mlx/mlx/backend/metal/kernels/scatter.h
Awni Hannun 98b6ce3460
Refactor reductions and fix scatter atomics for large sizes (#1300)
Co-authored-by: Angelos Katharopoulos <a_katharopoulos@apple.com>
2024-08-22 16:03:31 -07:00

77 lines
2.5 KiB
C++

// Copyright © 2024 Apple Inc.
#pragma once
#include "mlx/backend/metal/kernels/indexing.h"
template <typename T, typename IdxT, typename Op, int NIDX>
METAL_FUNC void scatter_1d_index_impl(
const device T* updates [[buffer(1)]],
device mlx_atomic<T>* out [[buffer(2)]],
const constant int* out_shape [[buffer(3)]],
const constant size_t* out_strides [[buffer(4)]],
const constant size_t& out_ndim [[buffer(5)]],
const constant int* upd_shape [[buffer(6)]],
const constant size_t& upd_ndim [[buffer(7)]],
const constant size_t& upd_size [[buffer(8)]],
const thread array<const device IdxT*, NIDX>& idx_buffers,
uint2 gid [[thread_position_in_grid]]) {
Op op;
size_t out_idx = 0;
for (int i = 0; i < NIDX; i++) {
auto idx_val = offset_neg_idx(idx_buffers[i][gid.y], out_shape[i]);
out_idx += idx_val * out_strides[i];
}
if (upd_ndim > 1) {
auto out_offset = elem_to_loc(gid.x, upd_shape + 1, out_strides, out_ndim);
out_idx += out_offset;
} else {
out_idx += gid.x;
}
op.atomic_update(out, updates[gid.y * upd_size + gid.x], out_idx);
}
template <typename T, typename IdxT, typename Op, int NIDX>
METAL_FUNC void scatter_impl(
const device T* updates [[buffer(1)]],
device mlx_atomic<T>* out [[buffer(2)]],
const constant int* upd_shape [[buffer(3)]],
const constant size_t* upd_strides [[buffer(4)]],
const constant size_t& upd_ndim [[buffer(5)]],
const constant size_t& upd_size [[buffer(6)]],
const constant int* out_shape [[buffer(7)]],
const constant size_t* out_strides [[buffer(8)]],
const constant size_t& out_ndim [[buffer(9)]],
const constant int* axes [[buffer(10)]],
const thread Indices<IdxT, NIDX>& indices,
uint2 gid [[thread_position_in_grid]]) {
Op op;
auto ind_idx = gid.y;
auto ind_offset = gid.x;
size_t out_idx = 0;
for (int i = 0; i < NIDX; ++i) {
auto idx_loc = elem_to_loc(
ind_idx,
&indices.shapes[indices.ndim * i],
&indices.strides[indices.ndim * i],
indices.ndim);
auto ax = axes[i];
auto idx_val = offset_neg_idx(indices.buffers[i][idx_loc], out_shape[ax]);
out_idx += idx_val * out_strides[ax];
}
if (upd_size > 1) {
auto out_offset = elem_to_loc(
ind_offset, upd_shape + indices.ndim, out_strides, out_ndim);
out_idx += out_offset;
}
auto upd_idx =
elem_to_loc(gid.y * upd_size + gid.x, upd_shape, upd_strides, upd_ndim);
op.atomic_update(out, updates[upd_idx], out_idx);
}