transformers

44cd6786 - Run the backward-only all-reduces only when a gradient can flow

Run the backward-only all-reduces only when a gradient can flow One helper, _all_reduce_backward, applies _AllReduceBackward only when grad is enabled and the input requires it, like the TP norm hooks (#49975). The MoE TP experts, the MLA rope projection and the EP inputs no longer run it at inference (~1.8us of host time per call in eager decode); the sites that already checked use the helper too. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>