sglang.0.4.8.post1/sglang/test/srt/test_block_int8.py

223 lines
7.4 KiB
Python

import itertools
import unittest
import torch
from sglang.srt.layers.activation import SiluAndMul
from sglang.srt.layers.moe.fused_moe_triton.fused_moe import fused_moe
from sglang.test.test_utils import CustomTestCase
# For test
def native_per_token_group_quant_int8(x, group_size, eps=1e-10, dtype=torch.int8):
"""Function to perform per-token-group quantization on an input tensor `x` using native torch.
It converts the tensor values into float8 values and returns the
quantized tensor along with the scaling factor used for quantization.
Note that only `torch.float8_e4m3fn` is supported for now.
"""
assert (
x.shape[-1] % group_size == 0
), "the last dimension of `x` cannot be divisible by `group_size`"
assert x.is_contiguous(), "`x` is not contiguous"
iinfo = torch.iinfo(dtype)
int8_min = iinfo.min
int8_max = iinfo.max
x_ = x.reshape(x.numel() // group_size, group_size)
amax = x_.abs().max(dim=-1, keepdim=True)[0].clamp(min=eps).to(torch.float32)
x_s = amax / int8_max
x_q = (x_ / x_s).clamp(min=int8_min, max=int8_max).to(dtype)
x_q = x_q.reshape(x.shape)
x_s = x_s.reshape(x.shape[:-1] + (x.shape[-1] // group_size,))
return x_q, x_s
# For test
def native_w8a8_block_int8_matmul(A, B, As, Bs, block_size, output_dtype=torch.float16):
"""This function performs matrix multiplication with block-wise quantization using native torch.
It takes two input tensors `A` and `B` with scales `As` and `Bs`.
The output is returned in the specified `output_dtype`.
"""
A = A.to(torch.float32)
B = B.to(torch.float32)
assert A.shape[-1] == B.shape[-1]
assert B.ndim == 2 and B.is_contiguous() and Bs.ndim == 2
assert len(block_size) == 2
block_n, block_k = block_size[0], block_size[1]
assert (A.shape[-1] + block_k - 1) // block_k == As.shape[-1]
assert A.shape[:-1] == As.shape[:-1]
M = A.numel() // A.shape[-1]
N, K = B.shape
origin_C_shape = A.shape[:-1] + (N,)
A = A.reshape(M, A.shape[-1])
As = As.reshape(M, As.shape[-1])
n_tiles = (N + block_n - 1) // block_n
k_tiles = (K + block_k - 1) // block_k
assert n_tiles == Bs.shape[0]
assert k_tiles == Bs.shape[1]
C_shape = (M, N)
C = torch.zeros(C_shape, dtype=torch.float32, device=A.device)
A_tiles = [A[:, i * block_k : min((i + 1) * block_k, K)] for i in range(k_tiles)]
B_tiles = [
[
B[
j * block_n : min((j + 1) * block_n, N),
i * block_k : min((i + 1) * block_k, K),
]
for i in range(k_tiles)
]
for j in range(n_tiles)
]
C_tiles = [C[:, j * block_n : min((j + 1) * block_n, N)] for j in range(n_tiles)]
As_tiles = [As[:, i : i + 1] for i in range(k_tiles)]
for i in range(k_tiles):
for j in range(n_tiles):
a = A_tiles[i]
b = B_tiles[j][i]
c = C_tiles[j]
s = As_tiles[i] * Bs[j][i]
c[:, :] += torch.matmul(a, b.t()) * s
C = C.reshape(origin_C_shape).to(output_dtype)
return C
# For test
def torch_w8a8_block_int8_moe(a, w1, w2, w1_s, w2_s, score, topk, block_shape):
"""This function performs fused moe with block-wise quantization using native torch."""
B, D = a.shape
a = a.view(B, -1, D).repeat(1, topk, 1).reshape(-1, D)
out = torch.zeros(B * topk, w2.shape[1], dtype=a.dtype, device=a.device)
score = torch.softmax(score, dim=-1, dtype=torch.float32)
topk_weight, topk_ids = torch.topk(score, topk)
topk_weight = topk_weight.view(-1)
topk_ids = topk_ids.view(-1)
_, block_k = block_shape[0], block_shape[1]
a_q, a_s = native_per_token_group_quant_int8(a, block_k)
for i in range(w1.shape[0]):
mask = topk_ids == i
if mask.sum():
inter_out = native_w8a8_block_int8_matmul(
a_q[mask], w1[i], a_s[mask], w1_s[i], block_shape, output_dtype=a.dtype
)
act_out = SiluAndMul().forward_native(inter_out)
act_out_q, act_out_s = native_per_token_group_quant_int8(act_out, block_k)
act_out = act_out.to(torch.float32)
out[mask] = native_w8a8_block_int8_matmul(
act_out_q, w2[i], act_out_s, w2_s[i], block_shape, output_dtype=a.dtype
)
return (
out.view(B, -1, w2.shape[1]) * topk_weight.view(B, -1, 1).to(out.dtype)
).sum(dim=1)
class TestW8A8BlockINT8FusedMoE(CustomTestCase):
DTYPES = [torch.half, torch.bfloat16]
M = [1, 33, 64, 222]
N = [128, 1024]
K = [256, 4096]
E = [8, 24]
TOP_KS = [2, 6]
# BLOCK_SIZE = [[64, 64], [64, 128], [128, 64], [128, 128]]
BLOCK_SIZE = [[128, 128]]
SEEDS = [0]
@classmethod
def setUpClass(cls):
if not torch.cuda.is_available():
raise unittest.SkipTest("CUDA is not available")
torch.set_default_device("cuda")
def _w8a8_block_int8_fused_moe(self, M, N, K, E, topk, block_size, dtype, seed):
torch.manual_seed(seed)
# NOTE(HandH1998): to avoid overflow when out_dtype = torch.half
factor_for_scale = 1e-2
int8_info = torch.iinfo(torch.int8)
int8_max, int8_min = int8_info.max, int8_info.min
a = torch.randn((M, K), dtype=dtype) / 10
w1_fp32 = (torch.rand((E, 2 * N, K), dtype=torch.float32) - 0.5) * 2 * int8_max
w1 = w1_fp32.clamp(min=int8_min, max=int8_max).to(torch.int8)
w2_fp32 = (torch.rand((E, K, N), dtype=torch.float32) - 0.5) * 2 * int8_max
w2 = w2_fp32.clamp(min=int8_min, max=int8_max).to(torch.int8)
block_n, block_k = block_size[0], block_size[1]
n_tiles_w1 = (2 * N + block_n - 1) // block_n
n_tiles_w2 = (K + block_n - 1) // block_n
k_tiles_w1 = (K + block_k - 1) // block_k
k_tiles_w2 = (N + block_k - 1) // block_k
w1_s = (
torch.rand((E, n_tiles_w1, k_tiles_w1), dtype=torch.float32)
* factor_for_scale
)
w2_s = (
torch.rand((E, n_tiles_w2, k_tiles_w2), dtype=torch.float32)
* factor_for_scale
)
score = torch.randn((M, E), dtype=dtype)
with torch.inference_mode():
out = fused_moe(
a,
w1,
w2,
score,
topk,
renormalize=False,
use_int8_w8a8=True,
w1_scale=w1_s,
w2_scale=w2_s,
block_shape=block_size,
)
ref_out = torch_w8a8_block_int8_moe(
a, w1, w2, w1_s, w2_s, score, topk, block_size
)
self.assertTrue(
torch.mean(torch.abs(out.to(torch.float32) - ref_out.to(torch.float32)))
/ torch.mean(torch.abs(ref_out.to(torch.float32)))
< 0.02
)
def test_w8a8_block_int8_fused_moe(self):
for params in itertools.product(
self.M,
self.N,
self.K,
self.E,
self.TOP_KS,
self.BLOCK_SIZE,
self.DTYPES,
self.SEEDS,
):
with self.subTest(
M=params[0],
N=params[1],
K=params[2],
E=params[3],
topk=params[4],
block_size=params[5],
dtype=params[6],
seed=params[7],
):
self._w8a8_block_int8_fused_moe(*params)
if __name__ == "__main__":
unittest.main(verbosity=2)