Merge pull request 'docs(frank-tts): the engine computes on the gfx1151 now; the NPU question is closed' (#35) from docs/frank-tts-igpu-followup into main

The cutover PR merged the runtime; this carries the surface that has to be
true afterwards.

- Engine page: the shape is now `--device Vulkan0` on the gfx1151 as a
  co-tenant beside frank-dragoon; the registry/thread/streaming laws gain a
  fourth — the device law — whose numbers stay in the verdict report, and the
  deploy record gets the cutover steps including the `glslc` configure gate.
  The CPU-era arm/rollback prose keeps the qualitative argument and drops the
  dead numbers per the purpose test.
- Endpoint page: "Where the engine computes" now says iGPU + co-tenancy, and
  states the NPU verdict in one paragraph instead of a research tour.
- Quadlet comment: it claimed supplementary groups are what grant render
  access. On this host the udev rule world-writes the render nodes and the
  container's `id` shows no groups at all, so keep-groups is belt-and-braces;
  the RSS note now matches the device shape instead of the CPU trial.
- Verdict report: gate 2 (contention) recorded as measured after the cutover,
  and the build-stage prediction corrected — the package is `glslc`, not
  `libvulkan-dev glslang-dev`.
- index.md regenerated (one description changed).

dankclaw/voiceservice/Containerfile.engine

@@ -19,11 +19,14 @@
 # is recorded in the parent tree, so cloning the parent commit recursively is
 # reproducible without a second pin.
 #
-# THE BUILD LINE IS THE ONE PROVEN ON DANKCLAW, verbatim:
+# THE BUILD LINE IS THE ONE PROVEN ON DANKCLAW, verbatim — with the Vulkan door
+# open since 2026-10-19. That configure was run in this exact base image and
+# answers `Found Vulkan: /usr/lib/x86_64-linux-gnu/libvulkan.so (found version
+# "1.3.275") found components: glslc` then `Including Vulkan backend`:
 #
 #   cmake -B build -DCMAKE_BUILD_TYPE=Release -DGGML_CCACHE=OFF \
 #       -DGGML_BACKEND_DL=OFF -DGGML_CPU_ALL_VARIANTS=OFF -DGGML_OPENMP=ON \
-#       -DGGML_BLAS=OFF -DGGML_CUDA=OFF -DGGML_HIP=OFF -DGGML_VULKAN=OFF \
+#       -DGGML_BLAS=OFF -DGGML_CUDA=OFF -DGGML_HIP=OFF -DGGML_VULKAN=ON \
 #       -DGGML_METAL=OFF -DGGML_SYCL=OFF -DGGML_RPC=OFF \
 #   && cmake --build build -j 8
 #
@@ -42,8 +45,12 @@
 #     defaults it ON outside wasm/cross-compiles, i.e. -march=native for THIS
 #     host — correct while build host == run host, wrong if anyone ever builds
 #     this image elsewhere, which is why the fleet builds it on Dankclaw.
-#   CUDA/HIP/VULKAN/METAL/SYCL/RPC all OFF: this is a CPU endpoint (the trial
+#   CUDA/HIP/METAL/SYCL/RPC stay OFF, VULKAN is ON: the endpoint computes on the
-#     ran on CPU; the box's GPUs belong to the text endpoints).
+#     gfx1151 iGPU (decision and co-tenancy gates:
+#     report/tts-npu-spike-verdict-2026-10-19.md, shape in [[Frank TTS Engine]]).
+#     Nothing else is available to this image: no ROCm userland, no NVIDIA
+#     userland, no macOS, no oneAPI, and RPC would add a second process to
+#     supervise on a box that already has one engine per card.
 #
 # BUILD SHARED LIBS, RUNTIME SMALL. BUILD_SHARED_LIBS defaults ON on Linux, so
 # tts-server links libggml*.so rather than swallowing them; the runtime stage
@@ -67,9 +74,28 @@ ARG BASE_IMAGE=docker.io/library/ubuntu:24.04@sha256:68ee22004a9109b44973313b02f
 # ------------------------------------------------------------------ build
 FROM ${BASE_IMAGE} AS build
 
+# The three Vulkan build deps are not optional and not interchangeable:
+#   libvulkan-dev    vulkan/vulkan.h + the VulkanHeaders/VulkanLoader CMake
+#                    configs, i.e. what find_package(Vulkan) resolves to.
+#   glslc            ggml compiles its shaders with glslc, not glslangValidator.
+#                    Ubuntu's glslang-tools ships glslangValidator and NOT glslc,
+#                    so without this package `find_package(Vulkan COMPONENTS
+#                    glslc REQUIRED)` fails and there is no Vulkan backend.
+#                    The archive's glslc is old (2023.8): it compiles
+#                    GL_KHR_cooperative_matrix — the path ggml's quantized
+#                    matmul needs — but reports cooperative_matrix2,
+#                    integer_dot_product, bfloat16 and the micro-float
+#                    extensions as unsupported, so those shader families are
+#                    compiled out. If a Vulkan prefill ever reads as
+#                    inexplicably slow, suspect this compiler before the device;
+#                    the fix is a pinned glslang build passed as
+#                    -DVulkan_GLSLC_EXECUTABLE=<path>, not a different runtime.
+#   spirv-headers    find_package(SPIRV-Headers CONFIG REQUIRED); the distro
+#                    package ships /usr/share/cmake/SPIRV-Headers/.
 RUN apt-get update -qq \
     && apt-get install -y -qq --no-install-recommends \
         ca-certificates cmake g++ git make \
+        libvulkan-dev glslc spirv-headers \
     && rm -rf /var/lib/apt/lists/*
 
 # Checked out detached at a full SHA, then the recorded submodule. No branch
@@ -90,7 +116,7 @@ RUN cmake -B build -DCMAKE_BUILD_TYPE=Release \
         -DGGML_BLAS=OFF \
         -DGGML_CUDA=OFF \
         -DGGML_HIP=OFF \
-        -DGGML_VULKAN=OFF \
+        -DGGML_VULKAN=ON \
         -DGGML_METAL=OFF \
         -DGGML_SYCL=OFF \
         -DGGML_RPC=OFF \
@@ -102,9 +128,21 @@ FROM ${BASE_IMAGE}
 # libgomp1: the OpenMP runtime the build above links against. curl: the unit's
 # HealthCmd. ca-certificates: so that curl can speak https if anyone ever
 # points a probe at a URL with a scheme this host terminates elsewhere.
+#
+# libvulkan1 + mesa-vulkan-drivers are what make `--device Vulkan0` mean
+# anything at runtime: libvulkan1 is the loader libggml-vulkan.so dlopens, and
+# mesa-vulkan-drivers is the RADV ICD that claims the gfx1151. Loader without an
+# ICD enumerates ZERO devices, and tts-server then dies in device lookup AFTER
+# both GGUFs have been read — the journal reads as a model fault, not a missing
+# driver. Enumerated from this base on 2026-10-19 with `--device /dev/dri
+# --group-add keep-groups` plus the host's ComfyUI udev rule: "Radeon 8060S
+# Graphics (RADV GFX1151)", API 1.4.318 (the heap figure is owned by
+# [[Frank TTS Engine]]; it is the GTT-backed aperture, not the ~2 GiB DRM
+# carve-out). No NVIDIA ICD is installed on purpose: one Vulkan device in the
+# enumeration is what makes the NAME Vulkan0 safe to write down.
 RUN apt-get update -qq \
     && apt-get install -y -qq --no-install-recommends \
-        ca-certificates curl libgomp1 \
+        ca-certificates curl libgomp1 libvulkan1 mesa-vulkan-drivers \
     && rm -rf /var/lib/apt/lists/*
 
 # Same unprivileged uid as the frank-tts façade (10000): the voice packs and the

dankclaw/voiceservice/quadlet/frank-tts-engine.container

@@ -40,12 +40,28 @@
 # speaks to the server from inside its own namespace, which is where the address
 # is valid.
 #
-# MEMORY / NO GPU. Peak RSS measured 5.7 GiB with both GGUFs resident
+# MEMORY / THE RENDER NODE. Host RSS is ~1.7 GiB, not the size of the GGUFs:
-# (2026-10-18 trial); no memory limit is set because the box has the room and a
+# the Vulkan backend copies both tensors into device memory at load, so they
-# limit would convert a busy moment into an OOM kill mid-utterance. No
+# stop counting in the process's RSS (measured after the 2026-10-19 cutover —
-# /dev/kfd, no /dev/dri, no keep-groups: every GPU backend is compiled out of
+# `podman stats` / `ps -o rss`). No memory limit is set: the box has the room
-# the image, the endpoint is CPU-only by decision, and the GPUs on this host
+# and a limit would convert a busy moment into an OOM kill mid-utterance.
-# belong to the text endpoints.
+#
+# `AddDevice=/dev/dri` is what makes the iGPU visible; without it the Vulkan
+# ICD enumerates nothing and the server dies on device lookup after it has
+# already read both GGUFs. `GroupAdd=keep-groups` is belt-and-braces, not the
+# thing that works here: the units podman spawns carry no supplementary groups
+# at all, and this host grants render access a different way — the udev rule
+# that makes the render nodes world-writable (same rule ComfyUI rides, see
+# dankclaw/comfyui). Measured: `id` inside this container lists only the
+# container's own group, and `tts-server` still holds renderD129.
+# The node is NOT named: this host is hybrid, renderD128 is the NVIDIA card and
+# renderD129 the amdgpu iGPU, so a node number in the unit is a guess that a
+# re-probe can invalidate, while the directory hands the container every render
+# node and the driver picks by name.
+#
+# /dev/kfd stays absent on purpose: that is the ROCm compute interface, owned by
+# the engines that use HIP. A Vulkan endpoint has no use for it, and handing a
+# container a second way onto the GPU is surface for nothing.
 #
 # THE VOICE MOUNT IS READ-ONLY AND IS FOR THE WARMER, NOT THE ENGINE. A voice
 # becomes known to the engine only through POST /v1/audio/voices, and the
@@ -98,6 +114,9 @@ Network=frank-tts-engine.network
 EnvironmentFile=/home/dank/serverAppConfigs/scripts/frank-tts-engine.env
 Volume=/home/dank/models/Qwen3-TTS-GGUF:/models:ro
 Volume=/home/dank/voices:/voices:ro
+# Render access for the iGPU (see MEMORY / THE RENDER NODE above).
+AddDevice=/dev/dri
+GroupAdd=keep-groups
 HealthCmd=curl -fsS http://127.0.0.1:8880/health
 HealthInterval=30s
 HealthTimeout=10s

dankclaw/voiceservice/tts-engine-start.sh

@@ -7,7 +7,7 @@
 # supervision, no retries, no logging of its own. PID 1 stays the server, so
 # `podman stop` and the unit's Restart=always drive it directly.
 #
-# THE FLAGS THAT ARE NOT HERE, and must stay absent:
+# THE FLAG THAT MUST STAY ABSENT:
 #
 #   --threads / -t   does not exist in this build. src/backend.h computes the
 #                    CPU thread count as std::thread::hardware_concurrency()/2
@@ -18,13 +18,19 @@
 #                    placement — pinning is deliberately not done anywhere in
 #                    this stack. See the env file header for the same warning
 #                    aimed at the operator.
-#   --device         left at its default. Every GPU backend is compiled out of
-#                    the image, so the default device pick can only land on
-#                    CPU; naming a device would add a way to be wrong.
 #
-# Everything defaults to the shape the 2026-10-18 trial measured, so an empty
+# --device IS here, but conditionally: it reaches the binary only when
-# environment still boots the decided configuration: 1.7 B talker Q4_K_M with
+# QWENTTS_DEVICE is non-empty, and empty is the CPU rollback — the binary then
-# the Q8_0 tokenizer, one request at a time, on the private bridge.
+# takes its own default device, which is CPU because the CPU backend is always
+# built. One line in scripts/frank-tts-engine.env moves the endpoint between the
+# two shapes, with no rebuild. What must never reach argv is a device NAME the
+# loader does not enumerate: that is not refused by the argument parser, it dies
+# during device lookup with the loader's own error, so the journal reads as a
+# load that failed rather than a configuration refusal.
+#
+# Everything defaults to the shape this endpoint runs: 1.7 B talker Q4_K_M with
+# the Q8_0 tokenizer, one request at a time, on the private bridge, on the
+# gfx1151 iGPU. An empty environment still boots that shape.
 set -euo pipefail
 
 # The binary path. Overridable for one reason: the bats seam runs a stub
@@ -60,13 +66,33 @@ set -euo pipefail
 : "${QWENTTS_LANG:=auto}"
 
 # One request at a time. The server-side queue is a serialised FIFO at this
-# setting, which is what keeps the measured per-voice timings true; batching
+# setting, which is what keeps the per-voice timings predictable. A second
-# on a CPU build splits the same cores between two syntheses and the warm RTF
+# concurrent synthesis shares the device with the first — and on this box that
-# margin (0.55-0.67 against real time 1.0) disappears. The engine's own
+# device is also carrying frank-dragoon — so it buys no throughput and it
-# default is also 1; it is written here because it is a decision, not an
+# doubles the wait for the caller behind it. The engine's own default is also 1;
-# accident.
+# written here because it is a decision, not an accident.
 : "${QWENTTS_MAX_BATCH:=1}"
 
+# The compute device, NAMED and not numbered: `Vulkan0` is how ggml enumerates
+# the gfx1151 iGPU on this host. An index would follow whatever order the
+# loader's device list returns; a name says which device this endpoint means.
+# The container sees exactly one Vulkan device because the image carries the
+# Mesa ICD and no NVIDIA one, so the 3090 is not in the enumeration at all.
+#
+# EMPTY IS THE CPU ROLLBACK: a value that is set but EMPTY passes no `--device`,
+# the binary picks its own default, and the CPU backend is always built — which
+# is why moving this endpoint between the iGPU and the CPU is one line in
+# scripts/frank-tts-engine.env and not a rebuild.
+#
+# That is also why the default below is NOT `${QWENTTS_DEVICE:=Vulkan0}`: `:=`
+# fires on a set-but-empty variable as well as an unset one, so the rollback line
+# `QWENTTS_DEVICE=` would be rewritten back to Vulkan0 and the endpoint would sit
+# on the shared GPU with no way out short of a rebuild. Only UNSET takes the
+# default.
+if [[ ! -v QWENTTS_DEVICE ]]; then
+    QWENTTS_DEVICE=Vulkan0
+fi
+
 # Fail loudly BEFORE binding, so the journal says which artifact is missing
 # instead of the unit reporting a container that starts and dies. This is the
 # self-healing path: Restart=always re-runs it every RestartSec, and the same
@@ -79,11 +105,20 @@ for artifact in "$QWENTTS_MODEL" "$QWENTTS_CODEC"; do
     fi
 done
 
-exec "$QWENTTS_BIN" \
+ARGS=(
-    --model "$QWENTTS_MODEL" \
+    --model "$QWENTTS_MODEL"
-    --codec "$QWENTTS_CODEC" \
+    --codec "$QWENTTS_CODEC"
-    --alias "$QWENTTS_ALIAS" \
+    --alias "$QWENTTS_ALIAS"
-    --host "$QWENTTS_HOST" \
+    --host "$QWENTTS_HOST"
-    --port "$QWENTTS_PORT" \
+    --port "$QWENTTS_PORT"
-    --lang "$QWENTTS_LANG" \
+    --lang "$QWENTTS_LANG"
     --max-batch "$QWENTTS_MAX_BATCH"
+)
+
+# Only when a device is named. An empty QWENTTS_DEVICE has to produce NO flag,
+# because "the rollback shape" is argv identical to the pre-iGPU endpoint.
+if [[ -n "$QWENTTS_DEVICE" ]]; then
+    ARGS+=(--device "$QWENTTS_DEVICE")
+fi
+
+exec "$QWENTTS_BIN" "${ARGS[@]}"

report/tts-npu-spike-verdict-2026-10-19.md

@@ -136,25 +136,36 @@ TTS engine today|3.84 GiB RSS, CPU|its device-resident replacement lands in that
    ICD**, so Vulkan device 0 is the iGPU here. Do not trust that ordering — select by
    device *name*, or an image that grows an `nvidia_icd.json` silently points TTS at the
    3090 slot.
-2. **Contention gate.** `frank-dragoon` is the endpoint the operator session runs on, so the
+2. **Contention gate — PASSED, measured 2026-10-19 after the cutover.** With a 16.9 s
-   honest measurement with both loaded is dragoon's own TTFT and decode with a synthesis in
+   synthesis occupying the device, `frank-dragoon` answered a streamed 124-token request at
-   flight — one request each, no ladder. Expect compute-unit sharing rather than memory
+   **17 ms to first token and ~35 tok/s decode**, against 17 ms and ~33 tok/s for the same
-   pressure: the aperture has room, the shaders do not.
+   request with the card idle. Compute-unit sharing showed up as nothing. One request per
+   arm, no ladder: these are the gate's evidence, not a throughput record, and the engine's
+   own shape lives in [[Frank TTS Engine]].
 
-**Change surface** — the whole edit, so nobody re-derives it:
+**Change surface — as landed** (PR #34, `6248f02`; the CPU shape stays reachable as the
+rollback):
 
-1. `Containerfile.engine` build stage: add `libvulkan-dev glslang-dev`. It installs only
+1. `Containerfile.engine` build stage: add **`libvulkan-dev glslc spirv-headers`**. The
-   `ca-certificates cmake g++ git make` today, and ggml's Vulkan backend compiles its
+   prediction above (`libvulkan-dev glslang-dev`) is wrong on two counts and the configure
-   shaders at build time — the flag alone fails at configure.
+   says so: ggml looks for `glslc`, which Ubuntu's `glslang-tools` does **not** ship (it
-2. `-DGGML_VULKAN=OFF` → `ON` in the same cmake block; the flag list is written out
+   ships `glslangValidator`), and `find_package(SPIRV-Headers CONFIG REQUIRED)` needs the
-   explicitly, so this is a one-word diff.
+   distro's `spirv-headers`, which does carry the CMake config. `glslc` is its own source
-3. Runtime stage: add `mesa-vulkan-drivers`. Without a Vulkan **ICD inside the image** the
+   package on noble, at 2023.8 — old enough that only `GL_KHR_cooperative_matrix` compiles,
-   device node buys nothing — there is no `radeon_icd.json` in the container today.
+   so the coopmat2 / integer-dot / bf16 / micro-float shader families are built out. Suspect
-4. `frank-tts-engine.container`: `AddDevice=/dev/dri` + `GroupAdd=keep-groups` — **not**
+   that compiler before the device if a Vulkan prefill ever reads as slow.
-   `renderD128`. On this hybrid box that node is the NVIDIA card; the iGPU is
+2. `-DGGML_VULKAN=OFF` → `ON`: one word in the written-out flag list.
-   `renderD129` (`readlink -f /sys/class/drm/renderD129/device/driver` → `amdgpu`).
+3. Runtime stage: `mesa-vulkan-drivers` **and** `libvulkan1` — the ICD and its loader. An
-5. Engine argv: `--device Vulkan0` — qwentts.cpp's tools take `--device <name>` at the
+   image with a loader and no ICD enumerates zero devices.
-   pinned commit.
+4. `frank-tts-engine.container`: `AddDevice=/dev/dri` + `GroupAdd=keep-groups` — the
+   DIRECTORY, never the node: on this hybrid box `renderD128` is the NVIDIA card and
+   `renderD129` the amdgpu iGPU (`readlink -f /sys/class/drm/renderD129/device/driver` →
+   `amdgpu`). On this host the udev rule already makes the nodes world-writable, so the
+   group is belt-and-braces, not the gate.
+5. Engine argv: `--device Vulkan0`, reached through `QWENTTS_DEVICE` in
+   `scripts/frank-tts-engine.env`. **An empty value passes no flag at all** — that is the
+   CPU rollback, and it is why the entrypoint's default is an `-v` test rather than `:=`,
+   which also fires on a set-but-empty value and would silently undo the rollback.
 
 Gate 1 recipe, already run and **PASSED**: `mesa-vulkan-drivers` + `vulkan-tools` in a
 throwaway container off the same base, `--device /dev/dri`, then `vulkaninfo --text` and read

scripts/frank-tts-engine.env

@@ -27,6 +27,16 @@
 # below stop describing the process you are running. Nothing in this fleet
 # pins this container; that is a decision, not an oversight.
 #
+# THE DEVICE LAW (since the 2026-10-19 Vulkan cutover). Synthesis computes on
+# the gfx1151 iGPU — the SAME card frank-dragoon serves. It is a shared device,
+# never a dedicated one, so two numbers matter and neither is what `rocm-smi`
+# prints first: the memory the container may use is the RADV heap inside the
+# GTT-backed aperture (the ~2 GiB DRM carve-out is not the working set), and the
+# timing that matters is dragoon's, measured WITH a synthesis in flight. The
+# rollback is one line: set QWENTTS_DEVICE empty, and the entrypoint passes no
+# --device at all — the pre-iGPU CPU shape, no rebuild, no restart of anything
+# else on the box.
+#
 # THE REGISTRY LAW (why the unit has an ExecStartPost at all). Registrations live
 # in memory only, so a restart loses them, and re-registration alone does NOT warm
 # a voice — the warm pass has to synthesize something. Without it the façade
@@ -103,6 +113,17 @@ QWENTTS_LANG=auto
 # round-trip outside it) is what absorbs the queue.
 QWENTTS_MAX_BATCH=1
 
+# The compute device, by ggml device NAME. `Vulkan0` is the gfx1151 iGPU: the
+# image carries the Mesa (RADV) ICD and no NVIDIA ICD, so this container's
+# Vulkan enumeration has exactly one entry and it is the iGPU. The unit hands
+# the container /dev/dri and keeps the render group; on this hybrid host the
+# iGPU's render node is renderD129 and renderD128 is the NVIDIA card, which is
+# why the unit passes the directory and lets the driver resolve the node.
+#
+# ROLLBACK: an empty value means no --device flag at all — the CPU shape this
+# endpoint shipped with until 2026-10-19. One line, no rebuild.
+QWENTTS_DEVICE=Vulkan0
+
 # --- the boot warmer (dankclaw/voiceservice/tts-engine-warm.sh) --------------
 # These three are read by the warm hook, not by tts-server. They live here
 # because the hook is exec-ed into this container and therefore inherits this

serverAppConfigs-docs/Dankclaw/Frank TTS Engine.md

@@ -1,35 +1,36 @@
 ---
 type: reference
-description: "The engine behind the fleet's speech endpoint: its runtime, private bridge, and the surface it publishes."
+description: "The engine behind the fleet's speech endpoint: its Vulkan build on the iGPU, its private bridge, and what it publishes."
 tags:
   - dankclaw
   - tts
   - voice
   - quadlet
-  - cpu
+  - vulkan
-timestamp: 2026-10-18
+timestamp: 2026-10-19
 ---
 
 # Frank TTS Engine
 
-`frank-tts-engine` is the **arm A text-to-speech engine** on Dankclaw: [qwentts.cpp](https://github.com/ServeurpersoCom/qwentts.cpp)'s resident `tts-server` HTTP process, holding the Qwen3-TTS **1.7 B base talker (Q4_K_M)** and the **12 Hz tokenizer (Q8_0)** in RAM once and synthesizing from there. It listens on container port **8880** and is **deliberately not a fleet endpoint** — the endpoint consumers address is `frank-tts` on **7772**, which resolves voice names, re-encodes to mp3 and owns the timeout budget. This page is the engine runbook; the endpoint's contract lives with its own page.
+`frank-tts-engine` is the **arm A text-to-speech engine** on Dankclaw: [qwentts.cpp](https://github.com/ServeurpersoCom/qwentts.cpp)'s resident `tts-server` HTTP process, holding the Qwen3-TTS **1.7 B base talker (Q4_K_M)** and the **12 Hz tokenizer (Q8_0)** loaded once and synthesizing from there — **on the gfx1151 iGPU** (ggml's Vulkan backend, `--device Vulkan0`) since 2026-10-19, and in host RAM before that. It listens on container port **8880** and is **deliberately not a fleet endpoint** — the endpoint consumers address is `frank-tts` on **7772**, which resolves voice names, re-encodes to mp3 when asked, and owns the timeout budget. This page is the engine runbook; the endpoint's contract lives with its own page.
 
-**Deployed 2026-10-18.** The chain ran in the order at the bottom of this page — fetch (1.4 GiB, byte + LFS oid verified, 18 s), image build against the pinned commit, unit + network install, container-health gate, warm pass — and the live state still reads the way this page describes it: unit `active` with no drop-ins, container healthy 31 s after the build, **4.0 GiB** resident on a host that kept 17 GiB available, `3 voice(s) registered and warm` in the journal, and no published port anywhere. Two things the first real boot taught: the warm hook's registration body must reach curl through a **file**, not an argument (Troubleshooting), and `STEP 3/13 RUN useradd` is the first honest proof of the image's non-root user.
+**Deployed 2026-10-18, cut over to the iGPU on 2026-10-19.** The first chain ran in the order at the bottom of this page — fetch (1.4 GiB, byte + LFS oid verified), image build against the pinned commit, unit + network install, container-health gate, warm pass — and the live state still reads the way this page describes it: unit `active` with no drop-ins, container healthy shortly after the build, `3 voice(s) registered and warm` in the journal, and no published port anywhere. Two things the first real boot taught: the warm hook's registration body must reach curl through a **file**, not an argument (Troubleshooting), and `STEP 3/13 RUN useradd` is the first honest proof of the image's non-root user.
 
 **Host:** Dankclaw (`192.168.0.143`), rootless Podman, user `dank` — **Port:** 8880, **never published** — **Network:** the private `systemd-frank-tts-engine` bridge (10.89.5.0/24) and no other — **Deployer:** `frank-tts-engine` — **Consumers:** `frank-tts` (7772) and, through it, every voice request in the fleet including [[Open Notebook]]'s podcast renders.
 
-## Facts (verified 2026-10-18 against the pinned upstream commit, the Hub, and the CPU trial on this host)
+## Facts (verified 2026-10-18 against the pinned upstream commit, the Hub and the CPU trial; the device rows re-verified on the live iGPU shape 2026-10-19)
 
 | Item | Value |
 |------|-------|
 | Engine | `tts-server` from qwentts.cpp, pinned at commit `5916bf7c79dbb4e66fc059cdc507a79a23a28bb4` (`dankclaw/voiceservice/Containerfile.engine`). The source is **not vendored**: the image clones that commit and its recorded `ggml` submodule, so the build needs outbound HTTPS and the `cfhash` label is what keeps an unchanged re-deploy offline |
-| Build line | `cmake -B build -DCMAKE_BUILD_TYPE=Release -DGGML_CCACHE=OFF -DGGML_BACKEND_DL=OFF -DGGML_CPU_ALL_VARIANTS=OFF -DGGML_OPENMP=ON -DGGML_BLAS=OFF -DGGML_CUDA=OFF -DGGML_HIP=OFF -DGGML_VULKAN=OFF -DGGML_METAL=OFF -DGGML_SYCL=OFF -DGGML_RPC=OFF && cmake --build build -j 8` — the exact line the 2026-10-18 trial ran on this box. `GGML_BLAS=OFF` is **forced**: Dankclaw has `libopenblas.so.0` and no BLAS dev headers, so upstream's own `Dockerfile` and `buildcpu.sh` (both of which pass BLAS on) cannot be copied. No `-DGGML_NATIVE` is passed, and ggml defaults it on, so the binary is `-march=native` for the machine that built it: **build this image on the host that runs it** |
+| Build line | `cmake -B build -DCMAKE_BUILD_TYPE=Release -DGGML_CCACHE=OFF -DGGML_BACKEND_DL=OFF -DGGML_CPU_ALL_VARIANTS=OFF -DGGML_OPENMP=ON -DGGML_BLAS=OFF -DGGML_CUDA=OFF -DGGML_HIP=OFF -DGGML_VULKAN=ON -DGGML_METAL=OFF -DGGML_SYCL=OFF -DGGML_RPC=OFF && cmake --build build -j 8`. **`GGML_VULKAN=ON` since 2026-10-19**, and that door needs three packages in the build stage: `libvulkan-dev`, `spirv-headers`, and **`glslc`** — which Ubuntu's `glslang-tools` does NOT ship (it ships `glslangValidator`, and `find_package(Vulkan COMPONENTS glslc REQUIRED)` fails without the package). The archive's `glslc` is 2023.8: `GL_KHR_cooperative_matrix` compiles, the coopmat2 / integer-dot / bf16 / micro-float shader families do not. `GGML_BLAS=OFF` is **forced**: Dankclaw has `libopenblas.so.0` and no BLAS dev headers, so upstream's own `Dockerfile` and `buildcpu.sh` (both pass BLAS on) cannot be copied. No `-DGGML_NATIVE` is passed, and ggml defaults it on, so the binary is `-march=native` for the machine that built it: **build this image on the host that runs it** |
-| Image | built locally as `franksdank/frank-tts-engine:latest`, two stages from one digest-pinned base `docker.io/library/ubuntu:24.04@sha256:68ee22004a9109b44973313b02ff7b1de250f1de0f5ecb628d73f579aaff33ac` (index digest resolved 2026-10-18). Runtime stage: `libgomp1` (OpenMP is on), `curl` (the unit's `HealthCmd` runs as `/bin/sh -c`, and the warmer speaks HTTP), uid **10000**, `LD_LIBRARY_PATH=/app` because ggml builds shared by default and the link-time RPATH names the build tree |
+| Image | built locally as `franksdank/frank-tts-engine:latest`, two stages from one digest-pinned base `docker.io/library/ubuntu:24.04@sha256:68ee22004a9109b44973313b02ff7b1de250f1de0f5ecb628d73f579aaff33ac` (index digest resolved 2026-10-18). Runtime stage: `libgomp1` (OpenMP is on), `curl` (the unit's `HealthCmd` runs as `/bin/sh -c`, and the warmer speaks HTTP), `libvulkan1` + `mesa-vulkan-drivers` (the loader and the RADV ICD — a loader with no ICD enumerates ZERO devices, and the server then dies in device lookup after both GGUFs have been read), uid **10000**, `LD_LIBRARY_PATH=/app` because ggml builds shared by default and the link-time RPATH names the build tree. **No NVIDIA ICD on purpose**: exactly one Vulkan device in the enumeration is what makes the name `Vulkan0` safe to write down |
 | Talker | `qwen-talker-1.7b-base-Q4_K_M.gguf`, **1 219 245 248 B**, sha256 `ea393ebaf2167ea23ce9fc18b093822851358a950d7075cd47ab4f6ce23e887d` (the Hub's LFS pointer oid) |
 | Tokenizer | `qwen-tokenizer-12hz-Q8_0.gguf`, **291 150 624 B**, sha256 `1883beeed99348fc35e23dd225e9082f93f6f8c109330a33d935baa8acdbfd94` |
 | Source of both | `https://huggingface.co/Serveurperso/Qwen3-TTS-GGUF`, fetched by `scripts/download-frank-tts-engine-qwentts.sh` into `/home/dank/models/Qwen3-TTS-GGUF`, mounted read-only at `/models`. It has to be the **base** variant: the engine refuses every voice registration unless the model reports type `base`, so on `customvoice`/`voicedesign` the cloned-voice product does not exist. A 0.6 B talker (628 905 056 B) exists and is **not** the decided artifact |
-| Memory | **5.7 GiB peak RSS** with both files resident (2026-10-18 trial). No `LimitMEMORY`/`MemoryMax`: a limit would turn a busy moment into an OOM kill in the middle of an utterance |
+| Device | `--device Vulkan0`: the gfx1151 iGPU, **shared with [[frank-dragoon]] as a co-tenant, never a handover**. Proven on the live pair, not inferred: `fuser -v /dev/dri/renderD129` lists `tts-server` beside `flash_serve`. Both gates (the RADV heap and dragoon's contention) are §5 of `report/tts-npu-spike-verdict-2026-10-19.md`, which also carries the change surface. **Rollback: `QWENTTS_DEVICE=` (empty) in `scripts/frank-tts-engine.env`, redeploy this one service** — the entrypoint then passes no `--device` at all, which is the CPU shape, no rebuild, nothing else restarts |
-| Concurrency | `--max-batch 1`: a serialised FIFO. Warm RTF on this box is 0.55–0.67 against real time 1.0, and that margin is the entire headroom a live stream has; two concurrent syntheses split the same cores and the second caller's first byte additionally waits for the first utterance to finish |
+| Memory | **1.7 GiB host RSS** since the iGPU cutover — the weights ride the device. No `LimitMEMORY`/`MemoryMax`: a limit would turn a busy moment into an OOM kill in the middle of an utterance |
+| Concurrency | `--max-batch 1`: a serialised FIFO. Warm RTF on the iGPU measures **0.20** (11.04 s of audio in 2.23 s) with `frank-dragoon` live on the same card, so a live stream has room to spare; a second concurrent synthesis would share the device with the first and make the caller behind it wait out the whole first utterance, so the FIFO stays a decision, not an accident |
 | Network | `systemd-frank-tts-engine` (10.89.5.0/24, `dankclaw/voiceservice/quadlet/frank-tts-engine.network`) and **nothing else**, with **no `PublishPort` at all**. `frank-tts` joins the same bridge and dials `http://frank-tts-engine:8880` |
 | Voices | `/home/dank/voices` mounted read-only at `/voices`, and it is the **warmer** that reads it, not the server: `tts-server` receives reference audio as base64 in a registration body and keeps its registry in memory only |
 | Health | `GET /health` → `{"status":"ok"}`, served by the HTTP thread rather than the synthesis queue, so a busy engine still reads healthy. Probed by the unit (`HealthCmd`, 30 s interval, 120 s start period) **inside the container's namespace**, because there is no published port to probe from outside |
@@ -37,18 +38,11 @@ timestamp: 2026-10-18
 
 ## Why this engine, and not the alternatives
 
-The criterion Frank set on 2026-10-18 was **"whatever is better for live output"**, and live output is decided by time-to-first-audio and by whether the stream stays ahead of real time — not by benchmark throughput. RTF only has to stay under 1.0 with margin; what separates the arms is first-byte latency and **spread**. Measured on this host the same day (CPU; the full A/B is the section *"Decision: arm A for live output (2026-10-18)"* in , which is the source of these numbers):
+The criterion Frank set on 2026-10-18 was **"whatever is better for live output"**, and live output is decided by time-to-first-audio and by whether the stream stays ahead of real time — not by benchmark throughput. On that criterion the resident `tts-server` (arm A) beat the mainline per-request CLI path (arm B) on this box the same day, and the deciding property was **spread**: the resident server repeats the same first-audio latency every run, while the CLI path varies enough that some runs fall behind real time and a live listener hears the stream stall mid-sentence. That A/B was a CPU measurement and the endpoint has since moved to the iGPU, so the shape of the argument is what is kept here; no page carries its numbers any more, and they are not worth re-deriving.
 
-| Measure | Resident `tts-server` (arm A, chosen) | Mainline per-request CLI path (arm B) |
+The rollback to the other backend stays in the repo untouched — `TTS_BACKEND=llama-tts-cli` in `scripts/frank-tts.env` still selects the per-request CLI engine, and that file's header documents what it costs.
-|---|---|---|
-| first audio byte | **86–451 ms** end to end; **94–112 ms** server-side | model load, per request |
-| warm real-time factor while streaming | **0.55–0.67** | 0.93–0.99 |
-| run-to-run spread | **±0.01** | ±0.25 |
-| HTTP surface | serves `/v1/audio/speech` itself | none — façade CLI only |
 
-The spread is the whole argument: at ±0.01 the engine finishes synthesizing 1.5–1.8× faster than the audio plays, every run; at ±0.25 some runs fall behind real time and a live listener hears the stream stall mid-sentence. The rollback path stays in the repo untouched — `TTS_BACKEND=llama-tts-cli` in `scripts/frank-tts.env` still selects the per-request CLI engine, and that file's header documents what it costs.
+## Four laws this service lives under
-
-## Three laws this service lives under
 
 **1. The registry law → the unit warms at boot.** The voice registry is **memory only**: a restart forgets every voice, and re-registering one does **not** warm it — only synthesizing does. A boot that registers nothing leaves the façade answering 400 for every name, which is why `frank-tts-engine.container` carries
 
@@ -64,10 +58,12 @@ frank-tts-engine-warm: voice narrator1 cold=1402ms warm=1812ms
 frank-tts-engine-warm: 3 voice(s) registered and warm
 ```
 
-**2. The thread law → nothing is ever pinned.** `tts-server` in this build has **no `-t`/`--threads` flag**: `src/backend.h` computes the CPU thread count as `std::thread::hardware_concurrency() / 2` (its comment: GEMM shares SIMD units across hyperthreads). Thread count therefore follows what the kernel *reports*, not what a cgroup *allows* — so `CPUQuota=`, `CPUAffinity=`, `taskset` or a slice silently changes the engine's GEMM tiling and its timings, with no log line. Nothing in this fleet pins this container. If a neighbour starves it, fix the neighbour.
+**2. The thread law → nothing is ever pinned.** `tts-server` in this build has **no `-t`/`--threads` flag**: `src/backend.h` computes the CPU thread count as `std::thread::hardware_concurrency() / 2` (its comment: GEMM shares SIMD units across hyperthreads). Thread count therefore follows what the kernel *reports*, not what a cgroup *allows* — so `CPUQuota=`, `CPUAffinity=`, `taskset` or a slice silently changes the engine's pool sizes and its timings, with no log line. The rule did not retire with the iGPU cutover: the binary still sizes those pools from what the kernel says, whatever the device ends up doing with the matmuls. Nothing in this fleet pins this container. If a neighbour starves it, fix the neighbour.
 
 **3. Streaming is not buffered.** At the same seed, `response_format=pcm` (chunked, codec chunks pushed as they decode) and `response_format=wav` (buffered) differ in **92.2 % of samples**, −41.6 dB RMS. Nothing may compare the two paths, cache one against the other, or assume a seed pins output across `response_format`. `frank-tts` always asks for `wav`; the warmer asks for `wav`; the test seam is forbidden from pinning either.
 
+**4. The device law → the card is shared, and the rollback is one line.** Synthesis computes on the gfx1151 **beside** [[frank-dragoon]], so a change to either tenant is a change to both. Two gates decide that pair, and both passed on 2026-10-19 with the other tenant live: the RADV heap a rootless container tenant is actually handed (not the ~2 GiB DRM carve-out), and dragoon's own first-token and decode rates with a synthesis in flight — unchanged. Their numbers, the recipe that measures them, and the full change surface are §5 of `report/tts-npu-spike-verdict-2026-10-19.md`; do not re-derive them here. What belongs on this page is the move: `QWENTTS_DEVICE=` (empty) in `scripts/frank-tts-engine.env`, re-deploy this one service, and synthesis is back on CPU — no rebuild, and dragoon never restarts.
+
 ## The voice registry contract
 
 A voice becomes known to the engine through `POST /v1/audio/voices`, and only these shapes are accepted:
@@ -97,9 +93,9 @@ The **façade** on 7772 is the pair's public surface and carries the probe. Note
 | `dankclaw/voiceservice/Containerfile.engine` | two-stage build of the pinned commit, proven cmake line, digest-pinned base, ships both scripts |
 | `dankclaw/voiceservice/tts-engine-start.sh` | image entrypoint (`/app/start.sh`): env → flags, refuses to boot without weights |
 | `dankclaw/voiceservice/tts-engine-warm.sh` | boot warmer (`/app/warm-voices.sh`): register from `reference.wav` (body via a temp file), speak a fixed sentence twice, report cold/warm |
-| `dankclaw/voiceservice/quadlet/frank-tts-engine.container` | the unit: bridge only, no publish, env file, two read-only mounts, health probe, warm hook, `Restart=always` |
+| `dankclaw/voiceservice/quadlet/frank-tts-engine.container` | the unit: bridge only, no publish, env file, two read-only mounts, render access (`AddDevice=/dev/dri` + `GroupAdd=keep-groups`), health probe, warm hook, `Restart=always` |
 | `dankclaw/voiceservice/quadlet/frank-tts-engine.network` | the private 10.89.5.0/24 bridge, with the subnet registry |
-| `scripts/frank-tts-engine.env` | paths and numbers only, with the thread law and the registry law in its header |
+| `scripts/frank-tts-engine.env` | paths and numbers only, with the thread law, the registry law and the device law in its header |
 | `scripts/download-frank-tts-engine-qwentts.sh` | weight fetcher: no resume, byte count + LFS oid check, `--verify-only` |
 | `scripts/deploy-remote.sh` → `deploy_frank_tts_engine` | weights gate → build → quadlet → restart → container health → warm |
 | `tests/frank_tts_engine.bats` | the seam: generator output, entrypoint argv, warmer against a stub engine, planner and routing maps |
@@ -118,6 +114,25 @@ still open.
 6. **Then the façade on 7772** (its own page), after the engine answered — that order is the whole point of step 6: publishing the façade in front of a dead engine would make every consumer fail at the first voice line.
 7. **Open:** [[Open Notebook]] is still not installed, so nothing renders a podcast yet; the voice leg it waits on now exists.
 
+### 2026-10-19 — the iGPU cutover (PR #34, `6248f02`)
+
+1. **Configure gate before touching anything** — the flag set, configured inside the
+   digest-pinned base on Dankclaw: `Found Vulkan: … found components: glslc` then
+   `Including Vulkan backend`. That probe is what caught `glslc` missing from
+   `glslang-tools`; the Containerfile's flag comment carries the finding.
+2. **Deploy** — `./scripts/deploy.sh dankclaw --service frank-tts-engine`: image rebuild
+   (the `cfhash` moved), unit reinstall, health gate, warm pass
+   (`3 voice(s) registered and warm`), Playwright e2e 33/33.
+3. **Prove the device, not the flag** — `sudo fuser -v /dev/dri/renderD129` lists
+   `tts-server` next to dragoon's `flash_serve`. Do this instead of reading the log: the
+   engine prints nothing about which backend it chose, so argv (`--device Vulkan0`) proves
+   intent and the render-node holder list proves use.
+4. **Consumer path** — one `/v1/audio/speech` per voice through the façade on 7772; all
+   three answered with audio. The RTF figure in the Facts table comes from one engine-direct
+   WAV, where the duration is exact.
+5. **Co-tenancy gate** — §5 of the verdict report: dragoon's first token and decode
+   unchanged with a 16.9 s synthesis occupying the card.
+
 ## Troubleshooting
 
 | Symptom | Meaning | Move |
@@ -131,3 +146,5 @@ still open.
 | `podman exec` in the deploy says `no such file or directory` for `/app/warm-voices.sh` | the image predates the warmer | re-deploy: since 2026-10-18 `build_compose_image` hashes every file the image `COPY`s, not only `Containerfile.engine`, so editing the warmer rebuilds it — see  |
 | The warm pass logs `registered, but the warm synthesis failed` for EVERY voice, while a hand-run `/app/warm-voices.sh` succeeds | `WARM_TEXT` arrived **with its quotes**. podman's `--env-file` does no shell parsing — it takes the literal remainder of the line — so the env-file reader got `"Warm up, one two three."` where `source` gives `Warm up, one two three.`; the quotes plus a backslash then make the synthesis body invalid JSON | the hook strips one matched pair and escapes what is left; prove the value with `podman exec frank-tts-engine env \| grep WARM_TEXT`. The seam pins both readers, because a test that only sources the env file cannot see this |
 | A `502` for `/v1/voices` where the engine answers `200` on `/health` from the same boot | the engine restarted and its in-memory registry is empty again — `/health` is model-loaded, NOT voices-registered | re-run `podman exec frank-tts-engine /app/warm-voices.sh`; that is the same distinction the `frank-tts` healthcheck enforces |
+| Unit restarts every 10 s and the log ends on a **device** error *after* both GGUFs were read | the image has the Vulkan loader but no ICD, or the container has no render node — the device name then resolves to nothing | `podman exec frank-tts-engine ls /dev/dri` (it must see `renderD129`) and `podman exec frank-tts-engine dpkg -l \| grep -E 'mesa-vulkan\|libvulkan1'`; re-deploy to rebuild the image, or set `QWENTTS_DEVICE=` and re-deploy for the CPU shape |
+| `frank-dragoon` slows while TTS speaks | the contention premise broke — a Mesa bump, a third GPU tenant, a bigger synthesis | `QWENTTS_DEVICE=` + re-deploy this service, then re-run the gate recipe in §5 of `report/tts-npu-spike-verdict-2026-10-19.md` before putting it back |

serverAppConfigs-docs/Dankclaw/Frank TTS.md

@@ -113,17 +113,18 @@ shows up as a failed synthesis, never as a down probe.
 
 ## Where the engine computes
 
-CPU, and only CPU is compiled in: `Containerfile.engine` builds `qwentts.cpp` with
+The **gfx1151 iGPU**, as a co-tenant beside `frank-dragoon`: the Vulkan build of
-`-DGGML_VULKAN=OFF` written out explicitly, so the container carries `libggml-cpu` and no
+`qwentts.cpp` with `--device Vulkan0`, and `/dev/dri` handed to the engine container. That is
-other backend. The realistic accelerator is the gfx1151 iGPU behind that flag — plus
+the shape since 2026-10-19. The flag, the device name, the render-node trap on this hybrid box
-`/dev/dri` passthrough, the ComfyUI pattern — on the same payload and the same pinned
+and the one-line CPU rollback are owned by [[Frank TTS Engine]] — read that page before
-commit, and the intended shape is **co-tenancy**: the engine resident on the card beside
+touching either tenant, because a change to one is a change to both. Co-tenancy was gated with
-`frank-dragoon`, not a handover. Memory is not what decides that; shader contention is, and
+`frank-dragoon` live on the card (its first token and decode rates unchanged with a synthesis
-the census plus both gates are in `report/tts-npu-spike-verdict-2026-10-19.md` §5.
+in flight); both gate recipes are §5 of `report/tts-npu-spike-verdict-2026-10-19.md`.
-**The Strix Halo NPU is not a door at all**: XDNA2 executes only precompiled AIE
+
-partition programs, and AMD's own Linux runtime opens `/dev/accel/accel0`, succeeds at the
+**The Strix Halo NPU is not a door at all**: XDNA2 executes only precompiled AIE partition
-ioctls, then declines this model family's graph without emitting a single log line. The
+programs, and AMD's own Linux runtime opens `/dev/accel/accel0`, succeeds at the ioctls, then
-measured record and the model-side contract live in `report/` at the repo root
+declines this model family's graph without emitting a single log line. The measured record and
+the model-side contract live in `report/` at the repo root
 (`tts-npu-spike-verdict-2026-10-19.md`).
 
 ## Files

serverAppConfigs-docs/LLM/LLM Performance Diagnosis.md

@@ -1,9 +1,9 @@
 ---
 type: reference
 title: LLM Performance Diagnosis
-description: "Probing why a served model is slow: the flat-depth probe, offload duty-cycle arithmetic, and profiler attribution."
+description: "Probing why a served model is slow: the flat-depth probe, offload duty-cycle arithmetic, and step-shape attribution."
 tags: [performance, profiling, moe, pcie, prefix-cache, routing, telemetry]
-timestamp: 2026-10-05T00:00:00-07:00
+timestamp: 2026-10-19T00:00:00-07:00
 ---
 
 # LLM Performance Diagnosis
@@ -213,9 +213,75 @@ function directly with synthetic bodies (stdlib-only policy module)
 conversation identity is the FIRST N KiB of prompt — a shorter tested prefix
 hashes differently per turn and pinning silently never happens.
 
+## 9. Decode cadence under a prefill (the step-shape census)
+
+"Decode turns to sludge the moment a long prompt arrives, then recovers" is not a
+link or a gather story — on a chunked-prefill engine the unit of interference is
+**the step**. A step that carries a prefill chunk takes the chunk's time, and every
+decode row sharing that step waits that long for its next token. Chunk size is
+`min(remaining, --checkpoint-interval, --max-num-batched-tokens)`, so on a hybrid
+model the interval caps it before the budget does.
+
+Census it without touching the model — the engine's own counters (`/stats`,
+`/metrics`, cumulative since boot):
+
+```
+decode-only step = step_ns_decode / steps_decode
+shared step      = (step_ns - step_ns_decode) / (steps_prefill + steps_mixed)
+```
+
+Then bucket a day of `decode_tokens_per_second` by `prefill_tokens_per_second`
+(Prometheus `query_range`, step 120 s) and **check the lag**: correlate decode with
+prefill at lag 0 and again at 2-14 minutes. Lag-0-only ⇒ step-time contention, the
+chunk is holding the device. A lagged tail ⇒ residency churn — the prefill's working
+set evicted something decode needs (expert slab, KV) and decode pays after the
+prefill is over. `preemptions` separates the third shape: a preempted-and-recomputed
+sequence stops producing entirely and then re-prefills from token 0, which is a
+stall, not sludge.
+
+Knobs, in the order worth trying them (radiance GUIDE §4.5):
+
+- `--prefill-interleave N` — after a chunk step taken beside decoders, the next N
+  steps carry decode rows only and admit nothing. Decoders keep their cadence; the
+  prompt pays that in TTFT. Counts as `engine_steps_held_total`.
+- `--busy-prefill-chunk MODE` — the chunk's share of a step that has other work:
+  `auto` (default) reserves a row plus the draft window per decode row behind it and
+  an eighth of the budget per waiting prefill/request, `off` lets the chunk take the
+  whole step (admission never runs while it does), `N` pins the share. Never under
+  the prefill stager's smallest pass — the startup line names it, and below it every
+  routed layer reads its pooled experts synchronously, which costs the prefill far
+  more than sharing saves. Counts as `engine_prefill_chunks_capped_total`.
+- `--max-num-batched-tokens` — the blunt rung, and the only one older pins have. The
+  vendor's curve on a 48-layer MoE at 200k on two cards: chunk 512 → 1750 t/s, 1024
+  → 2200, 2048 → 2706 (a 185k prompt: 138 s against 91 s), so halving the stall
+  costs ~19 % of prefill. Raising it past the interval buys nothing and loses expert
+  residency to the arena.
+- `--prefill-span N` — the inverse trade: a *lone* prefill carries N intervals a step
+  while every shared step is planned at a smaller shared budget, which on an
+  expert-tiered box lends that arena back to the expert slab. Vendor TP2
+  expert-tiered TTFT deltas vs a plain 2048 budget: −6.1 % at 2k, +2.3 % at 18k,
+  +49.1 % at 250k — long prompts only.
+
+Two traps. **The arena/slab coupling makes a shared step doubly expensive on an
+expert-tiered shape**: the full-plan arena takes VRAM the resident expert slab would
+have had (320 MiB/card at TP2 for a 4096 budget), so the decode rows inside that step
+also read experts over the link — a smaller shared budget helps twice. And **re-check
+`prefix_hit_rate` / `prefix_evictions` after any chunk change**: the arena and the KV
+pool are the same memory, and the failure looks like turn two taking as long as turn
+one.
+
+Availability is a version question, not a config question: `--busy-prefill-chunk` and
+`--prefill-interleave` are absent from older pins — prove it on the running container
+(`podman exec <c> <binary> --help | grep -iE "prefill|chunk"`), never from the vendored
+tree, and check the source clone's depth before dating a flag from `git log -S`
+(a `--depth 1` clone reports its own tip for every search).
+
+Run on: [[frank-archon]] (radiance 1.0.13, TP2 `expert_tiered`, budget 2048 = interval
+2048) — the measured census and the verdict for this fleet's shape are that page's.
+
 ## Related
 
 -  the window discipline and usage-counter law
 - [[PCIe Link and Atomics]] — link probing and the streaming-vs-compute ceiling
 - [[RDNA4 MoE Expert Offload VRAM Budget]] — the plan behind duty-cycle terms
--  the compile fix for the pointwise-glue bound
+- [[frank-archon]] — the endpoint where §9's step-shape census was run

serverAppConfigs-docs/LLM/frank-archon.md

@@ -239,6 +239,29 @@ vllm-radiance era (this table opens on 09-26; the era page claims 10-10).
 - **MNBT 2048.** 2560 collapses decode to 2.6-7.7 t/s (MTP resonance); the w4 file tier streams
   in place only at MNBT ≤ 2048 and the activation arena scales with the chunk (32768 → 33.3
   GiB, refused).
+- **Decode pays for the chunk it shares a step with.** Census of the live engine
+  (radiance 1.0.13, `/stats` + `/metrics`, cumulative over the 2026-10-15 boot):
+  1,435,585 decode-only steps at **18.7 ms** each against 127,991 prefill+mixed steps
+  at **317 ms** — 60 % of engine wall-clock spent inside 8 % of the steps, because the
+  chunk is `min(remaining, checkpoint interval 2048, MNBT 2048)` = 2048 rows and every
+  decode row in that step waits the whole chunk. Day of Prometheus (120 s step, 721
+  samples): `decode_tokens_per_second` median **13.3 t/s** in the 56 % of samples where
+  `prefill_tokens_per_second` ≥ 1000, against 106-240 t/s in the light-prefill buckets;
+  bucketed by mean step time it is 128.7 t/s at 0.02-0.05 s steps and 12.0 t/s at
+  0.15-0.4 s. The stall is **during**, not after — decode in windows 2-14 min after a
+  busy-prefill window sits at the idle baseline (58-64 vs 77-85 t/s, the residual
+  confounded by co-scheduling), so no lingering expert-residency penalty at 2-minute
+  resolution, and `preemptions: 0` rules out preempt-and-re-prefill. Method:
+  [[LLM Performance Diagnosis]] §9.
+- **The knobs for it are not in this pin.** `--busy-prefill-chunk` and
+  `--prefill-interleave` (radiance GUIDE §4.5 — a shared chunk's cap, and N decode-only
+  steps after each chunk) are absent from 1.0.13: proven on the running container
+  (`podman exec frank-archon radiance --help` prints no `prefill`/`chunk` flag), and the
+  2026-10-18 source tree carries both. The only crank this pin has is MNBT, and that is
+  an arm and not an edit: the vendor prices a 1024 chunk at −19 % prefill to halve the
+  stall, and this page's own MNBT law already knows 2560 collapses decode (MTP
+  resonance). An image bump is gated by the 1.2.0 numerics dead end below, so any try
+  re-scores draft acceptance before it is trusted.
 - **Slots cost KV and rows, never speed.** `--max-num-seqs` carries no radiance constraint: it
   adds 110 MiB of recurrent state per slot and declares the fused TP all-reduce over `seqs ×
   (1 + spec)` rows, and `wht6` is bit-exact up to 25 rows (single-sequence decode and any step

serverAppConfigs-docs/LLM/index.md

@@ -35,7 +35,7 @@ the endpoint's **Eras** table, and the numbers a retired era measured are gone.
 | [[GGUF Compatibility]] | Answering whether an engine loads a GGUF from the file header alone, and pinning a fork build that can. |
 | [[Heterogeneous Split Triage]] | Triage before splitting across unequal accelerators: link characterisation, real bottleneck, what placement never buys. |
 | [[Llama Cpp Serving Sizing]] | Measurement-first sizing for llama.cpp shapes: slot pools against a headroom band, per-device accounting, prompt cache. |
-| [[LLM Performance Diagnosis]] | Probing why a served model is slow: the flat-depth probe, offload duty-cycle arithmetic, and profiler attribution. |
+| [[LLM Performance Diagnosis]] |  Probing why a served model is slow: the flat-depth probe, offload duty-cycle arithmetic, and step-shape attribution. |
 | [[Model Swap and Rollback]] | The model-swap discipline: fit preflight, fetch verification, build and flag checks, live validation, three-pin revert. |
 | [[PCIe Link and Atomics]] | Link probing, the streaming-versus-compute ceiling arithmetic, and the atomics wall that decides multi-GPU collectives. |
 | [[Quantization by Hardware Architecture]] | This page maps LLM quantization formats to the GPU and CPU architectures that support them. |

serverAppConfigs-docs/index.md

@@ -23,7 +23,7 @@ is a locator: one row, one clause, no numbers.
 | [[ComfyUI Qwen-Image Workflows]] | Proven Qwen-Image text-to-image workflows on Dankclaw: the recipes, the API call shape, and which models to add next. |
 | [[Dankclaw Stack]] | Service inventory and routing overview for the Dankclaw AI, development, and observability host. |
 | [[Frank TTS]] | The fleet's cloned-voice speech endpoint and the one voice surface consumers address; wired as the harness speech role. |
-| [[Frank TTS Engine]] | The engine behind the fleet's speech endpoint: its runtime, private bridge, and the surface it publishes. |
+| [[Frank TTS Engine]] | The engine behind the fleet's speech endpoint: its Vulkan build on the iGPU, its private bridge, and what it publishes. |
 | [[Gitea]] | Gitea deployment on Dankclaw with its web UI reverse-proxied by the canonical Caddy service. |
 | [[Gluetun]] | Gluetun is a lightweight VPN client container. |
 | [[Hermes]] | Hermes is the self-improving AI agent from Nous Research. |
@@ -154,7 +154,7 @@ is a locator: one row, one clause, no numbers.
 | [[GGUF Compatibility]] | Answering whether an engine loads a GGUF from the file header alone, and pinning a fork build that can. |
 | [[Heterogeneous Split Triage]] | Triage before splitting across unequal accelerators: link characterisation, real bottleneck, what placement never buys. |
 | [[Llama Cpp Serving Sizing]] | Measurement-first sizing for llama.cpp shapes: slot pools against a headroom band, per-device accounting, prompt cache. |
-| [[LLM Performance Diagnosis]] | Probing why a served model is slow: the flat-depth probe, offload duty-cycle arithmetic, and profiler attribution. |
+| [[LLM Performance Diagnosis]] | Probing why a served model is slow: the flat-depth probe, offload duty-cycle arithmetic, and step-shape attribution. |
 | [[Model Swap and Rollback]] | The model-swap discipline: fit preflight, fetch verification, build and flag checks, live validation, three-pin revert. |
 | [[PCIe Link and Atomics]] | Link probing, the streaming-versus-compute ceiling arithmetic, and the atomics wall that decides multi-GPU collectives. |
 | [[Quantization by Hardware Architecture]] | This page maps LLM quantization formats to the GPU and CPU architectures that support them. |

tests/frank_tts_engine.bats

@@ -331,13 +331,40 @@ FAKE
     [ "$(argv --port)" = "8880" ]
     [ "$(argv --lang)" = "auto" ]
     [ "$(argv --max-batch)" = "1" ]
-    # The two flags that must never appear: there is no thread count to set (it
+    # The device the env names has to reach argv BY NAME: the image ships the
-    # comes from hardware_concurrency()/2), and naming a device on an image with
+    # Mesa ICD and no NVIDIA one, so Vulkan0 is the gfx1151 and cannot drift onto
-    # every GPU backend compiled out is only a new way to be wrong.
+    # another card the way an index would.
-    ! grep -qx -- '--device' "$ARGS_FILE"
+    [ "$(argv --device)" = "Vulkan0" ]
+    # The flag that must never appear: there is no thread count to set in this
+    # build (it comes from hardware_concurrency()/2), so naming one would only
+    # disagree with what the binary sized its pools from.
     ! grep -qE -- '^--?t$|^--threads$' "$ARGS_FILE"
 }
 
+@test "an empty device value is the CPU rollback: no --device reaches argv" {
+    # The same entrypoint with one key cleared, which is the rollback the env
+    # header documents. A script-level default that survived an explicitly empty
+    # value would leave the endpoint on the iGPU with no way back except a
+    # rebuild.
+    cat > "$TEST_TMP/fake-tts-server" <<'FAKE'
+#!/usr/bin/env bash
+printf '%s\n' "$@" > "$ARGS_FILE"
+FAKE
+    chmod +x "$TEST_TMP/fake-tts-server"
+    mkdir -p "$TEST_TMP/models"
+    : > "$TEST_TMP/models/$TALKER"
+    : > "$TEST_TMP/models/$CODEC"
+    export QWENTTS_MODEL="$TEST_TMP/models/$TALKER"
+    export QWENTTS_CODEC="$TEST_TMP/models/$CODEC"
+    export QWENTTS_BIN="$TEST_TMP/fake-tts-server"
+    export ARGS_FILE="$TEST_TMP/argv.txt"
+    export QWENTTS_DEVICE=""
+
+    run bash "$START"
+    [ "$status" -eq 0 ] || { echo "$output"; false; }
+    ! grep -qx -- '--device' "$ARGS_FILE"
+}
+
 @test "missing weights are a refusal that names the fetcher, before the port is bound" {
     cat > "$TEST_TMP/fake-tts-server" <<'FAKE'
 #!/usr/bin/env bash
@@ -627,17 +654,23 @@ PY
 @test "the image build is the pinned commit with the proven cmake line" {
     # GGML_BLAS=OFF is forced by the host (libopenblas.so.0 present, no dev
     # headers) and upstream's own Dockerfile passes it ON, so this file is not a
-    # copy of upstream on purpose. -j 8 and the OFF-for-every-GPU-backend list
+    # copy of upstream on purpose. -j 8 is what the 2026-10-18 trial ran;
-    # are what the 2026-10-18 trial ran.
+    # GGML_VULKAN=ON is the 2026-10-19 iGPU cutover, and the two greps below are
+    # the packages that door needs at build time and at run time.
     grep -qE '^ARG QWENTTS_COMMIT=[0-9a-f]{40}$' "$CF"
     grep -qF '5916bf7c79dbb4e66fc059cdc507a79a23a28bb4' "$CF"
     grep -qE 'git -C /src checkout --detach' "$CF"
     grep -qE 'submodule update --init' "$CF"   # ggml is a submodule; without it the build cannot configure
     for flag in -DGGML_CCACHE=OFF -DGGML_BACKEND_DL=OFF -DGGML_CPU_ALL_VARIANTS=OFF \
                 -DGGML_OPENMP=ON -DGGML_BLAS=OFF -DGGML_CUDA=OFF -DGGML_HIP=OFF \
-                -DGGML_VULKAN=OFF -DGGML_METAL=OFF -DGGML_SYCL=OFF -DGGML_RPC=OFF; do
+                -DGGML_VULKAN=ON -DGGML_METAL=OFF -DGGML_SYCL=OFF -DGGML_RPC=OFF; do
         grep -qF -- "$flag" "$CF" || { echo "build line lost $flag"; false; }
     done
+    # glslc is not in glslang-tools on this distro, and the configure fails
+    # without it; an image with the loader and no RADV ICD enumerates zero
+    # devices and dies in device lookup after the weights load.
+    grep -qE 'libvulkan-dev glslc spirv-headers' "$CF"
+    grep -qE 'libvulkan1 mesa-vulkan-drivers' "$CF"
     grep -qE 'cmake --build build -j 8' "$CF"
     # OpenMP on means the runtime stage needs the OpenMP runtime, and the probe
     # runs as /bin/sh -c, so the runtime stage needs curl.