DeepSeek-V3/inference/kernel.py
2025-04-08 22:46:24 -03:00

135 lines
4.2 KiB
Python

import torch
import triton
import triton.language as tl
@triton.jit
def weight_dequant_kernel(
q_ptr, s_ptr, out_ptr, M, N,
stride_qm, stride_qn, stride_sm, stride_sn,
stride_om, stride_on,
BLOCK_SIZE_M: tl.constexpr, BLOCK_SIZE_N: tl.constexpr
):
"""
Triton kernel for FP8 weight dequantization.
out = q * s
"""
pid = tl.program_id(axis=0)
num_blocks_n = tl.cdiv(N, BLOCK_SIZE_N)
pid_m = pid // num_blocks_n
pid_n = pid % num_blocks_n
offs_m = pid_m * BLOCK_SIZE_M + tl.arange(0, BLOCK_SIZE_M)
offs_n = pid_n * BLOCK_SIZE_N + tl.arange(0, BLOCK_SIZE_N)
mask_m = offs_m < M
mask_n = offs_n < N
q_ptrs = q_ptr + offs_m[:, None] * stride_qm + offs_n[None, :] * stride_qn
s_ptrs = s_ptr + offs_m[:, None] * stride_sm + offs_n[None, :] * stride_sn
out_ptrs = out_ptr + offs_m[:, None] * stride_om + offs_n[None, :] * stride_on
q = tl.load(q_ptrs, mask=mask_m[:, None] & mask_n[None, :], other=0)
s = tl.load(s_ptrs, mask=mask_m[:, None] & mask_n[None, :], other=1)
out = q.to(tl.float32) * s.to(tl.float32)
tl.store(out_ptrs, out, mask=mask_m[:, None] & mask_n[None, :])
@triton.jit
def fp8_gemm_kernel(
a_ptr, b_ptr, c_ptr, M, N, K,
stride_am, stride_ak, stride_bk, stride_bn,
stride_cm, stride_cn,
BLOCK_SIZE_M: tl.constexpr, BLOCK_SIZE_N: tl.constexpr, BLOCK_SIZE_K: tl.constexpr
):
"""
Triton kernel for FP8 GEMM (General Matrix Multiply)
c = a @ b
"""
pid = tl.program_id(axis=0)
num_blocks_n = tl.cdiv(N, BLOCK_SIZE_N)
pid_m = pid // num_blocks_n
pid_n = pid % num_blocks_n
offs_m = pid_m * BLOCK_SIZE_M + tl.arange(0, BLOCK_SIZE_M)
offs_n = pid_n * BLOCK_SIZE_N + tl.arange(0, BLOCK_SIZE_N)
mask_m = offs_m < M
mask_n = offs_n < N
c_ptrs = c_ptr + offs_m[:, None] * stride_cm + offs_n[None, :] * stride_cn
acc = tl.zeros((BLOCK_SIZE_M, BLOCK_SIZE_N), dtype=tl.float32)
for k in range(0, K, BLOCK_SIZE_K):
offs_k = k + tl.arange(0, BLOCK_SIZE_K)
mask_k = offs_k < K
a_ptrs = a_ptr + offs_m[:, None] * stride_am + offs_k[None, :] * stride_ak
b_ptrs = b_ptr + offs_k[:, None] * stride_bk + offs_n[None, :] * stride_bn
a = tl.load(a_ptrs, mask=mask_m[:, None] & mask_k[None, :], other=0)
b = tl.load(b_ptrs, mask=mask_k[:, None] & mask_n[None, :], other=0)
acc += tl.dot(a, b)
tl.store(c_ptrs, acc, mask=mask_m[:, None] & mask_n[None, :])
def dequantize_weights(q_weight: torch.Tensor, scale: torch.Tensor, block_size=16) -> torch.Tensor:
"""
Dequantizes FP8 weights using provided scaling factors.
Args:
q_weight (torch.Tensor): Quantized weight matrix (e.g. float8).
scale (torch.Tensor): Scaling factors.
block_size (int): Block size used in the kernel.
Returns:
torch.Tensor: Dequantized weight matrix (float32).
"""
assert q_weight.shape == scale.shape, "Mismatched shapes between quantized weights and scales."
M, N = q_weight.shape
output = torch.empty_like(q_weight, dtype=torch.float32)
grid = (triton.cdiv(M, block_size) * triton.cdiv(N, block_size),)
weight_dequant_kernel[grid](
q_weight, scale, output,
M, N,
q_weight.stride(0), q_weight.stride(1),
scale.stride(0), scale.stride(1),
output.stride(0), output.stride(1),
block_size, block_size
)
return output
def fp8_gemm(a: torch.Tensor, b: torch.Tensor, block_size=16) -> torch.Tensor:
"""
Performs GEMM on FP8 dequantized matrices using Triton.
Args:
a (torch.Tensor): Left matrix (float32).
b (torch.Tensor): Right matrix (float32).
block_size (int): Block size for tiling.
Returns:
torch.Tensor: Output matrix (float32).
"""
assert a.shape[1] == b.shape[0], "Incompatible matrix dimensions."
M, K = a.shape
_, N = b.shape
output = torch.empty((M, N), dtype=torch.float32)
grid = (triton.cdiv(M, block_size) * triton.cdiv(N, block_size),)
fp8_gemm_kernel[grid](
a, b, output,
M, N, K,
a.stride(0), a.stride(1),
b.stride(0), b.stride(1),
output.stride(0), output.stride(1),
block_size, block_size, block_size
)
return output