DeepSpeed

870ae041 - Fixes for training models with bf16 + freshly initialized optimizer via `load_module_only` (#4141)

Fixes for training models with bf16 + freshly initialized optimizer via `load_module_only` (#4141) This PR makes some fixes to the case where we want to resume training from a DeepSpeed ZeRO checkpoint and initialize a new optimizer, while not using the old optimizer in the checkpoint or relying on its existence at all. in this situation, despite passing `load_module_only=True` and `load_optimizer_states=False` to `load_checkpoint()`, the previous behavior was that: - `self._load_zero_checkpoint` would still be called, which attempts to load from the (in this case, nonexistent) checkpoint files. This PR stops this function from being called if using `load_module_only=True` and `load_optimizer_states=False`. Alternatively, calling this function may be alright if `"load_from_fp32_weights": true` is set in the DeepSpeed ZeRO config (reference: https://github.com/microsoft/DeepSpeed/blob/ff7d5275f2aa916cb5f320e0d817154e96f9cdb6/deepspeed/runtime/engine.py#L733) but this parameter does not seem to be documented in the docs for ZeRO config dicts. - in `_load_checkpoint`, the following codeblock: ``` if self.optimizer is not None and self.fp16_enabled(): self.optimizer.refresh_fp32_params() ``` results in `self.optimizer.refresh_fp32_params()` being called only if using FP16. As a result, the FP32 optimizer state is never initialized from the 16-bit model weights. This PR removes the fp16-specific condition. Previously reported in: https://github.com/EleutherAI/gpt-neox/issues/947 https://github.com/EleutherAI/gpt-neox/issues/843 Should also close: https://github.com/microsoft/DeepSpeed/issues/4017 Fixes: #4944 and #4017 This caused problems for a freshly-converted LLama checkpoint, which did not contain optimizer states, when trying to train with this model as initialization. I have confirmed the following fixes prevent this behavior. cc @Quentin-Anthony @zhangir-azerbayev --------- Co-authored-by: Olatunji Ruwase <olruwase@microsoft.com> Co-authored-by: Logan Adams <114770087+loadams@users.noreply.github.com>