[CUDA] Enable full cudagraph for FlashMLA (#18581)

Signed-off-by: luka <luka@neuralmagic.com>
This commit is contained in:
Luka Govedič
2025-06-13 14:12:26 -04:00
committed by GitHub
parent 1015296b79
commit 3597b06a4f
17 changed files with 452 additions and 219 deletions

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@@ -2,15 +2,16 @@
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import contextlib
import os
import weakref
from contextlib import ExitStack
import pytest
from tests.utils import wait_for_gpu_memory_to_clear
from vllm import LLM, SamplingParams
from vllm.config import CompilationConfig
from vllm.platforms import current_platform
MODEL = "Qwen/Qwen2-1.5B-Instruct"
@contextlib.contextmanager
def temporary_environ(env_vars):
@@ -31,64 +32,119 @@ def temporary_environ(env_vars):
os.environ[k] = v
@pytest.fixture(scope="module")
def full_cudagraph_llm():
@pytest.fixture(scope="class")
def llm_pair(request):
model = request.param
with temporary_environ({
"VLLM_USE_V1": "1",
"VLLM_FLASH_ATTN_VERSION": "3"
}):
return LLM(model=MODEL,
gpu_memory_utilization=0.3,
compilation_config=CompilationConfig(full_cuda_graph=True))
@pytest.fixture(scope="module")
def piecewise_llm():
with temporary_environ({
"VLLM_USE_V1": "1",
"VLLM_FLASH_ATTN_VERSION": "3"
}):
return LLM(model=MODEL,
gpu_memory_utilization=0.6,
compilation_config=CompilationConfig())
def generate_text(llm: LLM, batch_size: int, max_tokens: int):
prompts = ["Hi my name is"] * batch_size
sampling_params = SamplingParams(temperature=0.0,
max_tokens=max_tokens,
top_p=0.95)
return llm.generate(prompts, sampling_params)
full = LLM(
model=model,
gpu_memory_utilization=0.45,
trust_remote_code=True,
max_model_len=1024,
compilation_config=CompilationConfig(full_cuda_graph=True),
)
piecewise = LLM(
model=model,
gpu_memory_utilization=0.45,
trust_remote_code=True,
max_model_len=1024,
compilation_config=CompilationConfig(),
)
# PyTest caches the fixture values so we use weakref.proxy to enable GC
yield weakref.proxy(full), weakref.proxy(piecewise)
del full
del piecewise
wait_for_gpu_memory_to_clear(
devices=[0],
threshold_ratio=0.1,
)
@pytest.mark.parametrize(
"llm_pair",
[
# Model names for the llm_pair fixture
"deepseek-ai/DeepSeek-V2-Lite",
"Qwen/Qwen2-1.5B-Instruct"
],
indirect=True)
@pytest.mark.skipif(current_platform.get_device_capability() != (9, 0),
reason="Only Hopper GPUs support FlashAttention 3")
@pytest.mark.parametrize(("batch_size", "max_tokens"), [(1, 10), (7, 10),
(16, 10), (25, 10),
(32, 10), (45, 10),
(64, 10), (8, 5),
(8, 20), (8, 200)])
def test_full_cudagraph(batch_size, max_tokens, full_cudagraph_llm,
piecewise_llm):
reason="Only Hopper GPUs support FA3 and FlashMLA")
class TestFullCUDAGraph:
"""
Load full cudagraph model and piecewise model once, and at the same time to
reuse them across various test cases.
Use a class such that an llm pair is constructed once for all
batch_size/max_tokens combinations and released immediately after.
Test various batch sizes and max_tokens to ensure that the full cudagraph
compilation works for padded cases too.
Module-scope fixtures would stick around the whole time,
meaning there would be multiple LLM instances hogging memory simultaneously.
"""
piecewise_responses = generate_text(piecewise_llm,
batch_size=batch_size,
max_tokens=max_tokens)
full_cudagraph_responses = generate_text(full_cudagraph_llm,
batch_size=batch_size,
max_tokens=max_tokens)
# Check that all responses are the same
for i in range(len(piecewise_responses)):
assert piecewise_responses[i].outputs[
0].text == full_cudagraph_responses[i].outputs[0].text
@pytest.mark.parametrize(("batch_size", "max_tokens"), [
(1, 10),
(7, 10),
(16, 10),
(25, 10),
(32, 10),
(45, 10),
(64, 10),
(123, 10),
(8, 5),
(8, 30),
])
def test_full_cudagraph(self, batch_size, max_tokens,
llm_pair: tuple[LLM, LLM]):
"""
Test various batch sizes and max_tokens to ensure that the
full cudagraph compilation works for padded cases too.
"""
piecewise_llm, full_cudagraph_llm = llm_pair
prompts = ["Hello, my name is"] * batch_size
sampling_params = SamplingParams(temperature=0.0,
max_tokens=max_tokens,
top_p=0.95)
piecewise_responses = piecewise_llm.generate(prompts, sampling_params)
full_responses = full_cudagraph_llm.generate(prompts, sampling_params)
# Check that all responses are the same
for piecewise_res, full_res in zip(piecewise_responses,
full_responses):
assert piecewise_res.outputs[0].text == full_res.outputs[0].text
@pytest.mark.parametrize(
"model, supported",
[
("Qwen/Qwen2-1.5B-Instruct", True),
# MLA does not support capturing CUDA Graphs with size > max_num_seqs
("deepseek-ai/DeepSeek-V2-Lite", False),
])
@pytest.mark.skipif(current_platform.get_device_capability() != (9, 0),
reason="Only Hopper GPUs support FA3 and FlashMLA")
def test_lower_max_num_seqs(model, supported):
with temporary_environ({
"VLLM_USE_V1": "1",
"VLLM_FLASH_ATTN_VERSION": "3"
}), ExitStack() as stack:
if not supported:
stack.enter_context(pytest.raises(RuntimeError))
llm = LLM(model=model,
max_num_seqs=256,
trust_remote_code=True,
max_model_len=1024,
compilation_config=CompilationConfig(
full_cuda_graph=True,
cudagraph_capture_sizes=[64, 256, 512]))
llm.generate(["Hello, my name is"] * 10)
def test_full_cudagraph_with_invalid_backend():
@@ -97,5 +153,5 @@ def test_full_cudagraph_with_invalid_backend():
"VLLM_FLASH_ATTN_VERSION":
"2" #FA2 not supported with full_cuda_graph
}), pytest.raises(RuntimeError):
LLM(model=MODEL,
LLM(model="Qwen/Qwen2-1.5B-Instruct",
compilation_config=CompilationConfig(full_cuda_graph=True))

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@@ -4,7 +4,7 @@
Test the piecewise compilation with a simple model so that we
can exactly calculate the expected output and side effects.
"""
import pytest
import torch
from torch import nn
from torch.library import Library
@@ -14,6 +14,7 @@ from vllm.compilation.decorators import support_torch_compile
from vllm.config import (CompilationConfig, CompilationLevel, VllmConfig,
set_current_vllm_config)
from vllm.envs import VLLM_USE_V1
from vllm.forward_context import set_forward_context
from vllm.utils import direct_register_custom_op
global_counter = 0
@@ -76,7 +77,8 @@ class SillyModel(nn.Module):
return x
def _test_simple_piecewise_compile(*, use_inductor):
@pytest.mark.parametrize("use_inductor", [True, False])
def test_simple_piecewise_compile(use_inductor):
assert VLLM_USE_V1
vllm_config = VllmConfig(compilation_config=CompilationConfig(
@@ -99,7 +101,7 @@ def _test_simple_piecewise_compile(*, use_inductor):
num_backend_compilations=3, # num_piecewise_capturable_graphs_seen
num_cudagraph_captured=
6, # num_cudagraph_sizes * num_piecewise_capturable_graphs_seen
):
), set_forward_context({}, vllm_config=vllm_config):
model(inputs)
@@ -112,11 +114,3 @@ def _test_simple_piecewise_compile(*, use_inductor):
output = model(input)
assert global_counter == 2
assert torch.allclose(output.cpu(), torch.tensor([3., 1.]))
def test_simple_piecewise_compile_inductor():
_test_simple_piecewise_compile(use_inductor=True)
def test_simple_piecewise_compile_no_inductor():
_test_simple_piecewise_compile(use_inductor=False)

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@@ -11,6 +11,7 @@ initialized randomly with a fixed seed.
from dataclasses import dataclass
from typing import Any, Optional
import pytest
import torch
from torch import nn
from torch.library import Library
@@ -19,6 +20,7 @@ from vllm.compilation.counter import compilation_counter
from vllm.compilation.decorators import support_torch_compile
from vllm.config import (CompilationConfig, CompilationLevel, VllmConfig,
set_current_vllm_config)
from vllm.forward_context import set_forward_context
from vllm.utils import direct_register_custom_op
# create a library to hold the custom op
@@ -285,29 +287,32 @@ def run_model(llama_config,
vllm_config=vllm_config,
prefix="").eval().cuda()
B = 16 # max batch size
input_ids = torch.randint(0, llama_config.vocab_size, (B, )).cuda()
positions = torch.arange(B).cuda()
with set_forward_context({}, vllm_config=vllm_config):
B = 16 # max batch size
input_ids = torch.randint(0, llama_config.vocab_size, (B, )).cuda()
positions = torch.arange(B).cuda()
model(input_ids, positions)
model(input_ids[:2], positions[:2])
model(input_ids[:1], positions[:1])
model(input_ids, positions)
model(input_ids[:2], positions[:2])
model(input_ids[:1], positions[:1])
input_ids[:2].zero_()
output = model(input_ids[:2], positions[:2])
input_ids[:2].zero_()
output = model(input_ids[:2], positions[:2])
output = output.cpu()
output = output.cpu()
if llama_config.tractable_init:
expected_output = tractable_computation(input_ids[:2], positions[:2],
llama_config).cpu()
if llama_config.tractable_init:
expected_output = tractable_computation(input_ids[:2],
positions[:2],
llama_config).cpu()
assert torch.allclose(output, expected_output)
else:
return output.cpu()
assert torch.allclose(output, expected_output)
else:
return output.cpu()
def _test_toy_llama(*, use_inductor):
@pytest.mark.parametrize("use_inductor", [True, False])
def test_toy_llama(use_inductor: bool):
# compare output with and without piecewise compilation
llama_config = LlamaConfig(hidden_size=128,
@@ -379,14 +384,6 @@ def _test_toy_llama(*, use_inductor):
assert torch.allclose(outputs[0], outputs[i])
def test_toy_llama_inductor():
_test_toy_llama(use_inductor=True)
def test_toy_no_inductor():
_test_toy_llama(use_inductor=False)
@torch.inference_mode
def benchmark():
from triton.testing import do_bench

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@@ -667,42 +667,54 @@ def get_physical_device_indices(devices):
@_nvml()
def wait_for_gpu_memory_to_clear(devices: list[int],
threshold_bytes: int,
def wait_for_gpu_memory_to_clear(*,
devices: list[int],
threshold_bytes: Optional[int] = None,
threshold_ratio: Optional[float] = None,
timeout_s: float = 120) -> None:
assert threshold_bytes is not None or threshold_ratio is not None
# Use nvml instead of pytorch to reduce measurement error from torch cuda
# context.
devices = get_physical_device_indices(devices)
start_time = time.time()
while True:
output: dict[int, str] = {}
output_raw: dict[int, float] = {}
output_raw: dict[int, tuple[float, float]] = {}
for device in devices:
if current_platform.is_rocm():
dev_handle = amdsmi_get_processor_handles()[device]
mem_info = amdsmi_get_gpu_vram_usage(dev_handle)
gb_used = mem_info["vram_used"] / 2**10
gb_total = mem_info["vram_total"] / 2**10
else:
dev_handle = nvmlDeviceGetHandleByIndex(device)
mem_info = nvmlDeviceGetMemoryInfo(dev_handle)
gb_used = mem_info.used / 2**30
output_raw[device] = gb_used
output[device] = f'{gb_used:.02f}'
gb_total = mem_info.total / 2**30
output_raw[device] = (gb_used, gb_total)
output[device] = f'{gb_used:.02f}/{gb_total:.02f}'
print('gpu memory used (GB): ', end='')
print('gpu memory used/total (GiB): ', end='')
for k, v in output.items():
print(f'{k}={v}; ', end='')
print('')
if threshold_bytes is not None:
is_free = lambda used, total: used <= threshold_bytes / 2**30
threshold = f"{threshold_bytes/2**30} GiB"
else:
is_free = lambda used, total: used / total <= threshold_ratio
threshold = f"{threshold_ratio:.2f}"
dur_s = time.time() - start_time
if all(v <= (threshold_bytes / 2**30) for v in output_raw.values()):
if all(is_free(used, total) for used, total in output_raw.values()):
print(f'Done waiting for free GPU memory on devices {devices=} '
f'({threshold_bytes/2**30=}) {dur_s=:.02f}')
f'({threshold=}) {dur_s=:.02f}')
break
if dur_s >= timeout_s:
raise ValueError(f'Memory of devices {devices=} not free after '
f'{dur_s=:.02f} ({threshold_bytes/2**30=})')
f'{dur_s=:.02f} ({threshold=})')
time.sleep(5)