What is the correct meaning of the cutoff_len parameter?

[baiyin]

Reminder

• I have read the README and searched the existing issues.

System Info

llama factory version: 0.9.1.dev0
platform : linux ubuntu
python: 3.11

Reproduction

nothing

Expected behavior

No response

Others

My understanding is that the cutoff_len parameter refers to the truncation of the input, without considering the model's output. This is based on the parameter description I saw in the code:

"The cutoff length of the tokenized inputs in the dataset."

However, the following discussion here seems to imply that the cutoff_len parameter is the sum of max_source_len and max_target_len. This is making me a bit confused.

Can someone help explain this?