[BUG] Some situations encountered after enabling multiple workers

[josangmi]

Feel free to ask any kind of questions in the issues page, but please use English since other users may find your questions valuable.

Describe the bug
A clear and concise description of what the bug is.
直接用 --workers 2 会出现
WARNING: You must pass the application as an import string to enable 'reload' or 'workers' 然后会退出进程，

To Reproduce
Steps to reproduce the behavior:
需要修改：
原代码： uvicorn.run(app, host=host, port=int(port), workers=args.workers, log_level="info")
修改后代码： uvicorn.run("tools.api:app", host=host, port=int(port), workers=args.workers, log_level="info")
然后就可以启动了。
但是并没有加载两个模型，理解不能同时进行推理，如果希望加载模型同时推理的话，有优化的办法吗？
还有多显卡的话，好像不能device=auto
Expected behavior
A clear and concise description of what you expected to happen.
多workers 启动之后使用会出现

接下来不会改了。 谢谢。
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Additional context
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[PoTaTo-Mika]

可以尝试单机多端口进行并发。

[keepgoingwang]

原因有可能是开启多进程后，args参数是由主进程获取的，子进程无法获取主进程变量。不知道后续是否会修补这个bug

[Stardust-minus]

#515 Change title to English.