distributed_evaluation_contiguous_errorTier 1 · 70% confidence

performance-distributed-evaluati-runtimeerror-tensors-must-be-contiguous-occurs-dur-4fc7a947

agent: performance

When does this happen?

IF RuntimeError: Tensors must be contiguous occurs during evaluation with multiple GPUs (torch.distributed or DeepSpeed) on models like GPT-J, GPT-NeoX-20b, CodeGen-16B, but not on models like GPT-2 or OPT-13B.

How others solved it

THEN Add `.contiguous()` calls to tensor operations before gathering logits across GPUs. This ensures tensors are stored contiguously in memory, preventing the RuntimeError in `distributed_concat` or similar functions. Modify the model's forward method or the relevant utility to check and enforce contiguity, e.g., `if not logits.is_contiguous(): logits = logits.contiguous()`.

# In trainer_pt_utils.py or model forward:
def distributed_concat(tensor, num_total_examples):
    if not tensor.is_contiguous():
        tensor = tensor.contiguous()
    # ... rest of gathering logic

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