Main KV round-trips byte-perfect yet output is garbage, so add the two
unverified components:
1. NSA INDEXER-K round-trip (level 2): hash the device index_k_with_scale_buffer
at backup (_backup_indexer_from_device_per_layer) and reload (NSA
load_to_device_per_layer, after _load_indexer), keyed by host-slot fingerprint
+ layer, with khash+nz. The indexer selects which tokens attention attends
(top-k); if it corrupts on reload -> wrong selection -> garbage even with
correct main KV.
2. FORWARD-side per-layer hashes (level 3, eager extend path only, cuda-graph
guarded): attn-input, attn-output (pre-residual), topk_indices (the indexer's
selection output -- direct consumer of the indexer-K), and MoE-input, in the
DeepseekV2/GlmMoeDsa decoder layer forward. Localizes where a reload forward
diverges: topk diverges => indexer-K cache; attn-out diverges (topk ok) =>
main KV/page mapping; moe-in diverges (attn-out ok) => residual/MoE.
Analyzer compares indexer reload vs backup (host_fp keyed) + flags zero/degenerate
hidden states per stage. Level 3 (SGLANG_CP_HICACHE_KV_TRACE=3) captures everything.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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