{
  "schema": "vortex-exact-attention-architecture-model",
  "version": 1,
  "status": "projected_not_measured",
  "baseline": {
    "device": "NVIDIA GB10", "architecture": "sm_121a", "tokens": 37810,
    "heads": 56, "head_dimension": 128, "mainloop_p50_ms": 237.089,
    "grid": [296, 56, 1], "block": [32, 4, 1], "kv_iterations": 591,
    "stages": 2, "registers_per_thread": 255, "dynamic_shared_kib": 32,
    "occupancy_percent": [16.65, 16.83], "no_eligible_cycles_percent": 63.53,
    "l2_hit_percent": 98.85, "memory_throughput_percent": 31.74
  },
  "hard_gates": {
    "mainloop_model_must_beat_ms": 220, "preferred_model_below_ms": 190,
    "byte_exact": true, "material_score_tensor": false,
    "material_local_spills": false,
    "kv_tile_order": "strictly_increasing_0_through_590",
    "pv_accumulation": "two_ordered_k32_fp16_mma_then_ordered_fp32_ro_add"
  },
  "model_basis": {
    "kind": "heuristic_rejection_screen",
    "formula": "baseline minus assumed recovered fraction of no-eligible region plus handoff budget",
    "exact_preparation_components_ms": {"p1_entry": 12.33, "k_mean": 2.37, "k_quant": 3.83, "p2_v": 6.39},
    "exact_preparation_ms": [25, 28],
    "unresolved": ["full attention kernel resources and latency", "DSM placement and latency"]
  },
  "phase2a_capability_measurements": {
    "status": "passed_for_isolated_aligned_prototype",
    "date": "2026-08-26",
    "candidate": "VEA-B",
    "geometry": {"threads": 320, "warps": 10, "epochs": 591, "dynamic_shared_bytes": 51200},
    "selected_handoff": "cuda_block_scope_mbarrier",
    "registers_per_thread": {"handoff": 96, "qk_role": 54, "pv_role": 138, "combined_ownership": 139},
    "local_bytes_per_thread": 0,
    "ptxas_spill_loads": 0,
    "ptxas_spill_stores": 0,
    "resident_ctas_per_sm": 1,
    "timing_ms": {
      "mbarrier_only_p50": 0.07680000364780426,
      "mbarrier_only_p95": 0.07887999713420868,
      "payload_p50": 1.8749439716339111,
      "payload_p95": 1.8794736385345459,
      "budget": 11.85445
    },
    "handoff_validation": {"checksum": 4671090, "publication_errors": 0, "deterministic_repeat": true},
    "tensor_issue": {"positive_overlap_blocks": 48, "total_blocks": 48, "p50_overlap_ratio": 0.999992875970649, "combined_p50_ms": 0.12707199901342392},
    "sanitizer": {"mbarrier_memcheck_errors": 0, "mbarrier_racecheck_hazards": 0, "tensor_memcheck_errors": 0, "tensor_racecheck_hazards": 0},
    "rejected_primitive": {"name": "inline_ptx_named_barrier", "racecheck_hazards": 5},
    "canonical_fixture": {"shape": [1, 37810, 56, 128], "dtype": "bfloat16", "output_sha256": "4c666c20f5f8f651158a2ced33ccff08f3bada07665c595b99008d171db30574", "reload_verified": true},
    "attention_kernel_implemented": false,
    "attention_latency_measured": false
  },
  "candidates": [
    {
      "id": "VEA-A", "name": "Q64 split-D intra-CTA pipeline", "recommended_order": 3,
      "geometry": {"q": 64, "k": 64, "d": 128, "threads": 256, "warps": 8},
      "ownership": {"qk_fragments": "warps_1_2", "m_d": "warps_1_2", "output_accumulation": "warps_3_6_split_d64", "load_control": "warps_0_7"},
      "handoff": {"mechanism": "two_slot_shared_ring_named_barriers", "payload": "fp8_probability_bytes_plus_fp32_ro_rescale", "bounded_tile_local": true, "consumer_order": "strict_epoch_order", "qk_and_pv_fragments_simultaneously_live": true, "same_warp": false},
      "registers_per_thread": {"load": [32, 48], "qk_softmax": [96, 128], "pv_output": [88, 120], "control": [32, 64]},
      "shared_kib": {"q": 8, "k_double": 16, "v_double": 16, "score_double": 8, "metadata": [3, 4], "total": [51, 52]},
      "registers_per_cta_uniform_projection": 32768,
      "resident_ctas_per_sm_projected": 1, "synchronization_ms_projected": [8, 18],
      "recovered_no_eligible_fraction": [0.22, 0.35],
      "mainloop_ms_projected": [192, 222], "complete_attention_ms_projected": [217, 250],
      "capability_dependencies": ["named_barrier_cost", "INT8_FP8_overlap"],
      "structural_difference": "RO is removed from QK warps and split by D; m/d and scores are removed from PV warps"
    },
    {
      "id": "VEA-B", "name": "Q128 paired QK/PV owner pipeline", "recommended_order": 1,
      "geometry": {"q": 128, "k": 64, "d": 128, "threads": 320, "warps": 10},
      "ownership": {"qk_fragments": "warps_2_5", "m_d": "warps_2_5", "output_accumulation": "warps_6_9", "load_control": "warps_0_1"},
      "handoff": {"mechanism": "two_slot_role_asymmetric_cuda_block_scope_mbarriers", "payload": "fp8_probability_bytes_plus_fp32_ro_rescale_and_final_reciprocal", "bounded_tile_local": true, "consumer_order": "strict_epoch_order", "qk_and_pv_fragments_simultaneously_live": true, "same_warp": false},
      "registers_per_thread": {"k_producer": [32, 48], "v_producer": [40, 56], "qk_softmax": [96, 128], "pv_output": [144, 176]},
      "logical_role_weighted_registers": 39000, "registers_per_cta_uniform_projection": 56320, "compiled_register_limit_per_thread": 200,
      "shared_kib": {"unaliased": [66, 68], "alias_saving": 16, "total": [50, 52]},
      "resident_ctas_per_sm_projected": 1, "synchronization_ms_projected": [6, 15],
      "recovered_no_eligible_fraction": [0.30, 0.42],
      "mainloop_ms_projected": [180, 207], "complete_attention_ms_projected": [205, 235],
      "capability_dependencies": ["full_kernel_exactness", "full_kernel_compiled_resources", "full_kernel_latency"],
      "structural_difference": "QK/softmax and RO/PV have permanent disjoint owners; P1/P2 may feed slots but are not standalone boundaries"
    },
    {
      "id": "VEA-C", "name": "two-CTA DSM ownership split", "recommended_order": 2,
      "geometry": {"q": 128, "k": 64, "d": 128, "ctas": 2, "threads_total": 384, "warps_total": 12},
      "ownership": {"qk_fragments": "producer_cta_warps_1_4", "m_d": "producer_cta_warps_1_4", "output_accumulation": "consumer_cta_warps_1_4", "load_control": "producer_and_consumer_warps_0_5"},
      "handoff": {"mechanism": "two_slot_dsm_ring_cluster_barriers", "payload": "fp8_probability_bytes_plus_fp32_ro_rescale_and_final_reciprocal", "bounded_tile_local": true, "consumer_order": "strict_epoch_order", "qk_and_pv_fragments_simultaneously_live": true, "same_warp": false, "same_cta": false},
      "registers_per_thread": {"producer_load_publish": [32, 48], "qk_softmax": [96, 128], "consumer_v": [40, 56], "pv_output": [144, 176], "consumer_store": [40, 64]},
      "registers_per_cluster_projected": [50000, 60000], "shared_kib": {"producer": 50, "consumer": 18, "cluster_total": 68},
      "resident_cluster_projection": "unverified", "synchronization_ms_projected": [12, 30],
      "recovered_no_eligible_fraction": [0.38, 0.50],
      "mainloop_ms_projected": [174, 210], "complete_attention_ms_projected": [199, 238],
      "capability_dependencies": ["DSM_support", "cluster_simultaneous_residency", "DSM_round_trip_latency", "INT8_FP8_overlap"],
      "structural_difference": "QK/softmax state and RO/PV state reside in separate CTAs and cross an explicit DSM byte handoff"
    }
  ],
  "decision": {"recommended_prototype": "VEA-B", "selected_handoff": "cuda_block_scope_mbarrier", "phase2a_capability_passed": true, "isolated_aligned_prototype_authorized": true, "fallback": "VEA-A", "conditional_second": "VEA-C", "kernel_implementation_started": false, "production_dispatch_changed": false}
}