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deepspeedai--deepspeed/csrc/quantization/pt_binding.cpp
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2026-07-13 13:18:33 +08:00

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// Copyright (c) Microsoft Corporation.
// SPDX-License-Identifier: Apache-2.0
// DeepSpeed Team
#include <ATen/cuda/CUDAContext.h>
#include <torch/extension.h>
#include <cassert>
#include <vector>
#include "quantization.h"
template <typename T>
at::Tensor ds_quantize(at::Tensor& vals, int groups, int bits)
{
auto t_size = vals.sizes();
int size = 1;
for (auto dim : t_size) size *= dim;
if ((((size / groups) - 1) / 4096 + 1) <= 256) {
launch_fake_quantize_kernel(
(T*)vals.data_ptr(), size, groups, bits, at::cuda::getCurrentCUDAStream());
}
return vals;
}
template <typename T>
at::Tensor ds_sr_quantize(at::Tensor& vals, int groups, int bits)
{
auto t_size = vals.sizes();
int size = 1;
for (auto dim : t_size) size *= dim;
if (((size / groups) / 4 / 1024) <= 256) {
launch_sr_fake_quantize_kernel(
(T*)vals.data_ptr(), size, groups, bits, at::cuda::getCurrentCUDAStream());
}
return vals;
}
template <typename T>
at::Tensor ds_quantize_asym(at::Tensor& vals, int groups, int bits)
{
auto t_size = vals.sizes();
int size = 1;
for (auto dim : t_size) size *= dim;
if ((((size / groups) - 1) / 4096 + 1) <= 256) {
launch_fake_quantize_kernel_asym(
(T*)vals.data_ptr(), size, groups, bits, at::cuda::getCurrentCUDAStream());
}
return vals;
}
template <typename T>
at::Tensor ds_sr_quantize_asym(at::Tensor& vals, int groups, int bits)
{
auto t_size = vals.sizes();
int size = 1;
for (auto dim : t_size) size *= dim;
if (((size / groups) / 4 / 1024) <= 256) {
launch_sr_fake_quantize_kernel_asym(
(T*)vals.data_ptr(), size, groups, bits, at::cuda::getCurrentCUDAStream());
}
return vals;
}
std::vector<at::Tensor> quantize_kernel(at::Tensor& input_vals,
int groups,
int numBits,
quantize::Type quantType)
{
auto dtype = at::kFloat;
auto params_options = at::TensorOptions()
.dtype(dtype)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
const int param_elems = (quantize::requires_offset(quantType)) ? 2 : 1;
auto params = torch::empty({groups, param_elems}, params_options);
auto output_options = at::TensorOptions()
.dtype(at::kChar)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
auto output_sizes = input_vals.sizes().vec();
output_sizes[output_sizes.size() - 1] /= numBits == 8 ? 1 : 2;
auto output = torch::empty(output_sizes, output_options);
const int elems_per_group = at::numel(input_vals) / groups;
launch_quant((int8_t*)output.data_ptr(),
(float*)params.data_ptr(),
(__half*)input_vals.data_ptr(),
groups,
elems_per_group,
numBits,
quantType,
at::cuda::getCurrentCUDAStream());
return {output, params};
}
template <typename T>
at::Tensor dequantize(at::Tensor& quantized_data,
at::Tensor& params,
int groups,
int num_bits,
quantize::Type quant_type)
{
auto dtype = (std::is_same<T, float>::value) ? torch::kFloat32 : torch::kFloat16;
auto output_options = at::TensorOptions()
.dtype(dtype)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
auto output_sizes = quantized_data.sizes().vec();
output_sizes[output_sizes.size() - 1] *= num_bits == 8 ? 1 : 2;
auto output = torch::empty(output_sizes, output_options);
const int total_elems = at::numel(output);
const int elems_per_group = total_elems / groups;
launch_dequantize_kernel((T*)output.data_ptr(),
(const int8_t*)quantized_data.data_ptr(),
(const float*)params.data_ptr(),
quant_type,
num_bits,
elems_per_group,
total_elems,
at::cuda::getCurrentCUDAStream());
return output;
}
at::Tensor dequantize_int4_to_half_experimental(at::Tensor& data_in,
at::Tensor& scale_buffer,
at::Tensor& min_val_buffer,
int num_group,
int group_size)
{
auto output_options = at::TensorOptions().dtype(at::kHalf).device(at::kCUDA);
auto output = torch::empty({num_group, group_size}, output_options);
launch_dequantize_int4_to_half_experimental((uint8_t*)data_in.data_ptr(),
(half*)output.data_ptr(),
(half*)scale_buffer.data_ptr(),
(half*)min_val_buffer.data_ptr(),
num_group,
group_size,
at::cuda::getCurrentCUDAStream());
return output;
}
at::Tensor dequantize_int8_to_half_experimental(at::Tensor& data_in,
at::Tensor& scale_buffer,
at::Tensor& min_val_buffer,
int num_group,
int group_size)
{
auto output_options = at::TensorOptions().dtype(at::kHalf).device(at::kCUDA);
auto output = torch::empty({num_group, group_size}, output_options);
launch_dequantize_int8_to_half_experimental((uint8_t*)data_in.data_ptr(),
(half*)output.data_ptr(),
(half*)scale_buffer.data_ptr(),
(half*)min_val_buffer.data_ptr(),
num_group,
group_size,
at::cuda::getCurrentCUDAStream());
return output;
}
std::vector<at::Tensor> ds_loco_swizzle_quant(at::Tensor& input_vals,
at::Tensor& error_feedback,
float err_beta,
int groups,
int num_bits,
quantize::Type quant_type,
int pipeline_size,
int nodes,
int devices_per_node)
{
auto scales_options = at::TensorOptions()
.dtype(at::kFloat)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
const int scales_elems = (quantize::requires_offset(quant_type)) ? 2 : 1;
auto scales = torch::empty({groups, scales_elems}, scales_options);
auto output_options = at::TensorOptions()
.dtype(at::kChar)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
const int quantization_scalar = 8 / num_bits;
const int compressed_vals = at::numel(input_vals) / quantization_scalar;
auto output = torch::empty({compressed_vals}, output_options);
const int elems_per_group = at::numel(input_vals) / groups;
launch_loco_swizzled_quant(reinterpret_cast<int8_t*>(output.data_ptr()),
reinterpret_cast<float*>(scales.data_ptr()),
reinterpret_cast<const __half*>(input_vals.data_ptr()),
reinterpret_cast<__half*>(error_feedback.data_ptr()),
err_beta,
num_bits,
quant_type,
groups,
elems_per_group,
pipeline_size,
nodes,
devices_per_node,
at::cuda::getCurrentCUDAStream());
return {output, scales};
}
std::vector<at::Tensor> ds_swizzle_quant(at::Tensor& input_vals,
int groups,
int num_bits,
quantize::Type quant_type,
int pipeline_size,
int nodes,
int devices_per_node)
{
auto scales_options = at::TensorOptions()
.dtype(at::kFloat)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
const int scales_elems = (quantize::requires_offset(quant_type)) ? 2 : 1;
auto scales = torch::empty({groups, scales_elems}, scales_options);
auto output_options = at::TensorOptions()
.dtype(at::kChar)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
const int quantization_scalar = 8 / num_bits;
const int compressed_vals = at::numel(input_vals) / quantization_scalar;
auto output = torch::empty({compressed_vals}, output_options);
const int elems_per_group = at::numel(input_vals) / groups;
launch_swizzled_quant((int8_t*)output.data_ptr(),
(float*)scales.data_ptr(),
(__half*)input_vals.data_ptr(),
num_bits,
quant_type,
groups,
elems_per_group,
pipeline_size,
nodes,
devices_per_node,
at::cuda::getCurrentCUDAStream());
return {output, scales};
}
std::vector<at::Tensor> quantized_reduction(at::Tensor& input_vals,
at::Tensor& input_scales,
int in_groups,
int out_groups,
int num_bits,
quantize::Type quant_type,
int devices_per_node)
{
auto scales_options = at::TensorOptions()
.dtype(at::kFloat)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
const int scales_elems = (quantize::requires_offset(quant_type)) ? 2 : 1;
auto scales = torch::empty({out_groups, scales_elems}, scales_options);
auto output_options = at::TensorOptions()
.dtype(at::kChar)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
std::vector<int64_t> sz(input_vals.sizes().begin(), input_vals.sizes().end());
sz[sz.size() - 1] = sz.back() / devices_per_node; // num of GPU per nodes
const int elems_per_in_tensor = at::numel(input_vals) / devices_per_node;
auto output = torch::empty(sz, output_options);
const int elems_per_in_group = elems_per_in_tensor / (in_groups / devices_per_node);
const int elems_per_out_group = elems_per_in_tensor / out_groups;
launch_dequant_reduce((int8_t*)output.data_ptr(),
(float*)scales.data_ptr(),
(const int8_t*)input_vals.data_ptr(),
(const float*)input_scales.data_ptr(),
devices_per_node,
num_bits,
quant_type,
out_groups,
elems_per_out_group,
elems_per_in_tensor,
in_groups / devices_per_node,
elems_per_in_group,
at::cuda::getCurrentCUDAStream());
return {output, scales};
}
std::vector<at::Tensor> loco_quantized_reduction(at::Tensor& input_vals,
at::Tensor& input_scales,
at::Tensor& error_feedback,
float err_beta,
int in_groups,
int out_groups,
int num_bits,
quantize::Type quant_type,
int devices_per_node)
{
auto scales_options = at::TensorOptions()
.dtype(at::kFloat)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
const int scales_elems = (quantize::requires_offset(quant_type)) ? 2 : 1;
auto scales = torch::empty({out_groups, scales_elems}, scales_options);
auto output_options = at::TensorOptions()
.dtype(at::kChar)
.layout(at::kStrided)
.device(at::kCUDA)
.requires_grad(false);
std::vector<int64_t> sz(input_vals.sizes().begin(), input_vals.sizes().end());
sz[sz.size() - 1] = sz.back() / devices_per_node;
const int elems_per_in_tensor = at::numel(input_vals) / devices_per_node;
auto output = torch::empty(sz, output_options);
const int elems_per_in_group = elems_per_in_tensor / (in_groups / devices_per_node);
const int elems_per_out_group = elems_per_in_tensor / out_groups;
launch_loco_dequant_reduce((int8_t*)output.data_ptr(),
(float*)scales.data_ptr(),
(const int8_t*)input_vals.data_ptr(),
(const float*)input_scales.data_ptr(),
devices_per_node,
num_bits,
quant_type,
out_groups,
elems_per_out_group,
elems_per_in_tensor,
in_groups / devices_per_node,
elems_per_in_group,
(__half2*)error_feedback.data_ptr(),
err_beta,
at::cuda::getCurrentCUDAStream());
return {output, scales};
}
PYBIND11_MODULE(TORCH_EXTENSION_NAME, m)
{
m.def("ds_quantize_fp32", &ds_quantize<float>, "DeepSpeed Quantize with fp32 (CUDA)");
m.def("ds_quantize_fp16", &ds_quantize<__half>, "DeepSpeed Quantize with fp16 (CUDA)");
m.def("ds_sr_quantize_fp32", &ds_sr_quantize<float>, "DeepSpeed Quantize with fp32 (CUDA)");
m.def("ds_sr_quantize_fp16", &ds_sr_quantize<__half>, "DeepSpeed Quantize with fp16 (CUDA)");
m.def("ds_quantize_asym_fp32", &ds_quantize_asym<float>, "DeepSpeed Quantize with fp32 (CUDA)");
m.def(
"ds_quantize_asym_fp16", &ds_quantize_asym<__half>, "DeepSpeed Quantize with fp16 (CUDA)");
m.def("ds_sr_quantize_asym_fp32",
&ds_sr_quantize_asym<float>,
"DeepSpeed Quantize with fp32 (CUDA)");
m.def("ds_sr_quantize_asym_fp16",
&ds_sr_quantize_asym<__half>,
"DeepSpeed Quantize with fp16 (CUDA)");
pybind11::enum_<quantize::Type>(m, "QuantizationType")
.value("Symmetric", quantize::Type::Symmetric)
.value("Asymmetric", quantize::Type::Asymmetric)
.export_values();
m.def("quantize", &quantize_kernel);
m.def("dequantize", &dequantize<__half>);
m.def("dequantize_fp32", &dequantize<float>);
m.def("dequantize_int4_to_half_experimental",
&dequantize_int4_to_half_experimental,
"Dequantize int4 to half (experimental)");
m.def("dequantize_int8_to_half_experimental",
&dequantize_int8_to_half_experimental,
"Dequantize int8 to half (experimental)");
m.def("swizzle_quant", &ds_swizzle_quant);
m.def("quantized_reduction", &quantized_reduction);
m.def("loco_swizzle_quant", &ds_loco_swizzle_quant, "LoCo Swizzled Quantization Kernel");
m.def("loco_quantized_reduction",
&loco_quantized_reduction,
"LoCo Quantization and Reduction Kernel");
}