vllm/tests/worker/test_profile.py

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import torch
from vllm.engine.arg_utils import EngineArgs
from vllm.utils import get_distributed_init_method, get_ip, get_open_port
from vllm.worker.cache_engine import CacheEngine
from vllm.worker.worker import Worker
def test_gpu_memory_profiling():
# Tests the gpu profiling that happens in order to determine the number of
# KV cache blocks that we can allocate on the GPU.
# This test mocks the maximum available gpu memory so that it can run on
# any gpu setup.
# Set up engine args to build a worker.
engine_args = EngineArgs(model="facebook/opt-125m",
dtype="half",
load_format="dummy")
engine_config = engine_args.create_engine_config()
engine_config.cache_config.num_gpu_blocks = 1000
engine_config.cache_config.num_cpu_blocks = 1000
# Create the worker.
distributed_init_method = get_distributed_init_method(
get_ip(), get_open_port())
worker = Worker(
model_config=engine_config.model_config,
parallel_config=engine_config.parallel_config,
scheduler_config=engine_config.scheduler_config,
device_config=engine_config.device_config,
cache_config=engine_config.cache_config,
load_config=engine_config.load_config,
local_rank=0,
rank=0,
distributed_init_method=distributed_init_method,
is_driver_worker=True,
)
# Load the model so we can profile it
worker.init_device()
worker.load_model()
# Set 10GiB as the total gpu ram to be device-agnostic
def mock_mem_info():
current_usage = torch.cuda.memory_stats(
)["allocated_bytes.all.current"]
mock_total_bytes = 10 * 1024**3
free = mock_total_bytes - current_usage
return (free, mock_total_bytes)
from unittest.mock import patch
with patch("torch.cuda.mem_get_info", side_effect=mock_mem_info):
gpu_blocks, _ = worker.determine_num_available_blocks()
# Peak vram usage by torch should be 0.7077 GiB
# Non-torch allocations should be 0.0079 GiB
# 9.0 GiB should be the utilization target
# 8.2843 GiB should be available for the KV cache
block_size = CacheEngine.get_cache_block_size(
engine_config.cache_config, engine_config.model_config,
engine_config.parallel_config)
expected_blocks = (8.2843 * 1024**3) // block_size
# Check within a small tolerance for portability
# Hardware, kernel, or dependency changes could all affect memory
# utilization
assert abs(gpu_blocks - expected_blocks) < 5