# Round 40: 14-Item `llama.cpp-feature-adaptive-kv-stream-rocm` Audit & Apple M5 Metal Port
## Executive Summary
Evaluated all 14 candidate optimizations (`#1..#14`) from `llama.cpp-feature-adaptive-kv-stream-rocm` (`/Users/dawn/Downloads/llama.cpp-feature-adaptive-kv-stream-rocm.zip`) against `vendor/strata` on Apple M5 (`10-core GPU`, `24 GB unified memory`):
- **7 Optimizations Shipped / Verified Active (`#1, #2, #3, #6, #8, #11, #13` + `#7, #14` already native in Strata)**
- **5 Micro-Architectural Candidates Rejected with Measured Negative-Result Proofs on M5 (`#4, #5, #9, #10, #12`)**
All shipped kernels pass their standalone parity suites (`gdn_prompt_parity`, `comb_fold_parity 0 mtpdefer`, `comb_fold_parity 0 topk`, `route_parity --ab`, `gdn_parity`, `qsa_parity --paired`) with `exit_code = 0`, and end-to-end 48-layer teacher-forced evaluation on `K512-iq2_xs-metal.gguf` (`eval_tf_chat_json.txt`, 159 prompt + 64 eval tokens) achieves **`mean_kld = 0.000479` (`median_kld = 0.000004`), `100.00%` top-1 agreement (`64/64`), and `100%` identical `GEN_IDS`** (`0.000830` with `route_topk` delayed-softmax, `100.00%` top-1 agreement).
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## Summary Table (`#1..#14`)
| # | Optimization | Target Files | Parity | M5 Measured Result | Verdict |
|---|---|---|---|---|---|
| **#1** | Chunked WY GDN Prefill on Matrix Units (`matmul2d` + fp16 `(hi, lo)` split) | `gdn_prompt.metal`, `window.cpp`, `prompt_chain.inc` | `o` rel L2 `4.0e-7`, `state` rel L2 `3.4e-7` vs `gdn_scanr_4` & fp64; 48-layer KLD `0.000479`, top-1 `100.0%` | **`0.717–0.734x` (`-26.6% to -28.3%`, `-53.6 ms` per 2K chunk; full GDN `269.3 -> 216.6 ms`, `0.805x`)** | **SHIPPED** |
| **#2** | Combined `(a + 1)`-Row MTP Catch-Up + Draft Step-0 Batch (`defer_catchup`, `QSA_LAST_Q`) | `qsa.metal`, `window.cpp`, `comb_fold_parity.cpp` | `same_tile=1` bitwise (`max\|dR\|=0, max\|dq\|=0`), `same_tile=0` `max\|dR\|=4.77e-7`, KV bitwise | **`a=1`: `-26.8%` (`635.8 -> 465.5 us`, `19 -> 11` disp); `a=2`: `-20.5%`; `a=3`: `-20.1%`** | **SHIPPED** |
| **#3** | Zero-Copy Dual-Slot GDN Recurrent State & History Rollback (`dual2` / `spec1`) | `gdn.metal`, `window.cpp`, `prompt_chain.inc`, `gdn_parity.cpp` | `100%` bitwise exact across all 88 `(ntok, commit, plane)` cases + `ring rollback bitwise: yes PASS` | **Eliminates `Window::fold()` (`2.0–2.2 ms`) 100% of the time (`n_keep=1` and `n_keep=T`); `-0.14 to -0.58 ms`/round net** | **SHIPPED** |
| **#4** | `0x6400` IEEE-754 Mantissa Trick for `int8` & `uint4` (`pd_i8x2` / `pd_u4x2`) | `qsa*.metal`, `dense_mm.metal`, `moe_mm.metal` | `100%` bitwise (`memcmp == 0`) | **`1.015–1.036x` slower** on QSA (`1.00x` on `dq_f16` / `moe_mm`): M5 hardware `int8 -> float` cvt is free | **REJECTED** |
| **#5** | In-Register Butterfly FWHT (`D=256`) for `int4` QSA V-Cache & `Q2_0` Outliers | `dev/fwht_bench.metal` | `int4` rel L2 `23.3% -> 8.85%` on outliers (`int8+FWHT`: `1.68% -> 0.49%`, `0` overhead) | `int4` V-cache still `15–18x` worse than `int8` (`10.8%` vs `0.59%` Gaussian); retained `int8` | **REJECTED (`int4`)** |
| **#6** | Phase-Switched Memory Trading (`STRATA_METAL_PHASE_TRADE`: Prefill Scratch <-> Decode Arena) | `stream.cpp`, `window.cpp` | Bitwise identical | Trades `1.12 GB` (`~720` expert slots) between `PromptGemm` and decode LRU (opt-in `PHASE_TRADE=1/2`) | **SHIPPED** |
| **#7** | Paged KV Streaming with Dual-Slot Ring & ROCr Async SDMA Copy Engine | `src/kernels/cuda/kv_stream.cu`, `copy-engine.cu` | Capturable GPU clock-sweep `resolve_kernel` + `copy_kernel` already in Strata | Documented ROCr SDMA engine `1u << (31 - __builtin_clz(mask))` for Desktop RX 7600 XT target | **VERIFIED** |
| **#8** | Prefill-Safe GPU MoE LRU Cache & Coalesced `TENSOR_READ_LAZY` Dense Mmap | `stream.cpp` | `100%` bitwise (`mean_kld = 0.000000`, `GEN_IDS` identical) | Coalesced page-aligned `align_range` + `ranges_complement`: `1,079` syscalls -> `145` lazy + `146` `mlock` spans, never dropping shared 16 KiB boundary pages | **SHIPPED** |
| **#9** | Sub-Warp Column Segmentation in GDN Decode (`gdn_step_t`) | `gdn.metal` | `100%` bitwise (`88/88 PASS` on `plane=0` and `plane=49152`) | **`1.035–1.138x` slower** on M5: strided `(r*128 + j)` state loads lose 32-lane cacheline coalescing | **REJECTED** |
| **#10** | Time-Tiled Sliding-Window GDN Pre-Conv (`gdn_pre_t<TT>`) | `gdn_prompt.metal` | `100%` bitwise (`memcmp == 0` on all 6 buffers, `T=1..2048`) | **`1.004–1.018x` slower** at `T=2048` (`55.0 ms`): L1/L2 already caches `qkv[t-3..t]` at `~95 GB/s` | **REJECTED** |
| **#11** | Zero-Barrier 1-Simdgroup-per-Row `qsa_prep` (`qsa_prep_sg`, `tg = 32` for `ntok >= 3`) | `qsa.metal`, `window.cpp`, `prompt_chain.inc` | `100%` bitwise (`memcmp == 0`) on all 13 QSA buffers (`T=1..2048`, M-RoPE, `qf16`/fp32) | **`0.91–0.97x` (`-3% to -9%`)** at `nt=3..8`, **`0.67x` (`-33%`)** at `nt=64`, **`0.85x` (`-15%`)** at `T=512`, **`0.91–0.92x`** at `T=2048` | **SHIPPED** |
| **#12** | 2D Token-Tiled QSA Indexer Scoring (`qsa_score_t<TT>`) | `qsa.metal` | `100%` bitwise (`memcmp == 0` for `TT = 1, 4, 8`) | **`1.069–1.475x` slower** at decode `nt=1..4` (`pooled` key cache is only 2 MB and stays in M5 SLC/L2) | **REJECTED** |
| **#13** | Logit-Domain / Delayed-Softmax MoE Top-K (`route_topk`, `moe_route`, `router.metal`) | `prompt.metal`, `moe.metal`, `router.metal` | `100%` bitwise `ids` (`0` mismatches across 400 windows), `max\|dw\| <= 5.96e-8` (1 ULP) | **`route_topk` `0.920–0.955x` (`-4.5% to -8.0%`)** across `T=512..2048`; **`moe_route` `0.985–0.994x`** | **SHIPPED** |
| **#14** | Decorrelated Temperature-Synced Draft Sampling (`spec_retune`) | `coupled_draft.hpp`, `spec_prob.hpp` | Exact target distribution $p$ preserved under both coupled & rejection sampling | Strata already implements `STRATA_SPEC_COUPLED=1` (shared Philox draw + Gumbel-max) and `STRATA_SPEC_PROB=1` (disjoint Philox counters `pos \| 1<<61/62/63`) | **VERIFIED** |