#
# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
# Copyright 2023 The vLLM team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# This file is a part of the vllm-ascend project.
#

import os

import torch
from vllm import LLM, SamplingParams
from vllm.utils.mem_constants import GiB_bytes

os.environ["VLLM_USE_MODELSCOPE"] = "True"
os.environ["VLLM_WORKER_MULTIPROC_METHOD"] = "spawn"


def main():
    prompt = "How are you?"

    free, total = torch.npu.mem_get_info()
    print(f"Free memory before sleep: {free / 1024**3:.2f} GiB")
    # record npu memory use baseline in case other process is running
    used_bytes_baseline = total - free
    llm = LLM("Qwen/Qwen2.5-0.5B-Instruct", enable_sleep_mode=True)
    sampling_params = SamplingParams(temperature=0, max_tokens=10)
    output = llm.generate(prompt, sampling_params)

    llm.sleep(level=1)

    free_npu_bytes_after_sleep, total = torch.npu.mem_get_info()
    print(f"Free memory after sleep: {free_npu_bytes_after_sleep / 1024**3:.2f} GiB")
    used_bytes = total - free_npu_bytes_after_sleep - used_bytes_baseline
    # now the memory usage should be less than the model weights
    # (0.5B model, 1GiB weights)
    assert used_bytes < 1 * GiB_bytes

    llm.wake_up()
    output2 = llm.generate(prompt, sampling_params)
    # cmp output
    assert output[0].outputs[0].text == output2[0].outputs[0].text


if __name__ == "__main__":
    main()
