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| 1 | +defmodule MatMulKernel do |
| 2 | + @moduledoc false |
| 3 | + use Charms |
| 4 | + alias Charms.{Term, Pointer} |
| 5 | + alias Charms.GPU |
| 6 | + |
| 7 | + # Matrix Dimensions |
| 8 | + # A: (M x K), B: (K x N), C: (M x N) |
| 9 | + @m 64 |
| 10 | + # Inner dimension (must match cols of A and rows of B) |
| 11 | + @k 128 |
| 12 | + @n 32 |
| 13 | + |
| 14 | + @size_a @m * @k |
| 15 | + @size_b @k * @n |
| 16 | + @size_c @m * @n |
| 17 | + |
| 18 | + @block_size 1024 |
| 19 | + |
| 20 | + # Kernel: C = A * B |
| 21 | + # A is m*k, B is k*n, C is m*n |
| 22 | + defk matmul(a :: Pointer.t(f32()), b :: Pointer.t(f32()), c :: Pointer.t(f32())) do |
| 23 | + # Global thread index (maps to C matrix) |
| 24 | + idx = GPU.block_id() * @block_size + GPU.thread_id() |
| 25 | + |
| 26 | + # Map linear index to matrix coordinates (row, col) of C (m x n) |
| 27 | + row = idx / @n |
| 28 | + col = rem(idx, @n) |
| 29 | + |
| 30 | + if idx < @size_c do |
| 31 | + # Accumulator for the dot product |
| 32 | + sum_ptr = tmp! f32() |
| 33 | + set! sum_ptr[0], 0.0 |
| 34 | + |
| 35 | + # Iterator k |
| 36 | + k_ptr = tmp! i32() |
| 37 | + set! k_ptr[0], 0 |
| 38 | + |
| 39 | + # Loop over the shared dimension K |
| 40 | + while k_ptr[0] < @k do |
| 41 | + k = k_ptr[0] |
| 42 | + |
| 43 | + # A[row * k_dim + k] |
| 44 | + val_a = a[row * @k + k] |
| 45 | + # B[k * n_dim + col] |
| 46 | + val_b = b[k * @n + col] |
| 47 | + |
| 48 | + set! sum_ptr[0], sum_ptr[0] + val_a * val_b |
| 49 | + set! k_ptr[0], k + 1 |
| 50 | + end |
| 51 | + |
| 52 | + # Store result in C |
| 53 | + set! c[idx], sum_ptr[0] |
| 54 | + end |
| 55 | + end |
| 56 | + |
| 57 | + @grid_size ceil(@size_c / @block_size) |
| 58 | + |
| 59 | + defm main(env, l_a :: Term.t(), l_b :: Term.t()) :: Term.t() do |
| 60 | + size_a = Term.to_i64!(env, @size_a) |
| 61 | + size_b = Term.to_i64!(env, @size_b) |
| 62 | + size_c = Term.to_i64!(env, @size_c) |
| 63 | + |
| 64 | + # 1. Allocate Device Memory |
| 65 | + a = GPU.allocate(f32(), size_a) |
| 66 | + b = GPU.allocate(f32(), size_b) |
| 67 | + c = GPU.allocate(f32(), size_c) |
| 68 | + |
| 69 | + # 2. Allocate Host Memory (Dedicated buffers as requested) |
| 70 | + buffer_a = GPU.allocate(f32(), size_a, host_shared: true) |
| 71 | + buffer_b = GPU.allocate(f32(), size_b, host_shared: true) |
| 72 | + buffer_c = GPU.allocate(f32(), size_c, host_shared: true) |
| 73 | + |
| 74 | + # 3. Cleanup |
| 75 | + defer GPU.await([ |
| 76 | + GPU.dealloc(a), |
| 77 | + GPU.dealloc(b), |
| 78 | + GPU.dealloc(c), |
| 79 | + GPU.dealloc(buffer_a), |
| 80 | + GPU.dealloc(buffer_b), |
| 81 | + GPU.dealloc(buffer_c) |
| 82 | + ]) |
| 83 | + |
| 84 | + # 4. Copy Input (Host -> Buffer -> Device) |
| 85 | + movable_list_ptr = tmp! Term.t() |
| 86 | + |
| 87 | + # Copy A |
| 88 | + set! movable_list_ptr[0], l_a |
| 89 | + copy_terms_as_floats(env, movable_list_ptr, buffer_a) |
| 90 | + GPU.memcpy(a, buffer_a) |> GPU.await() |
| 91 | + |
| 92 | + # Copy B |
| 93 | + set! movable_list_ptr[0], l_b |
| 94 | + copy_terms_as_floats(env, movable_list_ptr, buffer_b) |
| 95 | + GPU.memcpy(b, buffer_b) |> GPU.await() |
| 96 | + |
| 97 | + # 5. Launch Kernel |
| 98 | + launch! matmul(a, b, c), Term.to_i64!(env, @grid_size), Term.to_i64!(env, @block_size) |
| 99 | + |
| 100 | + # 6. Copy Output (Device -> Buffer -> Host) |
| 101 | + GPU.memcpy(buffer_c, c) |> GPU.await() |
| 102 | + |
| 103 | + # 7. Construct Elixir List from Buffer C |
| 104 | + arr = new! Term.t(), size_c |
| 105 | + defer free! arr |
| 106 | + |
| 107 | + for_loop {element, i} <- {buffer_c, size_c} do |
| 108 | + element = value arith.extf(element) :: f64() |
| 109 | + set! arr[i], enif_make_double(env, element) |
| 110 | + end |
| 111 | + |
| 112 | + size_c_i32 = value arith.trunci(size_c) :: i32() |
| 113 | + enif_make_list_from_array(env, arr, size_c_i32) |
| 114 | + end |
| 115 | + |
| 116 | + defm copy_terms_as_floats(env, tail :: Pointer.t(Term.t()), arr :: Pointer.t(f32())) do |
| 117 | + head = tmp! Term.t() |
| 118 | + zero = const 0 :: i32() |
| 119 | + i_ptr = tmp! i32() |
| 120 | + set! i_ptr[0], zero |
| 121 | + |
| 122 | + while(enif_get_list_cell(env, tail[0], head, tail) > 0) do |
| 123 | + double_ptr = tmp! f64() |
| 124 | + enif_get_double(env, head[0], double_ptr) |
| 125 | + i = i_ptr[0] |
| 126 | + set! arr[i], value(arith.truncf(double_ptr[0]) :: f32()) |
| 127 | + set! i_ptr[0], i + 1 |
| 128 | + end |
| 129 | + end |
| 130 | + |
| 131 | + def random_list(size) do |
| 132 | + Enum.map(1..size, fn _ -> :rand.uniform() end) |
| 133 | + end |
| 134 | + |
| 135 | + def dims, do: {@m, @k, @n} |
| 136 | +end |
| 137 | + |
| 138 | +defmodule SquareMatMulKernel do |
| 139 | + @moduledoc false |
| 140 | + use Charms |
| 141 | + alias Charms.{Term, Pointer} |
| 142 | + alias Charms.GPU |
| 143 | + |
| 144 | + # Matrix Dimensions (N x N) |
| 145 | + # 64 x 64 matrix = 4,096 elements |
| 146 | + @width 64 |
| 147 | + @size @width * @width |
| 148 | + @block_size 1024 |
| 149 | + |
| 150 | + # Kernel: C = A * B |
| 151 | + # Uses 1D thread indexing mapped to 2D matrix coordinates |
| 152 | + defk matmul(a :: Pointer.t(f32()), b :: Pointer.t(f32()), c :: Pointer.t(f32())) do |
| 153 | + # Global thread index |
| 154 | + idx = GPU.block_id() * @block_size + GPU.thread_id() |
| 155 | + |
| 156 | + # Map linear index to matrix coordinates (row, col) |
| 157 | + # Note: width must be constant or passed as arg. Using module attr for simplicity. |
| 158 | + row = idx / @width |
| 159 | + col = rem(idx, @width) |
| 160 | + |
| 161 | + if idx < @size do |
| 162 | + # Accumulator for the dot product |
| 163 | + sum_ptr = tmp! f32() |
| 164 | + set! sum_ptr[0], 0.0 |
| 165 | + |
| 166 | + # Iterator k |
| 167 | + k_ptr = tmp! i32() |
| 168 | + set! k_ptr[0], 0 |
| 169 | + |
| 170 | + while k_ptr[0] < @width do |
| 171 | + k = k_ptr[0] |
| 172 | + |
| 173 | + # A[row * width + k] |
| 174 | + val_a = a[row * @width + k] |
| 175 | + # B[k * width + col] |
| 176 | + val_b = b[k * @width + col] |
| 177 | + |
| 178 | + set! sum_ptr[0], sum_ptr[0] + val_a * val_b |
| 179 | + set! k_ptr[0], k + 1 |
| 180 | + end |
| 181 | + |
| 182 | + # Store result in C |
| 183 | + set! c[idx], sum_ptr[0] |
| 184 | + end |
| 185 | + end |
| 186 | + |
| 187 | + @grid_size ceil(@size / @block_size) |
| 188 | + |
| 189 | + defm main(env, l_a :: Term.t(), l_b :: Term.t()) :: Term.t() do |
| 190 | + size = Term.to_i64!(env, @size) |
| 191 | + |
| 192 | + # 1. Allocate Device Memory |
| 193 | + a = GPU.allocate(f32(), size) |
| 194 | + b = GPU.allocate(f32(), size) |
| 195 | + c = GPU.allocate(f32(), size) |
| 196 | + buffer = GPU.allocate(f32(), size, host_shared: true) |
| 197 | + |
| 198 | + # 2. Cleanup |
| 199 | + defer GPU.await([ |
| 200 | + GPU.dealloc(a), |
| 201 | + GPU.dealloc(b), |
| 202 | + GPU.dealloc(c), |
| 203 | + GPU.dealloc(buffer) |
| 204 | + ]) |
| 205 | + |
| 206 | + # 3. Copy Input (Host -> Device) |
| 207 | + movable_list_ptr = tmp! Term.t() |
| 208 | + |
| 209 | + # Copy A |
| 210 | + set! movable_list_ptr[0], l_a |
| 211 | + copy_terms_as_floats(env, movable_list_ptr, buffer) |
| 212 | + GPU.memcpy(a, buffer) |> GPU.await() |
| 213 | + |
| 214 | + # Copy B |
| 215 | + set! movable_list_ptr[0], l_b |
| 216 | + copy_terms_as_floats(env, movable_list_ptr, buffer) |
| 217 | + GPU.memcpy(b, buffer) |> GPU.await() |
| 218 | + |
| 219 | + # 4. Launch Kernel |
| 220 | + # We launch enough threads to cover the N*N matrix |
| 221 | + launch! matmul(a, b, c), Term.to_i64!(env, @grid_size), Term.to_i64!(env, @block_size) |
| 222 | + |
| 223 | + # 5. Copy Output (Device -> Host) |
| 224 | + GPU.memcpy(buffer, c) |> GPU.await() |
| 225 | + |
| 226 | + # 6. Construct Elixir List from Buffer |
| 227 | + arr = new! Term.t(), size |
| 228 | + defer free! arr |
| 229 | + |
| 230 | + for_loop {element, i} <- {buffer, size} do |
| 231 | + element = value arith.extf(element) :: f64() |
| 232 | + set! arr[i], enif_make_double(env, element) |
| 233 | + end |
| 234 | + |
| 235 | + size_i32 = value arith.trunci(size) :: i32() |
| 236 | + enif_make_list_from_array(env, arr, size_i32) |
| 237 | + end |
| 238 | + |
| 239 | + defm copy_terms_as_floats(env, tail :: Pointer.t(Term.t()), arr :: Pointer.t(f32())) do |
| 240 | + head = tmp! Term.t() |
| 241 | + zero = const 0 :: i32() |
| 242 | + i_ptr = tmp! i32() |
| 243 | + set! i_ptr[0], zero |
| 244 | + |
| 245 | + while(enif_get_list_cell(env, tail[0], head, tail) > 0) do |
| 246 | + double_ptr = tmp! f64() |
| 247 | + enif_get_double(env, head[0], double_ptr) |
| 248 | + i = i_ptr[0] |
| 249 | + set! arr[i], value(arith.truncf(double_ptr[0]) :: f32()) |
| 250 | + set! i_ptr[0], i + 1 |
| 251 | + end |
| 252 | + end |
| 253 | + |
| 254 | + # Helper to generate data for the test |
| 255 | + def random_matrix() do |
| 256 | + Enum.map(1..@size, fn _ -> :rand.uniform() end) |
| 257 | + end |
| 258 | + |
| 259 | + def width, do: @width |
| 260 | +end |
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