mlx/mlx/backend/metal/quantized.cpp
2024-04-24 13:07:45 -07:00

200 lines
6.6 KiB
C++

// Copyright © 2023-2024 Apple Inc.
#include <cassert>
#include "mlx/backend/metal/copy.h"
#include "mlx/backend/metal/device.h"
#include "mlx/backend/metal/utils.h"
#include "mlx/primitives.h"
namespace mlx::core {
void QuantizedMatmul::eval_gpu(const std::vector<array>& inputs, array& out) {
assert(inputs.size() == 4);
out.set_data(allocator::malloc_or_wait(out.nbytes()));
auto& s = stream();
auto& d = metal::device(s.device);
auto& x_pre = inputs[0];
auto& w_pre = inputs[1];
auto& scales_pre = inputs[2];
auto& biases_pre = inputs[3];
std::vector<array> copies;
auto ensure_row_contiguous = [&copies, &s](const array& arr) {
if (arr.flags().row_contiguous) {
return arr;
} else {
array arr_copy(arr.shape(), arr.dtype(), nullptr, {});
copy_gpu(arr, arr_copy, CopyType::General, s);
copies.push_back(arr_copy);
return arr_copy;
}
};
auto x = ensure_row_contiguous(x_pre);
auto w = ensure_row_contiguous(w_pre);
auto scales = ensure_row_contiguous(scales_pre);
auto biases = ensure_row_contiguous(biases_pre);
int D = x.shape(-1);
int B = x.size() / D;
int O = out.shape(-1);
if (transpose_) {
// Route to the fast qmv kernel that has no bounds checking
if (B < 6 && O % 8 == 0 && D % 512 == 0 && D >= 512) {
std::ostringstream kname;
kname << "qmv_" << type_to_name(out) << "_gs_" << group_size_ << "_b_"
<< bits_ << "_fast";
// Encode and dispatch kernel
auto& compute_encoder = d.get_command_encoder(s.index);
auto kernel = d.get_kernel(kname.str());
compute_encoder->setComputePipelineState(kernel);
int bo = 8;
int bd = 32;
MTL::Size group_dims = MTL::Size(bd, 2, 1);
MTL::Size grid_dims = MTL::Size(1, O / bo, B);
compute_encoder.set_input_array(w, 0);
compute_encoder.set_input_array(scales, 1);
compute_encoder.set_input_array(biases, 2);
compute_encoder.set_input_array(x, 3);
compute_encoder.set_output_array(out, 4);
compute_encoder->setBytes(&D, sizeof(int), 5);
compute_encoder->setBytes(&O, sizeof(int), 6);
compute_encoder->dispatchThreadgroups(grid_dims, group_dims);
}
// Route to the qmv kernel
else if (B < 6) {
std::ostringstream kname;
kname << "qmv_" << type_to_name(out) << "_gs_" << group_size_ << "_b_"
<< bits_;
// Encode and dispatch kernel
auto& compute_encoder = d.get_command_encoder(s.index);
auto kernel = d.get_kernel(kname.str());
compute_encoder->setComputePipelineState(kernel);
int bo = 8;
int bd = 32;
MTL::Size group_dims = MTL::Size(bd, 2, 1);
MTL::Size grid_dims = MTL::Size(1, (O + bo - 1) / bo, B);
compute_encoder.set_input_array(w, 0);
compute_encoder.set_input_array(scales, 1);
compute_encoder.set_input_array(biases, 2);
compute_encoder.set_input_array(x, 3);
compute_encoder.set_output_array(out, 4);
compute_encoder->setBytes(&D, sizeof(int), 5);
compute_encoder->setBytes(&O, sizeof(int), 6);
compute_encoder->dispatchThreadgroups(grid_dims, group_dims);
}
// Route to the qmm_t kernel
else {
std::ostringstream kname;
kname << "qmm_t_" << type_to_name(out) << "_gs_" << group_size_ << "_b_"
<< bits_ << "_alN_" << std::boolalpha << ((O % 32) == 0);
// Encode and dispatch kernel
auto& compute_encoder = d.get_command_encoder(s.index);
auto kernel = d.get_kernel(kname.str());
compute_encoder->setComputePipelineState(kernel);
int wn = 2;
int wm = 2;
int bm = 32;
int bn = 32;
int bk = 32;
MTL::Size group_dims = MTL::Size(32, wn, wm);
MTL::Size grid_dims = MTL::Size((O + bn - 1) / bn, (B + bm - 1) / bm, 1);
compute_encoder.set_input_array(x, 0);
compute_encoder.set_input_array(w, 1);
compute_encoder.set_input_array(scales, 2);
compute_encoder.set_input_array(biases, 3);
compute_encoder.set_output_array(out, 4);
compute_encoder->setBytes(&B, sizeof(int), 5);
compute_encoder->setBytes(&O, sizeof(int), 6);
compute_encoder->setBytes(&D, sizeof(int), 7);
compute_encoder->dispatchThreadgroups(grid_dims, group_dims);
}
} else {
// Route to the qvm kernel
if (B < 4) {
std::ostringstream kname;
kname << "qvm_" << type_to_name(out) << "_gs_" << group_size_ << "_b_"
<< bits_;
// Encode and dispatch kernel
auto& compute_encoder = d.get_command_encoder(s.index);
auto kernel = d.get_kernel(kname.str());
compute_encoder->setComputePipelineState(kernel);
int bo = 8;
int bd = 32;
MTL::Size group_dims = MTL::Size(bd, bo, 1);
MTL::Size grid_dims = MTL::Size(1, (O + bo - 1) / bo, B);
compute_encoder.set_input_array(x, 0);
compute_encoder.set_input_array(w, 1);
compute_encoder.set_input_array(scales, 2);
compute_encoder.set_input_array(biases, 3);
compute_encoder.set_output_array(out, 4);
compute_encoder->setBytes(&D, sizeof(int), 5);
compute_encoder->setBytes(&O, sizeof(int), 6);
compute_encoder->dispatchThreadgroups(grid_dims, group_dims);
}
// Route to the qmm_n kernel
else {
std::ostringstream kname;
kname << "qmm_n_" << type_to_name(out) << "_gs_" << group_size_ << "_b_"
<< bits_;
// Encode and dispatch kernel
auto& compute_encoder = d.get_command_encoder(s.index);
auto kernel = d.get_kernel(kname.str());
compute_encoder->setComputePipelineState(kernel);
int wn = 2;
int wm = 2;
int bm = 32;
int bn = 32;
int bk = 32;
MTL::Size group_dims = MTL::Size(32, wn, wm);
MTL::Size grid_dims = MTL::Size(O / bn, (B + bm - 1) / bm, 1);
if ((O % bn) != 0) {
std::ostringstream msg;
msg << "[quantized_matmul] The output size should be divisible by "
<< bn << " but received " << O << ".";
throw std::runtime_error(msg.str());
}
compute_encoder.set_input_array(x, 0);
compute_encoder.set_input_array(w, 1);
compute_encoder.set_input_array(scales, 2);
compute_encoder.set_input_array(biases, 3);
compute_encoder.set_output_array(out, 4);
compute_encoder->setBytes(&B, sizeof(int), 5);
compute_encoder->setBytes(&O, sizeof(int), 6);
compute_encoder->setBytes(&D, sizeof(int), 7);
compute_encoder->dispatchThreadgroups(grid_dims, group_dims);
}
}
d.get_command_buffer(s.index)->addCompletedHandler(
[copies](MTL::CommandBuffer*) mutable { copies.clear(); });
}
} // namespace mlx::core