deepspeedai / deepspeedai/DeepSpeedExamples

zero3 and enable hybrid engine are not suitable for llama2, how to solve it?

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Description

In my experiment, I found that if I use zero3 and enable hybrid engine setting, the Actor will generate repeat token or nothing during stage 3 (PPO) training. Here is an example:

image

Besides, I took some other experiments:
Experiment 1: use the zero2 and enable hybrid engine, which is fine.

Experiment 2: use the zero3 and disenable hybrid engine, which is fine.

Experiment 3: I tested the OPT model, which is fine in zero3, and enable hybrid engine setting.

I'm confused by this phenomenon and want to know how to fix it. That said, due to time and GPU memory constraints, I want to use zero3 and enable hybrid engine settings.

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Research direction

Start by reproducing the reported stage 3 PPO behavior with Llama2, ZeRO-3, and hybrid engine enabled, then compare it with the working ZeRO-2, hybrid-disabled, and OPT configurations. Trace the Actor generation path and determine the cause of repeated or empty tokens; done means identifying a reproducible fix and confirming normal generation in the failing configuration.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
machine-learning
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
30/100

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