data<float>(),
out->data<float>(), N, dim);
} else if (std::is_same<T, platform::float16>::value) {
VecSoftmaxBackward<platform::float16, 4, warps_per_block><<<
N / warps_per_block, warps_per_block * WARP_SIZE, 0,
ctx.cuda_device_context().stream()>>>(
dx->data<platform::float16>(), dout->data<platform::float16>(),
out->data<platform::float16>(), N, dim);
} else {
PADDLE_ENFORCE_EQ(
warp_softmax_available, true,
platform::errors::Unimplemented(
"Warp softmax backward is only available for fp32 and fp16"));
}
} else if (dim < 40 && dim % 32 != 0) {
optimize = true;
Tensor mul_grad;
int numel = N * dim;
mul_grad.mutable_data<T>({numel}, ctx.GetPlace());
auto stream = ctx.cuda_device_context().stream();
auto& dev_ctx =
ctx.template device_context<platform::CUDADeviceContext>();
auto config = GetGpuLaunchConfig1D(dev_ctx, numel);
MultiplyCUDAKernel<T><<<config.block_per_grid.x,
config.thread_per_block.x, 0, stream>>>(
mul_grad.data<T>(), dout->data<T>(), out->data<T>(), numel);
int log2_elements = log2_ceil(dim);
const int next_power_of_two = 1 << log2_elements;
int warp_size = (next_power_of_two < 32) ? next_power_of_two : 32;
int batches_per_warp = (next_power_of_two <= 128) ? 2 : 1;
constexpr int threads_per_block = 128;
int warps_per_block = (threads_per_block / warp_size);
int batches_per_block = warps_per_block * batches_per_warp;
int blocks = (N + batches_per_block - 1) / batches_per_block;
dim3 threads(warp_size, warps_per_block, 1);
switch (log2_elements) {
LAUNCH_SOFTMAX_WARP_BACKWARD(0); // 1
LAUNCH_SOFTMAX_WARP_BACKWARD(1); // 2
LAUNCH_SOFTMAX_WARP_BACKWARD(2); // 4
LAUNCH_SOFTMAX_WARP_BACKWARD(3); // 8
LAUNCH_SOFTMAX_WARP_BACKWARD(4); // 16
LAUNCH_SOFTMAX_WARP_BACKWARD(5); // 32
LAUNCH_SOFTMAX_WARP_BACKWARD(6); // 64
LAUNCH_SOFTMAX_WARP_BACKWARD(7); // 128
LAUNCH_SOFTMAX_WARP_BACKWARD(8); // 256
LAUNCH_SOFTMAX_WARP_BACKWARD(9); // 512
default:
break;
}
if (D == 1 && dim <= max_dim && sizeof(T) <= 4) {
const int kDimLog2 = log2_ceil(dim);
const int kDimCeil = 1 << kDimLog2;
int kWarpSize = (kDimCeil < 32) ? kDimCeil : 32;
int batches_per_warp = (kDimCeil <= 128) ? 2 : 1;
constexpr int threads_per_block = 128;
int warps_per_block = (threads_per_block / kWarpSize);
int batches_per_block = warps_per_block * batches_per_warp;
int blocks = (N + batches_per_block - 1) / batches_per_block;
dim3 threads(kWarpSize, warps_per_block, 1);
// vectorization read/write
using T4 = typename VecT4<T>::Type;
using T2 = typename VecT2<T>::Type;
if (dim % 4 == 0) {
SwitchWarpSoftmaxBackward<T, T4, LogMode>(
blocks, threads, ctx, dx_data, dout->data<T>(), out->data<T>(), N,
dim, dim, kDimLog2);
} else if (dim % 2 == 0) {
SwitchWarpSoftmaxBackward<T, T2, LogMode>(
blocks, threads, ctx, dx_data, dout->data<T>(), out->data<T>(), N,
dim, dim, kDimLog2);
} else {
SwitchWarpSoftmaxBackward<T, T, LogMode>(
blocks, threads, ctx, dx_data, dout->data<T>(), out->data<T>(), N,
dim, dim, kDimLog2);
}
}
if (!optimize) {
} else {
ScopedTensorDescriptor desc;
std::vector<int> tensor_dims = {N, dim, D, 1};
DataLayout layout = DataLayout::kNCHW;
......@@ -525,18 +606,32 @@ class SoftmaxGradCUDNNKernel : public framework::OpKernel<T> {
#ifdef PADDLE_WITH_HIP
auto mode = axis == rank - 1 ? MIOPEN_SOFTMAX_MODE_INSTANCE
: MIOPEN_SOFTMAX_MODE_CHANNEL;
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::miopenSoftmaxBackward(
handle, platform::CudnnDataType<T>::kOne(), desc_, out->data<T>(),
desc_, dout->data<T>(), platform::CudnnDataType<T>::kZero(), desc_,
dx_data));
if (LogMode) {
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::miopenSoftmaxBackward_V2(
handle, platform::CudnnDataType<T>::kOne(), desc_, out->data<T>(),
desc_, dout->data<T>(), platform::CudnnDataType<T>::kZero(), desc_,
dx_data, MIOPEN_SOFTMAX_LOG, mode));
} else {
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::miopenSoftmaxBackward_V2(
handle, platform::CudnnDataType<T>::kOne(), desc_, out->data<T>(),
desc_, dout->data<T>(), platform::CudnnDataType<T>::kZero(), desc_,
dx_data, MIOPEN_SOFTMAX_ACCURATE, mode));
}
#else
auto mode = axis == rank - 1 ? CUDNN_SOFTMAX_MODE_INSTANCE
: CUDNN_SOFTMAX_MODE_CHANNEL;
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::cudnnSoftmaxBackward(
handle, CUDNN_SOFTMAX_ACCURATE, mode,
platform::CudnnDataType<T>::kOne(), desc_, out->data<T>(), desc_,
dout->data<T>(), platform::CudnnDataType<T>::kZero(), desc_,
dx_data));
if (LogMode) {
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::cudnnSoftmaxBackward(
handle, CUDNN_SOFTMAX_LOG, mode, platform::CudnnDataType<T>::kOne(),
desc_, out->data<T>(), desc_, dout->data<T>(),
platform::CudnnDataType<T>::kZero(), desc_, dx_data));
} else {
PADDLE_ENFORCE_CUDA_SUCCESS(platform::dynload::cudnnSoftmaxBackward(
handle, CUDNN_SOFTMAX_ACCURATE, mode,
platform::CudnnDataType<T>::kOne(), desc_, out->data<T>(), desc_,
dout->data<T>(), platform::CudnnDataType<T>::kZero(), desc_,
dx_data));
}
#endif
}
}
......
/* Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. */
#pragma once
#include "paddle/fluid/platform/cuda_device_function.h"
namespace paddle {
namespace operators {
template <typename T, int BatchSize, int WarpSize>
__device__ __forceinline__ void WarpReduceSum(T* sum) {
#pragma unroll
for (int offset = WarpSize / 2; offset > 0; offset /= 2) {
#pragma unroll
for (int i = 0; i < BatchSize; ++i) {
T sum_val = platform::CudaShuffleXorSync(0xFFFFFFFF, sum[i], offset);
sum[i] = sum[i] + sum_val;
}
}
}
template <typename T, int BatchSize, int WarpSize>
__device__ __forceinline__ void WarpReduceMax(T* sum) {
#pragma unroll
for (int offset = WarpSize / 2; offset > 0; offset /= 2) {
#pragma unroll
for (int i = 0; i < BatchSize; ++i) {
T max_val = platform::CudaShuffleXorSync(0xFFFFFFFF, sum[i], offset);
sum[i] = max(sum[i], max_val);
}
}
}
} // namespace operators
} // namespace paddle
\ No newline at end of file
......@@ -45,6 +45,14 @@ static inline int SizeFromAxis(const int axis, DDim dims) {
return size;
}
static inline int SizeOutAxis(const int axis, DDim dims) {
int size = 1;
for (int i = axis + 1; i < dims.size(); i++) {
size *= dims[i];
}
return size;
}
template <typename DeviceContext, typename T>
class SoftmaxKernel : public framework::OpKernel<T> {
public:
......
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