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FastDeploy/custom_ops/gpu_ops/quantization/common.cu
2025-06-29 23:29:37 +00:00

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// adapted from: https://github.com/vllm-project/vllm/blob/118ff921118cc81061a2af865a1e13840ceb6792/csrc/quantization/cutlass_w8a8/c3x/cutlass_gemm_caller.cuh
#include "quantization/common.cuh"
namespace fastdeploy {
template <typename scalar_t, typename fp8_type>
__global__ void scaled_fp8_quant_kernel(fp8_type *__restrict__ out,
const scalar_t *__restrict__ input,
const float *__restrict__ scale,
int64_t num_elems) {
int tid = blockDim.x * blockIdx.x + threadIdx.x;
// Invert the scale so that we can use multiplications to avoid expensive
// division.
const float inverted_scale = 1.0f / (*scale);
scaled_fp8_conversion_vec<scalar_t, true>(
out, input, inverted_scale, num_elems, tid, blockDim.x * gridDim.x);
}
template <typename scalar_t, typename fp8_type>
__global__ void dynamic_per_token_scaled_fp8_quant_kernel(
fp8_type *__restrict__ out, float *__restrict__ scale,
scalar_t const *__restrict__ input, float scale_ub, const int hidden_size) {
int const tid = threadIdx.x;
int const token_idx = blockIdx.x;
// Use int64 to avoid overflowing an int32 when calculating this offset
int64_t offset = static_cast<int64_t>(token_idx) * hidden_size;
scalar_t const *__restrict__ token_input = &input[offset];
fp8_type *__restrict__ token_output = &out[offset];
// For vectorization, token_input and token_output pointers need to be
// aligned at 8-byte and 4-byte addresses respectively.
bool const can_vectorize = hidden_size % 4 == 0;
float absmax_val = 0.0f;
if (can_vectorize) {
absmax_val = thread_max_vec(token_input, hidden_size, tid, blockDim.x);
} else {
for (int i = tid; i < hidden_size; i += blockDim.x) {
float const x = static_cast<float>(token_input[i]);
absmax_val = max(absmax_val, fabs(x));
}
}
using BlockReduce = cub::BlockReduce<float, 1024>;
__shared__ typename BlockReduce::TempStorage reduceStorage;
float const block_absmax_val_maybe =
BlockReduce(reduceStorage).Reduce(absmax_val, cub::Max{}, blockDim.x);
__shared__ float token_scale;
if (tid == 0) {
if (scale_ub > 0) {
token_scale = min(block_absmax_val_maybe, scale_ub);
} else {
token_scale = block_absmax_val_maybe;
}
// token scale computation
// token_scale = max(token_scale / 448.f,
// min_scaling_factor<fp8_type>::val());
token_scale = token_scale / 448.f;
scale[token_idx] = token_scale;
}
__syncthreads();
// Note that we don't use inverted scales so we can match FBGemm impl.
if (can_vectorize) {
scaled_fp8_conversion_vec<scalar_t, false>(
token_output, token_input, token_scale, hidden_size, tid, blockDim.x);
} else {
for (int i = tid; i < hidden_size; i += blockDim.x) {
token_output[i] = scaled_fp8_conversion<false, fp8_type>(
static_cast<float>(token_input[i]), token_scale);
}
}
}
} // namespace fastdeploy
void StaticScaledFp8Quant(paddle::Tensor &out, // [..., d]
paddle::Tensor const &input, // [..., d]
paddle::Tensor const &scale) // [1]
{
PD_CHECK(out.dtype() == paddle::DataType::FLOAT8_E4M3FN);
using fp8_t = phi::dtype::float8_e4m3fn;
auto rank = input.dims().size();
int64_t num_tokens = input.numel() / input.dims()[rank - 1];
int64_t num_elems = input.numel();
dim3 grid(num_tokens);
dim3 block(1024);
cudaStream_t stream = input.stream();
switch (input.dtype()) {
case paddle::DataType::FLOAT32: {
using scalar_t = float;
fastdeploy::scaled_fp8_quant_kernel<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(out.data<fp8_t>(), input.data<scalar_t>(),
scale.data<float>(), num_elems);
break;
}
case paddle::DataType::FLOAT16: {
using scalar_t = phi::dtype::float16;
fastdeploy::scaled_fp8_quant_kernel<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(out.data<fp8_t>(), input.data<scalar_t>(),
scale.data<float>(), num_elems);
break;
}
case paddle::DataType::BFLOAT16: {
using scalar_t = phi::dtype::bfloat16;
fastdeploy::scaled_fp8_quant_kernel<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(out.data<fp8_t>(), input.data<scalar_t>(),
scale.data<float>(), num_elems);
break;
}
default:
PD_THROW("Only supported attr of input type in [fp32, fp16, bf16].");
}
}
void DynamicScaledFp8Quant(paddle::Tensor &out, // [..., d]
paddle::Tensor const &input, // [..., d]
paddle::Tensor &scale) // [1]
{
PD_CHECK(out.dtype() == paddle::DataType::FLOAT8_E4M3FN);
using fp8_t = phi::dtype::float8_e4m3fn;
auto rank = input.dims().size();
int64_t num_tokens = input.numel() / input.dims()[rank - 1];
int64_t num_elems = input.numel();
dim3 grid(num_tokens);
dim3 block(1024);
cudaStream_t stream = input.stream();
switch (input.dtype()) {
case paddle::DataType::FLOAT32: {
using scalar_t = float;
fastdeploy::segmented_max_reduction<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(scale.data<float>(),
input.data<scalar_t>(), num_elems);
fastdeploy::scaled_fp8_quant_kernel<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(out.data<fp8_t>(), input.data<scalar_t>(),
scale.data<float>(), num_elems);
break;
}
case paddle::DataType::FLOAT16: {
using scalar_t = phi::dtype::float16;
fastdeploy::segmented_max_reduction<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(scale.data<float>(),
input.data<scalar_t>(), num_elems);
fastdeploy::scaled_fp8_quant_kernel<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(out.data<fp8_t>(), input.data<scalar_t>(),
scale.data<float>(), num_elems);
break;
}
case paddle::DataType::BFLOAT16: {
using scalar_t = phi::dtype::bfloat16;
fastdeploy::segmented_max_reduction<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(scale.data<float>(),
input.data<scalar_t>(), num_elems);
fastdeploy::scaled_fp8_quant_kernel<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(out.data<fp8_t>(), input.data<scalar_t>(),
scale.data<float>(), num_elems);
break;
}
default:
PD_THROW("Only supported attr of input type in [fp32, fp16, bf16].");
}
}
void DynamicPerTokenScaledFp8Quant(paddle::Tensor &out, // [..., d]
paddle::Tensor const &input, // [..., d]
paddle::Tensor &scales, float scale_ub) {
PD_CHECK(input.is_contiguous());
PD_CHECK(out.is_contiguous());
PD_CHECK(out.dtype() == paddle::DataType::FLOAT8_E4M3FN);
using fp8_t = phi::dtype::float8_e4m3fn;
auto rank = input.dims().size();
int const hidden_size = input.dims()[rank - 1];
int const num_tokens = input.numel() / hidden_size;
dim3 const grid(num_tokens);
dim3 const block(std::min(hidden_size, 1024));
cudaStream_t stream = input.stream();
switch (input.dtype()) {
case paddle::DataType::FLOAT32: {
using scalar_t = float;
fastdeploy::dynamic_per_token_scaled_fp8_quant_kernel<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(out.data<fp8_t>(), scales.data<float>(),
input.data<scalar_t>(), scale_ub,
hidden_size);
break;
}
case paddle::DataType::FLOAT16: {
using scalar_t = phi::dtype::float16;
fastdeploy::dynamic_per_token_scaled_fp8_quant_kernel<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(out.data<fp8_t>(), scales.data<float>(),
input.data<scalar_t>(), scale_ub,
hidden_size);
break;
}
case paddle::DataType::BFLOAT16: {
using scalar_t = phi::dtype::bfloat16;
fastdeploy::dynamic_per_token_scaled_fp8_quant_kernel<scalar_t, fp8_t>
<<<grid, block, 0, stream>>>(out.data<fp8_t>(), scales.data<float>(),
input.data<scalar_t>(), scale_ub,
hidden_size);
break;
}
default:
PD_THROW("Only supported attr of input type in [fp32, fp16, bf16].");
}
}
PD_BUILD_STATIC_OP(static_scaled_fp8_quant)
.Inputs({"out", "input", "scale"})
.Outputs({"out_q"})
.SetInplaceMap({{"out", "out_q"}})
.SetKernelFn(PD_KERNEL(StaticScaledFp8Quant));
PD_BUILD_STATIC_OP(dynamic_scaled_fp8_quant)
.Inputs({"out", "input", "scale"})
.Outputs({"out_q", "out_scale"})
.SetInplaceMap({{"out", "out_q"},
{"scale", "out_scale"}})
.SetKernelFn(PD_KERNEL(DynamicScaledFp8Quant));
PD_BUILD_STATIC_OP(dynamic_per_token_scaled_fp8_quant)
.Inputs({"out", "input", "scale"})
.Attrs({"scale_ub: float"})
.Outputs({"out_q"})
.SetInplaceMap({{"out", "out_q"}})
.SetKernelFn(PD_KERNEL(DynamicPerTokenScaledFp8Quant));