vllm/tests/utils_/test_mem_utils.py
Cyrus Leung d31f7844f8
[Misc] Move utils to avoid conflicts with stdlib, and move tests (#27169)
Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>
2025-10-19 05:20:55 -07:00

64 lines
2.3 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import torch
from vllm_test_utils.monitor import monitor
from vllm.utils.mem_utils import MemorySnapshot, memory_profiling
from ..utils import create_new_process_for_each_test
@create_new_process_for_each_test()
def test_memory_profiling():
# Fake out some model loading + inference memory usage to test profiling
# Memory used by other processes will show up as cuda usage outside of torch
from vllm.distributed.device_communicators.cuda_wrapper import CudaRTLibrary
lib = CudaRTLibrary()
# 512 MiB allocation outside of this instance
handle1 = lib.cudaMalloc(512 * 1024 * 1024)
baseline_snapshot = MemorySnapshot()
# load weights
weights = torch.randn(128, 1024, 1024, device="cuda", dtype=torch.float32)
weights_memory = 128 * 1024 * 1024 * 4 # 512 MiB
def measure_current_non_torch():
free, total = torch.cuda.mem_get_info()
current_used = total - free
current_torch = torch.cuda.memory_reserved()
current_non_torch = current_used - current_torch
return current_non_torch
with (
memory_profiling(
baseline_snapshot=baseline_snapshot, weights_memory=weights_memory
) as result,
monitor(measure_current_non_torch) as monitored_values,
):
# make a memory spike, 1 GiB
spike = torch.randn(256, 1024, 1024, device="cuda", dtype=torch.float32)
del spike
# Add some extra non-torch memory 256 MiB (simulate NCCL)
handle2 = lib.cudaMalloc(256 * 1024 * 1024)
# this is an analytic value, it is exact,
# we only have 256 MiB non-torch memory increase
measured_diff = monitored_values.values[-1] - monitored_values.values[0]
assert measured_diff == 256 * 1024 * 1024
# Check that the memory usage is within 5% of the expected values
# 5% tolerance is caused by cuda runtime.
# we cannot control cuda runtime in the granularity of bytes,
# which causes a small error (<10 MiB in practice)
non_torch_ratio = result.non_torch_increase / (256 * 1024 * 1024) # noqa
assert abs(non_torch_ratio - 1) <= 0.05
assert result.torch_peak_increase == 1024 * 1024 * 1024
del weights
lib.cudaFree(handle1)
lib.cudaFree(handle2)