Optimize schedule

[hnyls2002]

Motivation

Modifications

Checklist

• Format your code according to the Contributor Guide.
• Add unit tests as outlined in the Contributor Guide.
• Update documentation as needed, including docstrings or example tutorials.

[hxer7963]

hi, @hnyls2002 @merrymercy.

I have been exploring the source code of the PrefillAdder class and the scheduler module within ModelTpServer::get_new_prefill_batch. It seems that the implementation reserves the maximum possible output token slots based on the estimated new_token_ratio before scheduling prefill requests.

However, I am curious about the motivation behind the scheduling strategy used by PrefillAdder and how it contributes to optimizing scheduling performance.

Could you provide some insights into these aspects?