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53 changes: 53 additions & 0 deletions custom_ops/gpu_ops/helper.h
Original file line number Diff line number Diff line change
Expand Up @@ -151,6 +151,34 @@ inline int GetGPUComputeCapability(int id) {

#endif

#ifndef FP8_E4M3_MAX
#define FP8_E4M3_MAX 448.0
#endif

#ifndef DISPATCH_FLOAT_FP6_DTYPE
#define DISPATCH_FLOAT_FP6_DTYPE(pd_dtype, c_type, ...) \
switch (pd_dtype) { \
case phi::DataType::FLOAT32: { \
using c_type = float; \
__VA_ARGS__ \
break; \
} \
case phi::DataType::BFLOAT16: { \
using c_type = phi::dtype::bfloat16; \
__VA_ARGS__ \
break; \
} \
case phi::DataType::FLOAT16: { \
using c_type = phi::dtype::float16; \
__VA_ARGS__ \
break; \
} \
default: { \
PD_THROW("Only supported attr of input type in [fp32, fp16, bf16]."); \
} \
}
#endif

inline constexpr uint32_t next_pow_2(uint32_t const num) {
if (num <= 1)
return num;
Expand Down Expand Up @@ -573,3 +601,28 @@ inline bool GetMlaUseTensorcore() {
flags_mla_use_tensorcore && enable_mla_tensorcore;
return mla_use_tensorcore;
}

__device__ __forceinline__ float warpReduceMax(float value) {
value = fmaxf(value, __shfl_xor_sync(0xffffffff, value, 16));
value = fmaxf(value, __shfl_xor_sync(0xffffffff, value, 8));
value = fmaxf(value, __shfl_xor_sync(0xffffffff, value, 4));
value = fmaxf(value, __shfl_xor_sync(0xffffffff, value, 2));
value = fmaxf(value, __shfl_xor_sync(0xffffffff, value, 1));
return value;
}

__device__ __forceinline__ float blockReduceMax(float value) {
static __shared__ float warpLevelMaxs[WARP_SIZE];
const int laneId = threadIdx.x % WARP_SIZE;
const int warpId = threadIdx.x / WARP_SIZE;

value = warpReduceMax(value);

if (laneId == 0) warpLevelMaxs[warpId] = value;
__syncthreads();

value = (threadIdx.x < blockDim.x / WARP_SIZE) ? warpLevelMaxs[laneId] : 0;
if (warpId == 0) value = warpReduceMax(value);

return value;
}
243 changes: 217 additions & 26 deletions custom_ops/gpu_ops/quantization/common.cu
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,158 @@

#include "quantization/common.cuh"

// adapted from: https://github.com/sgl-project/sglang/blob/v0.5.2rc2/sgl-kernel/csrc/gemm/per_token_quant_fp8.cu

// ---------------------------------------------------------------------------
// 1. Warp‑local, no shared memory
// • One warp handles one token.
// • Eight tokens per 256‑thread CTA.
// ---------------------------------------------------------------------------
template <typename T, typename DST_DTYPE, int kTokensPerCTA = 8, int kVecSize = 16>
__global__ void per_token_quant_fp8_kernel(
const T* __restrict__ input,
DST_DTYPE* __restrict__ output_q,
float* __restrict__ output_s,
const float scale_ub,
const int64_t hidden_size,
const int64_t num_tokens) {
const int warp_id = threadIdx.x / WARP_SIZE; // 0‑7 (8 warps)
const int lane_id = threadIdx.x & (WARP_SIZE - 1); // 0‑31
const int token_id = blockIdx.x * kTokensPerCTA + warp_id;
if (token_id >= num_tokens) return;

// Global tensors for this token
const T* token_input = input + token_id * hidden_size;
DST_DTYPE* token_output = output_q + token_id * hidden_size;
float* token_scale = output_s + token_id;

//
// Pass-1: Perform a warp reduce to find the max_value of a token's hidden_size
//
float max_value = 0.f;
using vec_t = AlignedVector<T, kVecSize>;
const int32_t num_vec_elems = hidden_size / kVecSize;

for (int32_t i = lane_id; i < num_vec_elems; i += WARP_SIZE) {
vec_t input_vec;
Load(token_input + i * kVecSize, &input_vec);

#pragma unroll
for (uint32_t j = 0; j < kVecSize; ++j) {
max_value = fmaxf(max_value, fabsf(static_cast<float>(input_vec[j])));
}
}

float warp_max = warpReduceMax(max_value);
if (scale_ub > 0){
warp_max = fminf(warp_max, scale_ub);
}
float scale;
scale = warp_max / FP8_E4M3_MAX;
// Broadcast scale
if (lane_id == 0) {
token_scale[0] = scale;
}
float scale_inv = (scale == 0.f) ? 0.f : 1.0f / scale;

//
// Pass-2: quantize and write back
//
for (int i = lane_id; i < num_vec_elems; i += WARP_SIZE) {
vec_t input_vec;
Load(token_input + i * kVecSize, &input_vec);
DST_DTYPE output_arr[kVecSize];
#pragma unroll
for (uint32_t j = 0; j < kVecSize; ++j) {
float val = static_cast<float>(input_vec[j]) * scale_inv;
val = fmaxf(fminf(val, FP8_E4M3_MAX), -FP8_E4M3_MAX);
output_arr[j] = static_cast<DST_DTYPE>(val);
}
if constexpr (kVecSize == 16) {
*(uint4*)(token_output + i * kVecSize) = *(uint4*)output_arr;
} else {
// Use element-wise copy for vector size 8 to ensure correctness
for (int k = 0; k < kVecSize; ++k) {
token_output[i * kVecSize + k] = output_arr[k];
}
}
}
}

// ---------------------------------------------------------------------------
// 2. Baseline kernel (1 token / CTA, CUB block reduce)
// ---------------------------------------------------------------------------
template <typename T, typename DST_DTYPE, int kVecSize = 16>
__global__ void per_token_quant_fp8_small_batch_kernel(
const T* __restrict__ input,
DST_DTYPE* __restrict__ output_q,
float* __restrict__ output_s,
const float scale_ub,
const int64_t hidden_size,
const int64_t num_tokens) {
const int token_idx = blockIdx.x;
if (token_idx >= num_tokens) return;

const int tid = threadIdx.x;
const int block_dim = blockDim.x;

const T* token_input = input + token_idx * hidden_size;
DST_DTYPE* token_output = output_q + token_idx * hidden_size;

float max_value = 0.0f;

// Use template parameter for vector size
using vec_t = AlignedVector<T, kVecSize>;
const int32_t num_vec_elems = hidden_size / kVecSize;

// Find max using vectorized loads
for (int32_t i = tid; i < num_vec_elems; i += block_dim) {
vec_t input_vec;
Load(token_input + i * kVecSize, &input_vec);

#pragma unroll
for (uint32_t j = 0; j < kVecSize; ++j) {
float val = static_cast<float>(input_vec[j]);
max_value = fmaxf(max_value, fabsf(val));
}
}

max_value = blockReduceMax(max_value);
if (scale_ub > 0){
max_value = fminf(max_value, scale_ub);
}
__shared__ float scale;
if (tid == 0) {
scale = max_value / FP8_E4M3_MAX;
output_s[token_idx] = scale;
}
__syncthreads();

const float scale_inv = 1.0f / scale;

// Quantize using vectorized loads
for (int32_t i = tid; i < num_vec_elems; i += block_dim) {
vec_t input_vec;
Load(token_input + i * kVecSize, &input_vec);

DST_DTYPE output_arr[kVecSize];
#pragma unroll
for (uint32_t j = 0; j < kVecSize; ++j) {
float val = fmaxf(fminf(static_cast<float>(input_vec[j]) * scale_inv, FP8_E4M3_MAX), -FP8_E4M3_MAX);
output_arr[j] = static_cast<DST_DTYPE>(val);
}

if constexpr (kVecSize == 16) {
*(uint4*)(token_output + i * kVecSize) = *(uint4*)output_arr;
} else {
// Use element-wise copy for vector size 8 to ensure correctness
for (int k = 0; k < kVecSize; ++k) {
token_output[i * kVecSize + k] = output_arr[k];
}
}
}
}

namespace fastdeploy {

template <typename scalar_t, typename fp8_type>
Expand Down Expand Up @@ -179,39 +331,78 @@ void DynamicPerTokenScaledFp8Quant(paddle::Tensor &out, // [..., d]
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;
if (hidden_size % 8 == 0){
int device = 0;
cudaGetDevice(&device);
int sm_count = 0;
cudaDeviceGetAttribute(&sm_count, cudaDevAttrMultiProcessorCount, device);
const int TOKENS_PER_CTA = 8;
const bool use_warp_kernel = (num_tokens >= sm_count * 2 * TOKENS_PER_CTA);
const bool use_vec16 = (hidden_size % 16 == 0);
DISPATCH_FLOAT_FP6_DTYPE(input.dtype(), scalar_t, {
if (use_warp_kernel) {
// -------- warp‑local ---------------------------------------------------
constexpr int THREADS = TOKENS_PER_CTA * WARP_SIZE; // 256
dim3 grid((num_tokens + TOKENS_PER_CTA - 1) / TOKENS_PER_CTA);
dim3 block(THREADS);

if (use_vec16) {
per_token_quant_fp8_kernel<scalar_t, __nv_fp8_e4m3, TOKENS_PER_CTA, 16><<<grid, block, 0, stream>>>(
reinterpret_cast<const scalar_t*>(input.data<scalar_t>()),
reinterpret_cast<__nv_fp8_e4m3*>(out.data<fp8_t>()),
reinterpret_cast<float*>(scales.data<float>()),
scale_ub,
hidden_size,
num_tokens);
} else {
per_token_quant_fp8_kernel<scalar_t, __nv_fp8_e4m3, TOKENS_PER_CTA, 8><<<grid, block, 0, stream>>>(
reinterpret_cast<const scalar_t*>(input.data<scalar_t>()),
reinterpret_cast<__nv_fp8_e4m3*>(out.data<fp8_t>()),
reinterpret_cast<float*>(scales.data<float>()),
scale_ub,
hidden_size,
num_tokens);
}
} else {
// -------- baseline -----------------------------------------------------
constexpr int THREADS = 256;
dim3 grid(num_tokens);
dim3 block(THREADS);

if (use_vec16) {
per_token_quant_fp8_small_batch_kernel<scalar_t, __nv_fp8_e4m3, 16><<<grid, block, 0, stream>>>(
reinterpret_cast<const scalar_t*>(input.data<scalar_t>()),
reinterpret_cast<__nv_fp8_e4m3*>(out.data<fp8_t>()),
reinterpret_cast<float*>(scales.data<float>()),
scale_ub,
hidden_size,
num_tokens);
} else {
per_token_quant_fp8_small_batch_kernel<scalar_t, __nv_fp8_e4m3, 8><<<grid, block, 0, stream>>>(
reinterpret_cast<const scalar_t*>(input.data<scalar_t>()),
reinterpret_cast<__nv_fp8_e4m3*>(out.data<fp8_t>()),
reinterpret_cast<float*>(scales.data<float>()),
scale_ub,
hidden_size,
num_tokens);
}
}
});
return;
}
case paddle::DataType::BFLOAT16: {
using scalar_t = phi::dtype::bfloat16;

dim3 const grid(num_tokens);
dim3 const block(std::min(hidden_size, 1024));

DISPATCH_FLOAT_FP6_DTYPE(input.dtype(), scalar_t, {
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)
Expand Down
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