Scaling RLHF
Scaling RLHF to large models presents challenges due to computational requirements. Here are some strategies that can be implemented:
- Distributed training: This involves partitioning the training workload across multiple devices – typically GPUs or TPUs – by employing data parallelism, model parallelism, or pipeline parallelism. In data parallelism, the same model is replicated across devices, and each replica processes a different mini-batch of data. Gradients are averaged and synchronized after each step. On the other hand, model parallelism splits the model itself across multiple devices, enabling the training of architectures that are too large to fit on a single device. Finally, pipeline parallelism further divides the model into sequential stages across devices, which are then trained in a pipelined fashion to improve throughput. Frameworks such as DeepSpeed and Megatron-LM provide infrastructure for managing these complex parallelization schemes...