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WarpShuffles.cuh
/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD+Patents license found in the
* LICENSE file in the root directory of this source tree.
*/
// Copyright 2004-present Facebook. All Rights Reserved.
#pragma once
#include <cuda.h>
#include "DeviceDefs.cuh"
#include "Float16.cuh"
namespace faiss { namespace gpu {
template <typename T>
inline __device__ T shfl(const T val,
int srcLane, int width = kWarpSize) {
#if CUDA_VERSION >= 9000
return __shfl_sync(0xffffffff, val, srcLane, width);
#else
return __shfl(val, srcLane, width);
#endif
}
// CUDA SDK does not provide specializations for T*
template <typename T>
inline __device__ T* shfl(T* const val,
int srcLane, int width = kWarpSize) {
static_assert(sizeof(T*) == sizeof(long long), "pointer size");
long long v = (long long) val;
return (T*) shfl(v, srcLane, width);
}
template <typename T>
inline __device__ T shfl_up(const T val,
unsigned int delta, int width = kWarpSize) {
#if CUDA_VERSION >= 9000
return __shfl_up_sync(0xffffffff, val, delta, width);
#else
return __shfl_up(val, delta, width);
#endif
}
// CUDA SDK does not provide specializations for T*
template <typename T>
inline __device__ T* shfl_up(T* const val,
unsigned int delta, int width = kWarpSize) {
static_assert(sizeof(T*) == sizeof(long long), "pointer size");
long long v = (long long) val;
return (T*) shfl_up(v, delta, width);
}
template <typename T>
inline __device__ T shfl_down(const T val,
unsigned int delta, int width = kWarpSize) {
#if CUDA_VERSION >= 9000
return __shfl_down_sync(0xffffffff, val, delta, width);
#else
return __shfl_down(val, delta, width);
#endif
}
// CUDA SDK does not provide specializations for T*
template <typename T>
inline __device__ T* shfl_down(T* const val,
unsigned int delta, int width = kWarpSize) {
static_assert(sizeof(T*) == sizeof(long long), "pointer size");
long long v = (long long) val;
return (T*) shfl_down(v, delta, width);
}
template <typename T>
inline __device__ T shfl_xor(const T val,
int laneMask, int width = kWarpSize) {
#if CUDA_VERSION >= 9000
return __shfl_xor_sync(0xffffffff, val, laneMask, width);
#else
return __shfl_xor(val, laneMask, width);
#endif
}
// CUDA SDK does not provide specializations for T*
template <typename T>
inline __device__ T* shfl_xor(T* const val,
int laneMask, int width = kWarpSize) {
static_assert(sizeof(T*) == sizeof(long long), "pointer size");
long long v = (long long) val;
return (T*) shfl_xor(v, laneMask, width);
}
#ifdef FAISS_USE_FLOAT16
// CUDA 9.0 has half shuffle
#if CUDA_VERSION < 9000
inline __device__ half shfl(half v,
int srcLane, int width = kWarpSize) {
unsigned int vu = v.x;
vu = __shfl(vu, srcLane, width);
half h;
h.x = (unsigned short) vu;
return h;
}
inline __device__ half shfl_xor(half v,
int laneMask, int width = kWarpSize) {
unsigned int vu = v.x;
vu = __shfl_xor(vu, laneMask, width);
half h;
h.x = (unsigned short) vu;
return h;
}
#endif // CUDA_VERSION
#endif // FAISS_USE_FLOAT16
} } // namespace