NVIDIA / NVIDIA/apex

Use fp16 performance decrease

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Dominant language
Python
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Description

Hi, I use apex op_level O2, and do some cast in some places, but the performance decrease.

image

Any way to find where the precision decrease caused by fp16 (or by casting float to float16)?

Besides, will FFNLayer(3 * hidden_size, hidden_size, 2, dropout_prob)only accept float16 input when using amp?
image

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Research direction

Start with the Apex AMP op_level O2 configuration and the FFNLayer(3 * hidden_size, hidden_size, 2, dropout_prob) call shown in the report. Reproduce the fp16 performance decrease while checking the reported casts and input precision; done means identifying whether the slowdown comes from fp16 or casting and clarifying the accepted input type.

Written by the indexing model from the issue text.

Assessment

Tech stack
python, pytorch
Domain
machine-learning, performance
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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