Allow vectorized padding on GPU. This helps speed things up a little.

Before:
BM_padding/10            5000000        460   217.03 MFlops/s
BM_padding/80            5000000        460 13899.40 MFlops/s
BM_padding/640           5000000        461 888421.17 MFlops/s
BM_padding/4K            5000000        460 54316322.55 MFlops/s
After:
BM_padding/10            5000000        454   220.20 MFlops/s
BM_padding/80            5000000        455 14039.86 MFlops/s
BM_padding/640           5000000        452 904968.83 MFlops/s
BM_padding/4K            5000000        411 60750049.21 MFlops/s
This commit is contained in:
Benoit Steiner 2016-05-17 09:13:27 -07:00
parent a80d875916
commit 8d06c02ffd
4 changed files with 107 additions and 30 deletions

View File

@ -93,7 +93,7 @@ struct TensorEvaluator<const TensorPaddingOp<PaddingDimensions, ArgType>, Device
static const int PacketSize = internal::unpacket_traits<PacketReturnType>::size;
enum {
IsAligned = false,
IsAligned = true,
PacketAccess = TensorEvaluator<ArgType, Device>::PacketAccess,
Layout = TensorEvaluator<ArgType, Device>::Layout,
CoordAccess = true,

View File

@ -328,6 +328,9 @@ template <typename S, typename R, typename I>
__global__ void ReductionInitKernelHalfFloat(R, const S, I, half2*);
template <int B, int N, typename S, typename R, typename I>
__global__ void FullReductionKernelHalfFloat(R, const S, I, half*, half2*);
template <int NPT, typename S, typename R, typename I>
__global__ void InnerReductionKernelHalfFloat(R, const S, I, I, half*, half2*);
#endif
template <int NPT, typename S, typename R, typename I>
@ -629,11 +632,15 @@ struct TensorEvaluator<const TensorReductionOp<Op, Dims, ArgType>, Device>
#ifdef EIGEN_HAS_CUDA_FP16
template <typename S, typename R, typename I> friend void internal::ReductionInitKernelHalfFloat(R, const S, I, half2*);
template <int B, int N, typename S, typename R, typename I> friend void internal::FullReductionKernelHalfFloat(R, const S, I, half*, half2*);
template <int NPT, typename S, typename R, typename I> friend void internal::InnerReductionKernelHalfFloat(R, const S, I, I, half*, half2*);
#endif
template <int NPT, typename S, typename R, typename I> friend void internal::InnerReductionKernel(R, const S, I, I, typename S::CoeffReturnType*);
template <int NPT, typename S, typename R, typename I> friend void internal::OuterReductionKernel(R, const S, I, I, typename S::CoeffReturnType*);
#endif
template <typename S, typename O, typename D> friend struct internal::InnerReducer;
// Returns the Index in the input tensor of the first value that needs to be
// used to compute the reduction at output index "index".
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Index firstInput(Index index) const {

View File

@ -361,7 +361,7 @@ __global__ void InnerReductionKernel(Reducer reducer, const Self input, Index nu
}
#ifdef EIGEN_HAS_CUDA_FP16
/*
template <int NumPerThread, typename Self,
typename Reducer, typename Index>
__global__ void InnerReductionKernelHalfFloat(Reducer reducer, const Self input, Index num_coeffs_to_reduce, Index num_preserved_coeffs,
@ -375,7 +375,7 @@ __global__ void InnerReductionKernelHalfFloat(Reducer reducer, const Self input,
eigen_assert(NumPerThread % unroll_times == 0);
eigen_assert(unroll_times % 2 == 0);
const Index input_col_blocks = divup<Index>(num_coeffs_to_reduce, blockDim.x * NumPerThread);
const Index input_col_blocks = divup<Index>(num_coeffs_to_reduce, blockDim.x * NumPerThread/2);
const Index num_input_blocks = input_col_blocks * num_preserved_coeffs;
const Index num_threads = blockDim.x * gridDim.x;
@ -383,40 +383,44 @@ __global__ void InnerReductionKernelHalfFloat(Reducer reducer, const Self input,
// Initialize the output values if they weren't initialized by the ReductionInitKernel
if (gridDim.x == 1) {
Index i = thread_id;
for (; i < num_preserved_coeffs; i += 2*num_threads) {
((half2*)output)[i] = reducer.initializePacket();
Index i = 2*thread_id;
for (; i + 1 < num_preserved_coeffs; i += 2*num_threads) {
((half2*)output)[i] = reducer.template initializePacket<half2>();
}
if (i + 1 < num_preserved_coeffs) {
if (i < num_preserved_coeffs) {
output[i] = reducer.initialize();
}
__syncthreads();
}
for (Index i = blockIdx.x; i < num_input_blocks; i += gridDim.x) {
for (Index i = 2*blockIdx.x; i < num_input_blocks; i += 2*gridDim.x) {
const Index row = i / input_col_blocks;
if (row + 1 < num_preserved_coeffs) {
const Index col_block = i % input_col_blocks;
const Index col_begin = col_block * blockDim.x * NumPerThread + threadIdx.x;
half2 reduced_val1 = reducer.initializePacket();
half2 reduced_val2 = reducer.initializePacket();
half2 reduced_val1 = reducer.template initializePacket<half2>();
half2 reduced_val2 = reducer.template initializePacket<half2>();
for (Index j = 0; j < NumPerThread; j += unroll_times) {
const Index last_col = col_begin + blockDim.x * (j + unroll_times - 1);
if (last_col >= num_coeffs_to_reduce) {
Index col = col_begin + blockDim.x * j;
for (; col + 1 < num_coeffs_to_reduce; col += blockDim.x) {
const half2 val = input.m_impl.packet(row * num_coeffs_to_reduce + col);
reducer.reduce(val, &reduced_val);
// do the same for reduce val2 here
const half2 val1 = input.m_impl.template packet<Unaligned>(row * num_coeffs_to_reduce + col);
reducer.reducePacket(val1, &reduced_val1);
const half2 val2 = input.m_impl.template packet<Unaligned>((row+1) * num_coeffs_to_reduce + col);
reducer.reducePacket(val2, &reduced_val2);
}
if (col < num_coeffs_to_reduce) {
// Peel;
const half last = input.m_impl.coeff(row * num_coeffs_to_reduce + col+1);
const half2 val = __halves2half2(last, reducer.initialize());
reducer.reducePacket(val, &reduced_val);
const half last1 = input.m_impl.coeff(row * num_coeffs_to_reduce + col+1);
const half2 val1 = __halves2half2(last1, reducer.initialize());
reducer.reducePacket(val1, &reduced_val1);
const half last2 = input.m_impl.coeff((row+1) * num_coeffs_to_reduce + col+1);
const half2 val2 = __halves2half2(last2, reducer.initialize());
reducer.reducePacket(val2, &reduced_val2);
}
break;
} else {
@ -424,41 +428,44 @@ __global__ void InnerReductionKernelHalfFloat(Reducer reducer, const Self input,
#pragma unroll
for (int k = 0; k < unroll_times; ++k) {
const Index col = col_begin + blockDim.x * (j + k);
reducer.reduce(input.m_impl.packet(row * num_coeffs_to_reduce + col), &reduced_val);
reducer.reducePacket(input.m_impl.template packet<Unaligned>(row * num_coeffs_to_reduce + col), &reduced_val1);
reducer.reducePacket(input.m_impl.template packet<Unaligned>((row +1)* num_coeffs_to_reduce + col), &reduced_val2);
}
}
}
#pragma unroll
for (int offset = warpSize/2; offset > 0; offset /= 2) {
reducer.reducePacket(__shfl_down(reduced_val, offset, warpSize), &reduced_val);
reducer.reducePacket(__shfl_down(reduced_val1, offset, warpSize), &reduced_val1);
reducer.reducePacket(__shfl_down(reduced_val2, offset, warpSize), &reduced_val2);
}
half val1 = __low2half(reduced_val1);
reducer.reduce(__high2half(reduced_val1), &val1);
half val2 = __low2half(reduced_val2);
reducer.reduce(__high2half(reduced_val2), &val2);
half2 val = __halves2half2(val1, val2);
if ((threadIdx.x & (warpSize - 1)) == 0) {
if (row + 1 < num_preserved_coeffs) {
atomicReduce(&(output[row]), reduced_val, reducer);
}
else {
atomicReduce(scratch, reduced_val, reducer);
}
atomicReduce(&(((half2*)output)[row]), val, reducer);
}
}
}
}
*/
#endif
template <typename Self, typename Op>
struct InnerReducer<Self, Op, GpuDevice> {
struct InnerReductionLauncher {
// Unfortunately nvidia doesn't support well exotic types such as complex,
// so reduce the scope of the optimized version of the code to the simple case
// of floats.
static const bool HasOptimizedImplementation = !Op::IsStateful &&
internal::is_same<typename Self::CoeffReturnType, float>::value;
template <typename Device, typename OutputType>
static EIGEN_DEVICE_FUNC bool run(const Self&, Op&, const Device&, OutputType*, typename Self::Index, typename Self::Index) {
assert(false && "Should only be called to reduce floats on a gpu device");
template <typename OutputType>
static EIGEN_DEVICE_FUNC bool run(const Self&, Op&, const GpuDevice&, OutputType*, typename Self::Index, typename Self::Index) {
assert(false && "Should only be called to reduce floats and half floats on a gpu device");
return true;
}
@ -495,9 +502,72 @@ struct InnerReducer<Self, Op, GpuDevice> {
return false;
}
#ifdef EIGEN_HAS_CUDA_FP16
static bool run(const Self& self, Op& reducer, const GpuDevice& device, half* output, typename Self::Index num_coeffs_to_reduce, typename Self::Index num_preserved_vals) {
typedef typename Self::Index Index;
// It's faster to use the usual code.
if (num_coeffs_to_reduce <= 32) {
return true;
}
const Index num_coeffs = num_coeffs_to_reduce * num_preserved_vals;
const int block_size = 256;
const int num_per_thread = 128;
const int dyn_blocks = divup<int>(num_coeffs, block_size * num_per_thread);
const int max_blocks = device.getNumCudaMultiProcessors() *
device.maxCudaThreadsPerMultiProcessor() / block_size;
const int num_blocks = numext::mini<int>(max_blocks, dyn_blocks);
half2* scratch = static_cast<half2*>(device.scratchpad());
if (num_blocks > 1) {
// We initialize the outputs outside the reduction kernel when we can't be sure that there
// won't be a race conditions between multiple thread blocks.
const int dyn_blocks = divup<int>(num_preserved_vals, 1024);
const int max_blocks = device.getNumCudaMultiProcessors() *
device.maxCudaThreadsPerMultiProcessor() / 1024;
const int num_blocks = numext::mini<int>(max_blocks, dyn_blocks);
LAUNCH_CUDA_KERNEL((ReductionInitKernelHalfFloat<Self, Op, Index>),
1, 1, 0, device, reducer, self, num_preserved_vals, scratch);
}
LAUNCH_CUDA_KERNEL((InnerReductionKernelHalfFloat<num_per_thread, Self, Op, Index>),
num_blocks, block_size, 0, device, reducer, self, num_coeffs_to_reduce, num_preserved_vals, output, scratch);
return false;
}
#endif
};
template <typename Self, typename Op>
struct InnerReducer<Self, Op, GpuDevice> {
// Unfortunately nvidia doesn't support well exotic types such as complex,
// so reduce the scope of the optimized version of the code to the simple case
// of floats and half floats.
#ifdef EIGEN_HAS_CUDA_FP16
static const bool HasOptimizedImplementation = !Op::IsStateful &&
(internal::is_same<typename Self::CoeffReturnType, float>::value ||
internal::is_same<typename Self::CoeffReturnType, Eigen::half>::value);
#else
static const bool HasOptimizedImplementation = !Op::IsStateful &&
internal::is_same<typename Self::CoeffReturnType, float>::value;
#endif
template <typename OutputType>
static bool run(const Self& self, Op& reducer, const GpuDevice& device, OutputType* output, typename Self::Index num_coeffs_to_reduce, typename Self::Index num_preserved_vals) {
assert(HasOptimizedImplementation && "Should only be called on floats or half floats");
const Index num_coeffs = array_prod(self.m_impl.dimensions());
// Don't crash when we're called with an input tensor of size 0.
if (num_coeffs == 0) {
return true;
}
return InnerReductionLauncher<Self, Op>::run(self, reducer, device, output, num_coeffs_to_reduce, num_preserved_vals);
}
};
template <int NumPerThread, typename Self,
typename Reducer, typename Index>
__global__ void OuterReductionKernel(Reducer reducer, const Self input, Index num_coeffs_to_reduce, Index num_preserved_coeffs,

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@ -251,7 +251,7 @@ void test_cuda_contractions() {
void test_cuda_reductions() {
Eigen::CudaStreamDevice stream;
Eigen::GpuDevice gpu_device(&stream);
int size = 13;
int size = 40;
int num_elem = size*size;
float* d_float1 = (float*)gpu_device.allocate(num_elem * sizeof(float));