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vLLM/tests/quantization/test_online.py
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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""Tests online quantization."""
from types import SimpleNamespace
from typing import cast
import pytest
import torch
from torch.distributed import ProcessGroup
from tests.quantization.utils import (
_test_online_quant_peak_mem_impl,
is_quant_method_supported,
)
from vllm import _custom_ops as ops
from vllm._aiter_ops import rocm_aiter_ops
from vllm._custom_ops import scaled_fp4_quant
from vllm.model_executor.layers.linear import UnquantizedLinearMethod
from vllm.model_executor.layers.quantization.online.fp8 import (
Fp8PerBlockOnlineLinearMethod,
Fp8PerBlockOnlineMoEMethod,
Fp8PerTensorOnlineLinearMethod,
Fp8PerTensorOnlineMoEMethod,
_fp8_channel_scale,
_fp8_quant_per_channel,
_fp8_scale,
_is_tp_sharded,
)
from vllm.model_executor.layers.quantization.online.int8 import Int8OnlineMoEMethod
from vllm.model_executor.layers.quantization.online.mxfp4 import (
Mxfp4OnlineLinearMethod,
Mxfp4OnlineMoEMethod,
)
from vllm.model_executor.layers.quantization.online.nvfp4 import (
Nvfp4OnlineMoEMethod,
_quantize_moe_weight_to_nvfp4,
)
from vllm.model_executor.layers.quantization.utils import quant_utils
from vllm.model_executor.layers.quantization.utils.quant_utils import (
amax_for_moe_weight_quant,
amax_for_tp_weight_quant,
weight_amax,
)
from vllm.platforms import current_platform
from vllm.utils.flashinfer import has_flashinfer_trtllm_fused_moe
if current_platform.is_rocm():
from vllm.platforms.rocm import on_gfx942, on_gfx950
else:
def on_gfx950() -> bool:
return False
def on_gfx942() -> bool:
return False
DEVICE = current_platform.device_type
@pytest.mark.skipif(
not is_quant_method_supported("fp8"),
reason="FP8 is not supported on this GPU type.",
)
@pytest.mark.parametrize(
"quant_scheme,online_quant_args,expected_linear_cls,expected_moe_cls",
[
# simple case - quantization='fp8_per_tensor'
(
"fp8_per_tensor",
None,
Fp8PerTensorOnlineLinearMethod,
Fp8PerTensorOnlineMoEMethod,
),
# simple case - quantization='fp8_per_block'
(
"fp8_per_block",
None,
Fp8PerBlockOnlineLinearMethod,
Fp8PerBlockOnlineMoEMethod,
),
# quantization='online' with per-layer-kind overrides
(
"online",
{
"linear": "fp8_per_block",
"moe": "fp8_per_tensor",
},
Fp8PerBlockOnlineLinearMethod,
Fp8PerTensorOnlineMoEMethod,
),
# ignore with direct layer name
(
"fp8_per_tensor",
# qkv_proj is fused from q_proj/k_proj/v_proj, so currently the
# ignore regex must match the unfused shard names
# TODO(future PR): also make 're:.*qkv_proj.*' work
{"ignore": ["model.layers.1.self_attn.o_proj", "re:.*[qkv]_proj"]},
Fp8PerTensorOnlineLinearMethod,
Fp8PerTensorOnlineMoEMethod,
),
(
"mxfp4",
None,
Mxfp4OnlineLinearMethod,
Mxfp4OnlineMoEMethod,
),
],
)
@pytest.mark.parametrize(
"use_rocm_aiter", [True, False] if current_platform.is_rocm() else [False]
)
def test_online_quantization(
vllm_runner,
quant_scheme: str,
online_quant_args: dict | None,
expected_linear_cls,
expected_moe_cls,
use_rocm_aiter: bool,
monkeypatch,
) -> None:
"""
Tests that online quantization frontend configuration works -
selecting quant schemes, overriding quant schemes by type, ignoring
layers.
Does not test performance, peak memory usage, etc.
"""
# TODO: Relax this condition once there is a native MXFP4_MXFP4
# linear/moe backend supported on cuda.
if quant_scheme == "mxfp4" and not (on_gfx950() or on_gfx942()):
pytest.skip("mxfp4 online quantization is only tested on AMD gfx942, gfx950.")
if current_platform.is_rocm():
monkeypatch.setenv("VLLM_ROCM_USE_AITER", "1" if use_rocm_aiter else "0")
rocm_aiter_ops.refresh_env_variables()
if current_platform.is_xpu() and quant_scheme == "fp8_per_block":
pytest.skip("Skip test for online fp8_per_block on XPU platform.")
# `LLM.apply_model` requires pickling a function.
monkeypatch.setenv("VLLM_ALLOW_INSECURE_SERIALIZATION", "1")
# a tiny model with both dense and MoE layers
model_name = "ibm-granite/granite-3.0-1b-a400m-base"
runner_kwargs = dict(
quantization=quant_scheme,
enforce_eager=True,
)
if online_quant_args is not None:
runner_kwargs["quantization_config"] = online_quant_args
with vllm_runner(
model_name,
**runner_kwargs,
) as llm:
def check_model(model):
# checks further down in the test case are hardcoded for this
# model
assert model_name == "ibm-granite/granite-3.0-1b-a400m-base"
o_proj = model.model.layers[0].self_attn.o_proj
moe = model.model.layers[0].block_sparse_moe.experts
# o_proj and moe in layer 0 are always quantized (never ignored)
# because of how we craft the test case inputs
assert isinstance(o_proj.quant_method, expected_linear_cls)
if moe is not None:
assert isinstance(moe._quant_method, expected_moe_cls)
if quant_scheme == "mxfp4":
# Packed e2m1 values, two per byte.
assert o_proj.weight.dtype == torch.uint8
elif current_platform.is_cuda() or current_platform.is_xpu():
assert o_proj.weight.dtype == torch.float8_e4m3fn
elif current_platform.is_rocm():
assert o_proj.weight.dtype == current_platform.fp8_dtype()
else:
pytest.skip("Only runs on CUDA and ROCm.")
# Verify ignored layers are unquantized.
if isinstance(online_quant_args, dict) and "ignore" in online_quant_args:
# only .*1.self_attn_o_proj is skipped
for layer_idx in range(len(model.model.layers)):
o_proj = model.model.layers[layer_idx].self_attn.o_proj
if layer_idx == 1:
assert isinstance(o_proj.quant_method, UnquantizedLinearMethod)
else:
assert isinstance(o_proj.quant_method, expected_linear_cls)
# every .*self_attn.qkv_proj is skipped
for layer_idx in range(len(model.model.layers)):
qkv_proj = model.model.layers[layer_idx].self_attn.qkv_proj
assert isinstance(qkv_proj.quant_method, UnquantizedLinearMethod)
llm.apply_model(check_model)
outputs = llm.generate_greedy(["Hello my name is"], max_tokens=4)
print(outputs[0][1])
@pytest.mark.skipif(
not (
current_platform.is_cuda()
and current_platform.is_device_capability_family(100)
and has_flashinfer_trtllm_fused_moe()
),
reason="nvfp4_per_token needs a Blackwell (SM100) GPU + FlashInfer TRTLLM MoE.",
)
def test_online_nvfp4_per_token_moe(vllm_runner, monkeypatch) -> None:
"""Online NVFP4 quantizes the MoE and leaves dense layers unquantized."""
monkeypatch.setenv("VLLM_ALLOW_INSECURE_SERIALIZATION", "1")
with vllm_runner(
"ibm-granite/granite-3.0-1b-a400m-base",
quantization="nvfp4_per_token",
enforce_eager=True,
) as llm:
def check_model(model):
layer = model.model.layers[0]
assert isinstance(
layer.block_sparse_moe.experts._quant_method, Nvfp4OnlineMoEMethod
)
assert isinstance(
layer.self_attn.o_proj.quant_method, UnquantizedLinearMethod
)
llm.apply_model(check_model)
outputs = llm.generate_greedy(["Hello my name is"], max_tokens=4)
print(outputs[0][1])
def _patch_max_reduce(monkeypatch, full_amax) -> None:
"""Stand in for the TP/EP MAX all-reduce, returning the unsharded amax."""
expected = cast(ProcessGroup, object())
stub = SimpleNamespace(device_group=expected)
monkeypatch.setattr(quant_utils, "get_tp_group", lambda: stub)
monkeypatch.setattr(quant_utils, "get_ep_group", lambda: stub)
def fake_all_reduce(tensor, op, group):
assert op == torch.distributed.ReduceOp.MAX
assert group is expected
tensor.copy_(full_amax)
monkeypatch.setattr(torch.distributed, "all_reduce", fake_all_reduce)
def test_is_tp_sharded_false_when_scale_is_already_global() -> None:
"""Replicated and column-parallel-with-channel-scales need no collective."""
replicated = SimpleNamespace(
tp_size=4,
input_size=64,
output_size=32,
input_size_per_partition=64,
output_size_per_partition=32,
)
assert not _is_tp_sharded(replicated)
column = SimpleNamespace(
tp_size=4,
input_size=64,
output_size=32,
input_size_per_partition=64,
output_size_per_partition=8,
)
assert not _is_tp_sharded(column, reduces_output_dim=False)
assert _is_tp_sharded(column)
def _quantize_linear(weight, scheme, is_sharded):
if scheme == "per_tensor":
amax = weight_amax(weight).reshape(1)
scale = _fp8_scale(amax_for_tp_weight_quant(amax, is_sharded))
return ops.scaled_fp8_quant(weight, scale=scale)[0], scale
amax = weight_amax(weight, dim=-1, keepdim=True)
scale = _fp8_channel_scale(amax_for_tp_weight_quant(amax, is_sharded))
return _fp8_quant_per_channel(weight, scale), scale
@pytest.mark.skipif(
not is_quant_method_supported("fp8"),
reason="FP8 is not supported on this GPU type.",
)
@pytest.mark.parametrize("scheme", ["per_tensor", "per_channel"])
@pytest.mark.parametrize("shard_dim", [0, 1])
def test_online_linear_tp_weight_quant_matches_unsharded(
monkeypatch, scheme: str, shard_dim: int
) -> None:
"""TP shards pack the same FP8 values and scales as the unsharded weight."""
torch.manual_seed(0)
weight = torch.randn(32, 64, device=DEVICE, dtype=torch.bfloat16)
weight[-1, -1] = 64.0
full_weight, full_scale = _quantize_linear(weight, scheme, False)
# Per-channel scales reduce only the input dim, so a column (dim 0) shard
# already matches without a collective.
is_sharded = scheme == "per_tensor" or shard_dim == 1
if is_sharded:
full_amax = (
weight_amax(weight).reshape(1)
if scheme == "per_tensor"
else weight_amax(weight, dim=-1, keepdim=True)
)
_patch_max_reduce(monkeypatch, full_amax)
shard_size = weight.shape[shard_dim] // 2
shard = weight.narrow(shard_dim, 0, shard_size).contiguous()
tp_weight, tp_scale = _quantize_linear(shard, scheme, is_sharded)
assert torch.equal(tp_weight, full_weight.narrow(shard_dim, 0, shard_size))
if scheme == "per_channel" and shard_dim == 0:
assert torch.equal(tp_scale, full_scale.narrow(0, 0, shard_size))
else:
assert torch.equal(tp_scale, full_scale)
def _quantize_moe(weight, scheme, moe_tp_size):
if scheme == "nvfp4":
return _quantize_moe_weight_to_nvfp4(weight, moe_tp_size)
if scheme == "per_tensor":
amax = weight_amax(weight.flatten(1), dim=-1)
scale = _fp8_scale(amax_for_moe_weight_quant(amax, moe_tp_size))
quant = lambda w, s: ops.scaled_fp8_quant(w, scale=s)[0] # noqa: E731
else:
amax = weight_amax(weight, dim=-1, keepdim=True)
scale = _fp8_channel_scale(amax_for_moe_weight_quant(amax, moe_tp_size))
quant = _fp8_quant_per_channel
qweight = torch.stack([quant(w, s) for w, s in zip(weight, scale)])
return qweight, scale
@pytest.mark.parametrize("scheme", ["per_tensor", "per_channel", "nvfp4"])
def test_online_moe_tp_weight_quant_matches_ep(monkeypatch, scheme: str) -> None:
"""TP shards of w2 pack the same values and scales as full experts."""
if scheme == "nvfp4":
if (
not (
current_platform.is_cuda()
and current_platform.is_device_capability_family(100)
)
or current_platform.is_xpu()
):
pytest.skip("NVFP4 weight quantization needs a Blackwell (SM100) GPU.")
elif not is_quant_method_supported("fp8"):
pytest.skip("FP8 is not supported on this GPU type.")
torch.manual_seed(0)
weight = torch.randn(2, 32, 32, device=DEVICE, dtype=torch.bfloat16)
weight[:, -1, -1] = torch.tensor([32.0, 64.0], device=DEVICE)
ep_out = _quantize_moe(weight, scheme, 1)
full_amax = (
weight_amax(weight, dim=-1, keepdim=True)
if scheme == "per_channel"
else weight_amax(weight.flatten(1), dim=-1).to(torch.float32)
)
_patch_max_reduce(monkeypatch, full_amax)
# w2 is sharded along its last (intermediate) dim.
shard_size = weight.shape[2] // 2
tp_out = _quantize_moe(weight[:, :, :shard_size], scheme, 2)
packing = 2 if scheme == "nvfp4" else 1
assert torch.equal(tp_out[0], ep_out[0][:, :, : shard_size // packing])
if scheme == "nvfp4":
assert torch.equal(tp_out[1], ep_out[1][:, :, : shard_size // 16])
assert torch.equal(tp_out[-1], ep_out[-1])
def test_online_int8_moe_w2_scale_matches_unsharded(monkeypatch) -> None:
"""Int8 MoE w2 reduces over the sharded intermediate dim."""
torch.manual_seed(0)
w13 = torch.randn(2, 16, 8, dtype=torch.bfloat16)
w2 = torch.randn(2, 8, 16, dtype=torch.bfloat16)
w2[:, -1, -1] = 64.0
def quantize(w2_in, moe_tp_size):
layer = torch.nn.Module()
layer.w13_weight = torch.nn.Parameter(w13, requires_grad=False)
layer.w2_weight = torch.nn.Parameter(w2_in, requires_grad=False)
layer.num_experts = layer.local_num_experts = w13.shape[0]
method = SimpleNamespace(moe=SimpleNamespace(tp_size=moe_tp_size))
Int8OnlineMoEMethod._quantize_weights(method, layer)
return layer.w2_weight, layer.w2_scale
full_weight, full_scale = quantize(w2, 1)
_patch_max_reduce(monkeypatch, weight_amax(w2, dim=-1))
shard_size = w2.shape[2] // 2
tp_weight, tp_scale = quantize(w2[:, :, :shard_size].contiguous(), 2)
assert torch.equal(tp_weight, full_weight[:, :, :shard_size])
assert torch.equal(tp_scale, full_scale)
@pytest.mark.skipif(
not (
current_platform.is_cuda() and current_platform.is_device_capability_family(100)
),
reason="NVFP4 weight quantization needs a Blackwell (SM100) GPU.",
)
def test_online_nvfp4_quantizes_original_expert_weights() -> None:
torch.manual_seed(0)
weight = torch.randn(2, 32, 32, device="cuda", dtype=torch.bfloat16)
quantized, block_scale, global_decode_scale = _quantize_moe_weight_to_nvfp4(weight)
global_encode_scale = 1.0 / global_decode_scale
expected = [
scaled_fp4_quant(
expert_weight,
expert_scale,
is_sf_swizzled_layout=False,
)
for expert_weight, expert_scale in zip(
weight,
global_encode_scale,
strict=True,
)
]
assert torch.equal(
quantized,
torch.stack([expert_weight for expert_weight, _ in expected]),
)
assert torch.equal(
block_scale,
torch.stack([expert_scale for _, expert_scale in expected]),
)
@pytest.mark.skipif(
not is_quant_method_supported("fp8"),
reason="FP8 is not supported on this GPU type.",
)
def test_online_quant_peak_mem(
vllm_runner,
caplog_mp_spawn,
monkeypatch,
) -> None:
_test_online_quant_peak_mem_impl(
"fp8_per_tensor", vllm_runner, caplog_mp_spawn, monkeypatch
)
@pytest.mark.skipif(
not is_quant_method_supported("fp8"),
reason="FP8 is not supported on this GPU type.",
)
def test_online_quant_load_format_dummy(
vllm_runner,
monkeypatch,
caplog,
) -> None:
with vllm_runner(
"ibm-granite/granite-3.0-1b-a400m-base",
quantization="fp8_per_tensor",
enforce_eager=True,
load_format="dummy",
) as llm:
outputs = llm.generate_greedy(["The future of AI is"], max_tokens=4)
print(outputs[0][1])