remove duplicate pset1 for half and add some comments about why we need expose pmul/add/div/min/max on host

This commit is contained in:
Sami Kama 2020-03-10 20:28:43 +00:00 committed by Rasmus Munk Larsen
parent a45d28256d
commit b733b8b680
5 changed files with 1069 additions and 167 deletions

File diff suppressed because it is too large Load Diff

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@ -17,12 +17,13 @@ namespace internal {
#if (defined(EIGEN_HAS_CUDA_FP16) && defined(EIGEN_CUDA_ARCH) && EIGEN_CUDA_ARCH >= 300) || \
(defined(EIGEN_HAS_HIP_FP16) && defined(EIGEN_HIP_DEVICE_COMPILE))
template <>
struct type_casting_traits<Eigen::half, float> {
enum {
VectorizedCast = 1,
SrcCoeffRatio = 2,
TgtCoeffRatio = 1
SrcCoeffRatio = 1,
TgtCoeffRatio = 2
};
};
@ -32,15 +33,39 @@ template<> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE float4 pcast<half2, float4>(con
return make_float4(r1.x, r1.y, r2.x, r2.y);
}
template<> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Packet4h2 pcast<float4, Packet4h2>(const float4& a, const float4& b) {
Packet4h2 r;
half2* r_alias=reinterpret_cast<half2*>(&r);
r_alias[0]=__floats2half2_rn(a.x,a.y);
r_alias[1]=__floats2half2_rn(a.z,a.w);
r_alias[2]=__floats2half2_rn(b.x,b.y);
r_alias[3]=__floats2half2_rn(b.z,b.w);
return r;
}
template <>
struct type_casting_traits<float, Eigen::half> {
enum {
VectorizedCast = 1,
SrcCoeffRatio = 1,
TgtCoeffRatio = 2
SrcCoeffRatio = 2,
TgtCoeffRatio = 1
};
};
template<> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE float4 pcast<Packet4h2, float4>(const Packet4h2& a) {
// Simply discard the second half of the input
float4 r;
const half2* a_alias=reinterpret_cast<const half2*>(&a);
float2 r1 = __half22float2(a_alias[0]);
float2 r2 = __half22float2(a_alias[1]);
r.x=static_cast<float>(r1.x);
r.y=static_cast<float>(r1.y);
r.z=static_cast<float>(r2.x);
r.w=static_cast<float>(r2.y);
return r;
}
template<> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE half2 pcast<float4, half2>(const float4& a) {
// Simply discard the second half of the input
return __floats2half2_rn(a.x, a.y);

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@ -53,10 +53,12 @@ struct PacketType : internal::packet_traits<Scalar> {
// For CUDA packet types when using a GpuDevice
#if defined(EIGEN_USE_GPU) && defined(EIGEN_HAS_GPU_FP16)
template <>
typedef ulonglong2 Packet4h2;
template<>
struct PacketType<half, GpuDevice> {
typedef half2 type;
static const int size = 2;
typedef Packet4h2 type;
static const int size = 8;
enum {
HasAdd = 1,
HasSub = 1,

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@ -420,9 +420,9 @@ __global__ void FullReductionKernel(R, const S, I_, typename S::CoeffReturnType*
#if defined(EIGEN_HAS_GPU_FP16)
template <typename S, typename R, typename I_>
__global__ void ReductionInitFullReduxKernelHalfFloat(R, const S, I_, half2*);
__global__ void ReductionInitFullReduxKernelHalfFloat(R, const S, I_, internal::packet_traits<half>::type*);
template <int B, int N, typename S, typename R, typename I_>
__global__ void FullReductionKernelHalfFloat(R, const S, I_, half*, half2*);
__global__ void FullReductionKernelHalfFloat(R, const S, I_, half*, internal::packet_traits<half>::type*);
template <int NPT, typename S, typename R, typename I_>
__global__ void InnerReductionKernelHalfFloat(R, const S, I_, I_, half*);
@ -863,8 +863,8 @@ struct TensorReductionEvaluatorBase<const TensorReductionOp<Op, Dims, ArgType, M
#if defined(EIGEN_USE_GPU) && (defined(EIGEN_GPUCC))
template <int B, int N, typename S, typename R, typename I_> KERNEL_FRIEND void internal::FullReductionKernel(R, const S, I_, typename S::CoeffReturnType*, unsigned int*);
#if defined(EIGEN_HAS_GPU_FP16)
template <typename S, typename R, typename I_> KERNEL_FRIEND void internal::ReductionInitFullReduxKernelHalfFloat(R, const S, I_, half2*);
template <int B, int N, typename S, typename R, typename I_> KERNEL_FRIEND void internal::FullReductionKernelHalfFloat(R, const S, I_, half*, half2*);
template <typename S, typename R, typename I_> KERNEL_FRIEND void internal::ReductionInitFullReduxKernelHalfFloat(R, const S, I_, internal::packet_traits<Eigen::half>::type*);
template <int B, int N, typename S, typename R, typename I_> KERNEL_FRIEND void internal::FullReductionKernelHalfFloat(R, const S, I_, half*, internal::packet_traits<Eigen::half>::type*);
template <int NPT, typename S, typename R, typename I_> KERNEL_FRIEND void internal::InnerReductionKernelHalfFloat(R, const S, I_, I_, half*);
#endif
template <int NPT, typename S, typename R, typename I_> KERNEL_FRIEND void internal::InnerReductionKernel(R, const S, I_, I_, typename S::CoeffReturnType*);

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@ -98,7 +98,17 @@ __device__ inline void atomicReduce(half2* output, half2 accum, R<half>& reducer
}
}
}
#endif // EIGEN_HAS_GPU_FP16
// reduction should be associative since reduction is not atomic in wide vector but atomic in half2 operations
template <template <typename T> class R>
__device__ inline void atomicReduce(Packet4h2* output, Packet4h2 accum,
R<half>& reducer) {
half2* houtput=reinterpret_cast<half2*>(output);
half2* haccum=reinterpret_cast<half2*>(&accum);
for(int i=0;i<4;++i){
atomicReduce(houtput+i,*(haccum+i),reducer);
}
}
#endif // EIGEN_HAS_GPU_FP16
template <>
__device__ inline void atomicReduce(float* output, float accum, SumReducer<float>&) {
@ -204,14 +214,26 @@ __global__ void FullReductionKernel(Reducer reducer, const Self input, Index num
#ifdef EIGEN_HAS_GPU_FP16
template <typename Self,
typename Reducer, typename Index>
__global__ void ReductionInitFullReduxKernelHalfFloat(Reducer reducer, const Self input, Index num_coeffs, half2* scratch) {
__global__ void ReductionInitFullReduxKernelHalfFloat(Reducer reducer, const Self input, Index num_coeffs,
packet_traits<Eigen::half>::type* scratch) {
eigen_assert(blockDim.x == 1);
eigen_assert(gridDim.x == 1);
if (num_coeffs % 2 != 0) {
half lastCoeff = input.m_impl.coeff(num_coeffs-1);
*scratch = __halves2half2(lastCoeff, reducer.initialize());
typedef packet_traits<Eigen::half>::type packet_type;
Index packet_remainder =
num_coeffs % Index(unpacket_traits<packet_type>::size);
if (packet_remainder != 0) {
half2* h2scratch = reinterpret_cast<half2*>(scratch);
for (Index i = num_coeffs - packet_remainder; i + 2 <= num_coeffs; i += 2) {
*h2scratch =
__halves2half2(input.m_impl.coeff(i), input.m_impl.coeff(i + 1));
h2scratch++;
}
if ((num_coeffs & 1) != 0) {
half lastCoeff = input.m_impl.coeff(num_coeffs - 1);
*h2scratch = __halves2half2(lastCoeff, reducer.initialize());
}
} else {
*scratch = reducer.template initializePacket<half2>();
*scratch = reducer.template initializePacket<packet_type>();
}
}
@ -220,44 +242,64 @@ template <typename Self,
__global__ void ReductionInitKernelHalfFloat(Reducer reducer, const Self input, Index num_coeffs, half* output) {
const Index thread_id = blockIdx.x * blockDim.x + threadIdx.x;
const Index num_threads = blockDim.x * gridDim.x;
const Index num_packets = num_coeffs / 2;
for (Index i = thread_id; i < num_packets; i += num_threads) {
((half2*)output)[i] = reducer.template initializePacket<half2>();
}
typedef typename packet_traits<Eigen::half>::type PacketType;
if (thread_id == 0 && num_coeffs % 2 != 0) {
output[num_coeffs-1] = reducer.initialize();
const Index num_packets =
num_coeffs / Index(unpacket_traits<PacketType>::size);
PacketType* p_output = reinterpret_cast<PacketType*>(output);
for (Index i = thread_id; i < num_packets; i += num_threads) {
p_output[i] = reducer.template initializePacket<PacketType>();
}
Index packet_remainder =
num_coeffs % Index(unpacket_traits<PacketType>::size);
if (thread_id < packet_remainder) {
output[num_coeffs - packet_remainder + thread_id] = reducer.initialize();
}
}
template <int BlockSize, int NumPerThread, typename Self,
typename Reducer, typename Index>
__global__ void FullReductionKernelHalfFloat(Reducer reducer, const Self input, Index num_coeffs,
half* output, half2* scratch) {
eigen_assert(NumPerThread % 2 == 0);
const Index first_index = blockIdx.x * BlockSize * NumPerThread + 2*threadIdx.x;
half* output, packet_traits<Eigen::half>::type* scratch) {
typedef typename packet_traits<Eigen::half>::type PacketType;
const int packet_width = unpacket_traits<PacketType>::size;
eigen_assert(NumPerThread % packet_width == 0);
const Index first_index =
blockIdx.x * BlockSize * NumPerThread + packet_width * threadIdx.x;
// Initialize the output value if it wasn't initialized by the ReductionInitKernel
if (gridDim.x == 1) {
if (first_index == 0) {
if (num_coeffs % 2 != 0) {
half last = input.m_impl.coeff(num_coeffs-1);
*scratch = __halves2half2(last, reducer.initialize());
int rem = num_coeffs % packet_width;
if (rem != 0) {
half2* p_scratch = reinterpret_cast<half2*>(scratch);
*scratch = reducer.template initializePacket<PacketType>();
for (int i = 0; i < rem / 2; i++) {
*p_scratch = __halves2half2(
input.m_impl.coeff(num_coeffs - packet_width + 2 * i),
input.m_impl.coeff(num_coeffs - packet_width + 2 * i + 1));
p_scratch++;
}
if ((num_coeffs & 1) != 0) {
half last = input.m_impl.coeff(num_coeffs - 1);
*p_scratch = __halves2half2(last, reducer.initialize());
}
} else {
*scratch = reducer.template initializePacket<half2>();
*scratch = reducer.template initializePacket<PacketType>();
}
}
__syncthreads();
}
half2 accum = reducer.template initializePacket<half2>();
const Index max_iter = numext::mini<Index>((num_coeffs - first_index) / 2, NumPerThread*BlockSize / 2);
PacketType accum = reducer.template initializePacket<PacketType>();
const Index max_iter =
numext::mini<Index>((num_coeffs - first_index) / packet_width,
NumPerThread * BlockSize / packet_width);
for (Index i = 0; i < max_iter; i += BlockSize) {
const Index index = first_index + 2*i;
eigen_assert(index + 1 < num_coeffs);
half2 val = input.m_impl.template packet<Unaligned>(index);
const Index index = first_index + packet_width * i;
eigen_assert(index + packet_width < num_coeffs);
PacketType val = input.m_impl.template packet<Unaligned>(index);
reducer.reducePacket(val, &accum);
}
@ -270,10 +312,22 @@ __global__ void FullReductionKernelHalfFloat(Reducer reducer, const Self input,
wka_out.i = __shfl_down(wka_in.i, offset, warpSize);
reducer.reducePacket(wka_out.h, &accum);
#elif defined(EIGEN_CUDA_SDK_VER) && EIGEN_CUDA_SDK_VER < 90000
reducer.reducePacket(__shfl_down(accum, offset, warpSize), &accum);
PacketType r1;
half2* hr = reinterpret_cast<half2*>(&r1);
half2* hacc = reinterpret_cast<half2*>(&accum);
for (int i = 0; i < packet_width / 2; i++) {
hr[i] = __shfl_down(hacc[i], offset, warpSize);
}
reducer.reducePacket(r1, &accum);
#else
int temp = __shfl_down_sync(0xFFFFFFFF, *(int*)(&accum), (unsigned)offset, warpSize);
reducer.reducePacket(*(half2*)(&temp), &accum);
PacketType r1;
half2* hr = reinterpret_cast<half2*>(&r1);
half2* hacc = reinterpret_cast<half2*>(&accum);
for (int i = 0; i < packet_width / 2; i++) {
hr[i] = __shfl_down_sync(0xFFFFFFFF, hacc[i], (unsigned)offset, warpSize);
}
reducer.reducePacket(r1, &accum);
#endif
}
@ -281,21 +335,33 @@ __global__ void FullReductionKernelHalfFloat(Reducer reducer, const Self input,
atomicReduce(scratch, accum, reducer);
}
__syncthreads();
half2* rv1 = reinterpret_cast<half2*>(scratch);
if (packet_width > 2) {
reducer.reducePacket(rv1[2], rv1);
reducer.reducePacket(rv1[3], rv1 + 1);
reducer.reducePacket(rv1[1], rv1);
}
if (gridDim.x == 1) {
__syncthreads();
if (first_index == 0) {
half tmp = __low2half(*scratch);
reducer.reduce(__high2half(*scratch), &tmp);
half tmp = __low2half(*rv1);
reducer.reduce(__high2half(*rv1), &tmp);
*output = tmp;
}
}
}
template <typename Op>
__global__ void ReductionCleanupKernelHalfFloat(Op reducer, half* output, half2* scratch) {
__global__ void ReductionCleanupKernelHalfFloat(Op reducer, half* output, packet_traits<Eigen::half>::type* scratch) {
eigen_assert(threadIdx.x == 1);
half tmp = __low2half(*scratch);
reducer.reduce(__high2half(*scratch), &tmp);
half2* pscratch = reinterpret_cast<half2*>(scratch);
half tmp = __float2half(0.f);
typedef packet_traits<Eigen::half>::type packet_type;
for (int i = 0; i < unpacket_traits<packet_type>::size; i += 2) {
reducer.reduce(__low2half(*pscratch), &tmp);
reducer.reduce(__high2half(*pscratch), &tmp);
pscratch++;
}
*output = tmp;
}
@ -345,11 +411,13 @@ template <typename Self, typename Op>
struct FullReductionLauncher<Self, Op, Eigen::half, true> {
static void run(const Self& self, Op& reducer, const GpuDevice& device, half* output, typename Self::Index num_coeffs) {
typedef typename Self::Index Index;
typedef typename packet_traits<Eigen::half>::type PacketType;
const int block_size = 256;
const int num_per_thread = 128;
const int num_blocks = divup<int>(num_coeffs, block_size * num_per_thread);
half2* scratch = static_cast<half2*>(device.scratchpad());
PacketType* scratch = static_cast<PacketType*>(device.scratchpad());
// half2* scratch = static_cast<half2*>(device.scratchpad());
if (num_blocks > 1) {
// We initialize the output and the scrathpad outside the reduction kernel when we can't be sure that there
@ -459,8 +527,8 @@ __global__ void InnerReductionKernel(Reducer reducer, const Self input, Index nu
for (int offset = warpSize/2; offset > 0; offset /= 2) {
#if defined(EIGEN_HIPCC)
// use std::is_floating_point to determine the type of reduced_val
// This is needed because when Type == double, hipcc will give a "call to __shfl_down is ambguous" error
// and list the float and int versions of __shfl_down as the candidate functions.
// This is needed because when Type == double, hipcc will give a "call to __shfl_down is ambguous" error
// and list the float and int versions of __shfl_down as the candidate functions.
if (std::is_floating_point<Type>::value) {
reducer.reduce(__shfl_down(static_cast<float>(reduced_val), offset), &reduced_val);
} else {
@ -494,7 +562,9 @@ __global__ void InnerReductionKernelHalfFloat(Reducer reducer, const Self input,
eigen_assert(gridDim.y == 1);
eigen_assert(gridDim.z == 1);
const int unroll_times = 16;
typedef typename packet_traits<Eigen::half>::type PacketType;
const int packet_width = unpacket_traits<PacketType>::size;
const int unroll_times = 16 / packet_width;
eigen_assert(NumPerThread % unroll_times == 0);
eigen_assert(unroll_times % 2 == 0);
@ -506,10 +576,11 @@ __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 = 2*thread_id;
for (; i + 1 < num_preserved_coeffs; i += 2*num_threads) {
half* loc = output + i;
*((half2*)loc) = reducer.template initializePacket<half2>();
Index i = packet_width * thread_id;
for (; i + packet_width <= num_preserved_coeffs;
i += packet_width * num_threads) {
PacketType* poutput = reinterpret_cast<PacketType*>(output + i);
*poutput = reducer.template initializePacket<PacketType>();
}
if (i < num_preserved_coeffs) {
output[i] = reducer.initialize();
@ -518,42 +589,71 @@ __global__ void InnerReductionKernelHalfFloat(Reducer reducer, const Self input,
}
for (Index i = blockIdx.x; i < num_input_blocks; i += gridDim.x) {
const Index row = 2 * (i / input_col_blocks);
const Index row = 2 * (i / input_col_blocks); // everybody takes 2 rows
if (row + 1 < num_preserved_coeffs) {
const Index col_block = i % input_col_blocks;
const Index col_begin = 2 * (col_block * blockDim.x * NumPerThread + threadIdx.x);
const Index col_begin =
packet_width * (col_block * blockDim.x * NumPerThread + threadIdx.x);
half2 reduced_val1 = reducer.template initializePacket<half2>();
half2 reduced_val2 = reducer.template initializePacket<half2>();
PacketType reduced_val1 = reducer.template initializePacket<PacketType>();
PacketType reduced_val2 = reducer.template initializePacket<PacketType>();
for (Index j = 0; j < NumPerThread; j += unroll_times) {
const Index last_col = col_begin + blockDim.x * (j + unroll_times - 1) * 2;
const Index last_col =
col_begin + blockDim.x * (j + unroll_times - 1) * packet_width;
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 val1 = input.m_impl.template packet<Unaligned>(row * num_coeffs_to_reduce + col);
for (; col + packet_width <= num_coeffs_to_reduce;
col += blockDim.x) {
const PacketType 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);
const PacketType 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 last1 = input.m_impl.coeff(row * num_coeffs_to_reduce + col);
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);
const half2 val2 = __halves2half2(last2, reducer.initialize());
reducer.reducePacket(val2, &reduced_val2);
PacketType r1 = reducer.template initializePacket<PacketType>();
PacketType r2 = reducer.template initializePacket<PacketType>();
half2* hr1 = reinterpret_cast<half2*>(&r1);
half2* hr2 = reinterpret_cast<half2*>(&r2);
while (col + 1 < num_coeffs_to_reduce) {
*hr1 = __halves2half2(
input.m_impl.coeff(row * num_coeffs_to_reduce + col),
input.m_impl.coeff(row * num_coeffs_to_reduce + col + 1));
*hr2 = __halves2half2(
input.m_impl.coeff((row + 1) * num_coeffs_to_reduce + col),
input.m_impl.coeff((row + 1) * num_coeffs_to_reduce + col +
1));
hr1++;
hr2++;
col += 2;
}
if (col < num_coeffs_to_reduce) {
// Peel;
const half last1 =
input.m_impl.coeff(row * num_coeffs_to_reduce + col);
*hr1 = __halves2half2(last1, reducer.initialize());
const half last2 =
input.m_impl.coeff((row + 1) * num_coeffs_to_reduce + col);
*hr2 = __halves2half2(last2, reducer.initialize());
}
reducer.reducePacket(r1, &reduced_val1);
reducer.reducePacket(r2, &reduced_val2);
}
break;
} else {
// Faster version of the loop with no branches after unrolling.
#pragma unroll
for (int k = 0; k < unroll_times; ++k) {
const Index col = col_begin + blockDim.x * (j + k) * 2;
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);
const Index col = col_begin + blockDim.x * (j + k) * packet_width;
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);
}
}
}
@ -561,33 +661,63 @@ __global__ void InnerReductionKernelHalfFloat(Reducer reducer, const Self input,
#pragma unroll
for (int offset = warpSize/2; offset > 0; offset /= 2) {
#if defined(EIGEN_HIPCC)
// FIXME : remove this workaround once we have native half/half2 support for __shfl_down
union { int i; half2 h; } wka_in, wka_out;
// FIXME : remove this workaround once we have native half/half2 support for __shfl_down
union { int i; half2 h; } wka_in, wka_out;
wka_in.h = reduced_val1;
wka_out.i = __shfl_down(wka_in.i, offset, warpSize);
wka_in.h = reduced_val1;
wka_out.i = __shfl_down(wka_in.i, offset, warpSize);
reducer.reducePacket(wka_out.h, &reduced_val1);
wka_in.h = reduced_val2;
wka_out.i = __shfl_down(wka_in.i, offset, warpSize);
wka_in.h = reduced_val2;
wka_out.i = __shfl_down(wka_in.i, offset, warpSize);
reducer.reducePacket(wka_out.h, &reduced_val2);
#elif defined(EIGEN_CUDA_SDK_VER) && EIGEN_CUDA_SDK_VER < 90000
reducer.reducePacket(__shfl_down(reduced_val1, offset, warpSize), &reduced_val1);
reducer.reducePacket(__shfl_down(reduced_val2, offset, warpSize), &reduced_val2);
PacketType r1;
PacketType r2;
half2* hr1 = reinterpret_cast<half2*>(&r1);
half2* hr2 = reinterpret_cast<half2*>(&r2);
half2* rv1 = reinterpret_cast<half2*>(&reduced_val1);
half2* rv2 = reinterpret_cast<half2*>(&reduced_val2);
for (int i = 0; i < packet_width / 2; i++) {
hr1[i] = __shfl_down(rv1[i], offset, warpSize);
hr2[i] = __shfl_down(rv2[i], offset, warpSize);
}
reducer.reducePacket(r1, &reduced_val1);
reducer.reducePacket(r2, &reduced_val2);
#else
int temp1 = __shfl_down_sync(0xFFFFFFFF, *(int*)(&reduced_val1), (unsigned)offset, warpSize);
int temp2 = __shfl_down_sync(0xFFFFFFFF, *(int*)(&reduced_val2), (unsigned)offset, warpSize);
reducer.reducePacket(*(half2*)(&temp1), &reduced_val1);
reducer.reducePacket(*(half2*)(&temp2), &reduced_val2);
PacketType r1;
PacketType r2;
half2* hr1 = reinterpret_cast<half2*>(&r1);
half2* hr2 = reinterpret_cast<half2*>(&r2);
half2* rr1 = reinterpret_cast<half2*>(&reduced_val1);
half2* rr2 = reinterpret_cast<half2*>(&reduced_val2);
for (int i = 0; i < packet_width / 2; i++) {
hr1[i] =
__shfl_down_sync(0xFFFFFFFF, rr1[i], (unsigned)offset, warpSize);
hr2[i] =
__shfl_down_sync(0xFFFFFFFF, rr2[i], (unsigned)offset, warpSize);
}
reducer.reducePacket(r1, &reduced_val1);
reducer.reducePacket(r2, &reduced_val2);
#endif
}
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);
half2* rv1 = reinterpret_cast<half2*>(&reduced_val1);
half2* rv2 = reinterpret_cast<half2*>(&reduced_val2);
half2 val;
if (packet_width > 2) {
reducer.reducePacket(rv1[2], rv1);
reducer.reducePacket(rv1[3], rv1 + 1);
reducer.reducePacket(rv1[1], rv1);
reducer.reducePacket(rv2[2], rv2);
reducer.reducePacket(rv2[3], rv2 + 1);
reducer.reducePacket(rv2[1], rv2);
}
half val1 = __low2half(*rv1);
reducer.reduce(__high2half(*rv1), &val1);
half val2 = __low2half(*rv2);
reducer.reduce(__high2half(*rv2), &val2);
val = __halves2half2(val1, val2);
if ((threadIdx.x & (warpSize - 1)) == 0) {
half* loc = output + row;
atomicReduce((half2*)loc, val, reducer);