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-rw-r--r--unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h8
-rw-r--r--unsupported/Eigen/CXX11/src/Tensor/TensorReductionCuda.h170
2 files changed, 159 insertions, 19 deletions
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h b/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
index 885295f0a..97f4b34b3 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
@@ -322,6 +322,12 @@ struct OuterReducer {
template <int B, int N, typename S, typename R, typename I>
__global__ void FullReductionKernel(R, const S, I, typename S::CoeffReturnType*);
+
+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 InnerReductionKernel(R, const S, I, I, typename S::CoeffReturnType*);
@@ -618,6 +624,8 @@ struct TensorEvaluator<const TensorReductionOp<Op, Dims, ArgType>, Device>
#endif
#if defined(EIGEN_USE_GPU) && defined(__CUDACC__)
template <int B, int N, typename S, typename R, typename I> friend void internal::FullReductionKernel(R, const S, I, typename S::CoeffReturnType*);
+ 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::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
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorReductionCuda.h b/unsupported/Eigen/CXX11/src/Tensor/TensorReductionCuda.h
index fd2587dd5..9186dffe4 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorReductionCuda.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorReductionCuda.h
@@ -67,6 +67,30 @@ __device__ EIGEN_ALWAYS_INLINE void atomicReduce(T* output, T accum, R& reducer)
#endif
}
+
+template <template <typename T> class R>
+__device__ inline void atomicReduce(half2* output, half2 accum, R<half>& reducer) {
+#if __CUDA_ARCH__ >= 300
+ unsigned int oldval = *reinterpret_cast<unsigned int*>(output);
+ unsigned int newval = oldval;
+ reducer.reducePacket(accum, reinterpret_cast<half2*>(&newval));
+ if (newval == oldval) {
+ return;
+ }
+ unsigned int readback;
+ while ((readback = atomicCAS((unsigned int*)output, oldval, newval)) != oldval) {
+ oldval = readback;
+ newval = oldval;
+ reducer.reducePacket(accum, reinterpret_cast<half2*>(&newval));
+ if (newval == oldval) {
+ return;
+ }
+ }
+#else
+ assert(0 && "Shouldn't be called on unsupported device");
+#endif
+}
+
template <typename T>
__device__ inline void atomicReduce(T* output, T accum, SumReducer<T>&) {
#if __CUDA_ARCH__ >= 300
@@ -108,7 +132,7 @@ __global__ void FullReductionKernel(Reducer reducer, const Self input, Index num
#pragma unroll
for (int offset = warpSize/2; offset > 0; offset /= 2) {
- reducer.reduce(__shfl_down(accum, offset), &accum);
+ reducer.reduce(__shfl_down(accum, offset, warpSize), &accum);
}
if ((threadIdx.x & (warpSize - 1)) == 0) {
@@ -117,28 +141,78 @@ __global__ void FullReductionKernel(Reducer reducer, const Self input, Index num
}
-template <typename Self, typename Op, bool Vectorizable>
-struct FullReducer<Self, Op, GpuDevice, Vectorizable> {
- // 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 OutputType>
- static EIGEN_DEVICE_FUNC void run(const Self&, Op&, const GpuDevice&, OutputType*) {
- assert(false && "Should only be called on floats");
+#ifdef EIGEN_HAS_CUDA_FP16
+template <typename Self,
+ typename Reducer, typename Index>
+__global__ void ReductionInitKernelHalfFloat(Reducer reducer, const Self input, Index num_coeffs, half2* scratch) {
+ eigen_assert(threadIdx.x == 1);
+ if (num_coeffs % 2 != 0) {
+ half last = input.m_impl.coeff(num_coeffs-1);
+ *scratch = __halves2half2(last, reducer.initialize());
+ } else {
+ *scratch = reducer.template initializePacket<half2>();
}
+}
- static void run(const Self& self, Op& reducer, const GpuDevice& device, float* output) {
- typedef typename Self::Index Index;
+template <int BlockSize, int NumPerThread, typename Self,
+ typename Reducer, typename Index>
+static __global__ void FullReductionKernelHalfFloat(Reducer reducer, const Self input, Index num_coeffs,
+ half* output, half2* scratch) {
+ eigen_assert(NumPerThread % 2 == 0);
- 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;
+ const Index first_index = blockIdx.x * BlockSize * NumPerThread + 2*threadIdx.x;
+
+ // Initialize the output value if it wasn't initialized by the ReductionInitKernel
+ if (gridDim.x == 1 && first_index == 0) {
+ if (num_coeffs % 2 != 0) {
+ half last = input.m_impl.coeff(num_coeffs-1);
+ *scratch = __halves2half2(last, reducer.initialize());
+ } else {
+ *scratch = reducer.template initializePacket<half2>();
}
+ }
+
+ half2 accum = reducer.template initializePacket<half2>();
+ Index max_iter = numext::mini<Index>((num_coeffs - first_index) / 2, NumPerThread*BlockSize / 2);
+ 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);
+ reducer.reducePacket(val, &accum);
+ }
+
+#pragma unroll
+ for (int offset = warpSize/2; offset > 0; offset /= 2) {
+ reducer.reducePacket(__shfl_down(accum, offset, warpSize), &accum);
+ }
+
+ if ((threadIdx.x & (warpSize - 1)) == 0) {
+ atomicReduce(scratch, accum, reducer);
+ }
+
+ __syncthreads();
+
+ if (gridDim.x == 1 && first_index == 0) {
+ reducer.reduce(__low2half(*scratch), output);
+ reducer.reduce(__high2half(*scratch), output);
+ }
+}
+
+template <typename Op>
+__global__ void ReductionCleanupKernelHalfFloat(Op& reducer, half* output, half2* scratch) {
+ eigen_assert(threadIdx.x == 1);
+ reducer.reduce(__low2half(*scratch), output);
+ reducer.reduce(__high2half(*scratch), output);
+}
+
+#endif
+
+template <typename Self, typename Op, bool is_half>
+struct Launcher {
+ static void run(const Self& self, Op& reducer, const GpuDevice& device, typename Self::CoeffReturnType* output, typename Self::Index num_coeffs) {
+ typedef typename Self::Index Index;
+ typedef typename Self::CoeffReturnType Scalar;
const int block_size = 256;
const int num_per_thread = 128;
const int num_blocks = divup<int>(num_coeffs, block_size * num_per_thread);
@@ -155,6 +229,64 @@ struct FullReducer<Self, Op, GpuDevice, Vectorizable> {
}
};
+#ifdef EIGEN_HAS_CUDA_FP16
+template <typename Self, typename Op>
+struct Launcher<Self, Op, true> {
+ static void run(const Self& self, Op& reducer, const GpuDevice& device, half* output, typename Self::Index num_coeffs) {
+ typedef typename Self::Index Index;
+
+ 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());
+
+ if (num_blocks > 1) {
+ // We initialize the output and the scrathpad outside the reduction kernel when we can't be sure that there
+ // won't be a race conditions between multiple thread blocks.
+ LAUNCH_CUDA_KERNEL((ReductionInitKernelHalfFloat<Self, Op, Index>),
+ 1, 1, 0, device, reducer, self, num_coeffs, scratch);
+ }
+
+ LAUNCH_CUDA_KERNEL((FullReductionKernelHalfFloat<block_size, num_per_thread, Self, Op, Index>),
+ num_blocks, block_size, 0, device, reducer, self, num_coeffs, output, scratch);
+
+ if (num_blocks > 1) {
+ LAUNCH_CUDA_KERNEL((ReductionCleanupKernelHalfFloat<Op>),
+ 1, 1, 0, device, reducer, output, scratch);
+ }
+ }
+};
+#endif
+
+
+template <typename Self, typename Op, bool Vectorizable>
+struct FullReducer<Self, Op, GpuDevice, Vectorizable> {
+ // 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 void run(const Self& self, Op& reducer, const GpuDevice& device, OutputType* output) {
+ 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;
+ }
+
+ static const bool is_half = internal::is_same<typename Self::CoeffReturnType, half>::value;
+ Launcher<Self, Op, is_half>::run(self, reducer, device, output, num_coeffs);
+ }
+};
+
template <int NumPerThread, typename Self,
typename Reducer, typename Index>
@@ -323,7 +455,7 @@ struct OuterReducer<Self, Op, GpuDevice> {
return true;
}
- const Index num_coeffs = num_coeffs_to_reduce * num_preserved_vals;
+ const Index num_coeffs = num_coeffs_to_reduce * num_preserved_vals;
const int block_size = 256;
const int num_per_thread = 16;
const int dyn_blocks = divup<int>(num_coeffs, block_size * num_per_thread);