Activation Recompute Stable docs: @docs/training/activation-recomputation.md Card: @skills/nemo-mbridge-perf-activation-recompute/card.yaml <!-- Guidance refreshed: 2026-08-12. -- Activation recompute (activation checkpointing) trades additional forward work during backward for lower retained-activation memory. The useful checkpoint boundary depends on the model architecture, attention backend, parallelism, and the tensor that actually drives the per-rank peak. Quick Decision Guide 1. Confirm the pressure is real allocation, not allocator fragmentation. Compare with on every rank. 2. Keep an…