ROOT CAUSE of 3100ms adam_child: adam_update_kernel and grad_norm_finalize_kernel
were shared between post_aux_child and adam_update/forward children. On Hopper,
CUfunction sharing across child graphs corrupts kernel state.
Fix: load utility cubin from separate CUmodule for post_aux child, giving it
isolated adam_update_post_aux, grad_norm_finalize_post_aux, and scale_f32_post_aux
handles. Zero cross-child CUfunction sharing for these kernels.
Also: convert memset_zeros to raw cuMemsetD8Async in IQN (3 calls), IQL (1),
Attention (1) — eliminates cudarc device_ptr_mut() overhead during graph capture.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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