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#pragma once
#include "vectorization.cuh"
namespace vllm {
template <int VEC_SIZE, typename InT, typename OutT, typename ScaOp>
struct DefaultVecOp {
ScaOp scalar_op;
__device__ __forceinline__ void operator()(
vec_n_t<OutT, VEC_SIZE>& dst, const vec_n_t<InT, VEC_SIZE>& src) const {
#pragma unroll
for (int i = 0; i < VEC_SIZE; ++i) {
scalar_op(dst.val[i], src.val[i]);
}
}
};
template <int VEC_SIZE, typename InT, typename OutT, typename VecOp,
typename ScaOp>
__device__ inline void vectorize_with_alignment(
const InT* in, OutT* out, int len, int tid, int stride,
VecOp&& vec_op, // vec_n_t<InT,16> -> vec_n_t<OutT,16>
ScaOp&& scalar_op) { // InT -> OutT
static_assert(VEC_SIZE > 0 && (VEC_SIZE & (VEC_SIZE - 1)) == 0,
"VEC_SIZE must be a positive power-of-two");
constexpr int WIDTH = VEC_SIZE * sizeof(InT); // eg: 64 B
uintptr_t addr = reinterpret_cast<uintptr_t>(in);
int misalignment_offset = addr & (WIDTH - 1); // addr % 64
int alignment_bytes = WIDTH - misalignment_offset; // 64 - (addr % 64)
int prefix_elems = alignment_bytes & (WIDTH - 1); // handle 64
prefix_elems /= sizeof(InT);
prefix_elems = min(prefix_elems, len); // 0 ≤ prefix < 16
// 1. prefill the when it is unsafe to vectorize
for (int i = tid; i < prefix_elems; i += stride) {
scalar_op(out[i], in[i]);
}
in += prefix_elems;
out += prefix_elems;
len -= prefix_elems;
int num_vec = len / VEC_SIZE;
using vin_t = vec_n_t<InT, VEC_SIZE>;
using vout_t = vec_n_t<OutT, VEC_SIZE>;
auto* v_in = reinterpret_cast<const vin_t*>(in);
auto* v_out = reinterpret_cast<vout_t*>(out);
// 2. vectorize the main part
for (int i = tid; i < num_vec; i += stride) {
vout_t tmp;
vec_op(tmp, v_in[i]);
v_out[i] = tmp;
}
// 3. handle the tail
int tail_start = num_vec * VEC_SIZE;
for (int i = tid + tail_start; i < len; i += stride) {
scalar_op(out[i], in[i]);
}
}
template <int VEC_SIZE, typename InT, typename OutT, typename ScaOp>
__device__ __forceinline__ void vectorize_with_alignment(const InT* in,
OutT* out, int len,
int tid, int stride,
ScaOp&& scalar_op) {
using Vec = DefaultVecOp<VEC_SIZE, InT, OutT, std::decay_t<ScaOp>>;
vectorize_with_alignment<VEC_SIZE>(in, out, len, tid, stride, Vec{scalar_op},
std::forward<ScaOp>(scalar_op));
}
} // namespace vllm
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