fix(frank-tts): the warm hook died on the kernel argument cap; the cold-voice law is retired by measurement #15

Merged
dank merged 2 commits from fix/frank-tts-warm-argv into main 2026-10-18 18:50:01 -07:00
6 changed files with 128 additions and 27 deletions
+35 -14
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@@ -16,17 +16,17 @@
# voice that did not warm becomes a deploy result instead of only a journal # voice that did not warm becomes a deploy result instead of only a journal
# line (the unit's `-` prefix deliberately cannot fail the unit). # line (the unit's `-` prefix deliberately cannot fail the unit).
# #
# WHY IT EXISTS AT ALL (the cold-voice law). The FIRST speech request for a # WHY IT EXISTS AT ALL (the registry law). The voice registry is MEMORY ONLY: a
# registered voice decodes the whole reference clip to snapshot its codec state: # restart forgets every voice, and re-registering a voice does not warm it — only
# 6.2-8.0 s, first audio byte at 5,530 ms. Every later request for that voice # synthesizing does. A boot that registers nothing therefore leaves frank-tts
# restores the snapshot in 0.5 ms. Two facts make that a boot problem rather than # answering 400 for every name, so this script registers every pack it finds. The
# a curiosity: the voice registry is MEMORY ONLY (a restart forgets every voice), # per-voice cold penalty is real but small, and smaller than the trial reported:
# and re-registering a voice does not warm it — only synthesizing does. So a boot # measured on the deployed build 2026-10-18 against an empty registry, the FIRST
# that registers the voices and stops leaves the first caller of the day paying # synthesis of a freshly registered voice cost 1,883 ms against 1,226-1,283 ms for
# 5.5 s of silence. This script speaks one short sentence per voice instead, then # the requests after it — about 0.6 s, not the trial's 6.2-8.0 s. Each voice gets
# speaks a second one so the journal carries the warm number too: the line # two identical requests so the journal carries both numbers, `voice <name>
# `voice <name> cold=…ms warm=…ms` is the repo's standing proof that the second # cold=…ms warm=…ms`; cold ≈ warm is the expected shape, and a large gap is what
# request of a voice answers well under a second. # would mean the snapshot path is broken.
# #
# THE VOICES. /voices — the host directory /home/dank/voices mounted read-only by # THE VOICES. /voices — the host directory /home/dank/voices mounted read-only by
# the unit, the same packs frank-tts mounts for its own name list. A pack is a # the unit, the same packs frank-tts mounts for its own name list. A pack is a
@@ -47,7 +47,9 @@
# #
# NOTHING HERE IS A SECRET, and nothing is logged that could be: the audio bytes # NOTHING HERE IS A SECRET, and nothing is logged that could be: the audio bytes
# are discarded, the synthesized text comes from the env file, and the reference # are discarded, the synthesized text comes from the env file, and the reference
# clip is base64'd straight into the request body without ever being echoed. # clip is base64'd into a request body that is written to a temporary file and
# handed to curl as `@file` — never echoed, and never placed on a command line,
# because of the size law explained at the mktemp below.
set -euo pipefail set -euo pipefail
# The engine's own address, from inside its namespace. Loopback is valid HERE: # The engine's own address, from inside its namespace. Loopback is valid HERE:
@@ -103,6 +105,18 @@ fi
warm_json="${warm_text//\\/\\\\}" warm_json="${warm_text//\\/\\\\}"
warm_json="${warm_json//\"/\\\"}" warm_json="${warm_json//\"/\\\"}"
# The registration body is a FILE, never an argument. The kernel caps a single
# command-line string at 32 pages — MAX_ARG_STRLEN = 131,072 bytes — and a shipped
# reference clip base64's to about 1.27 MB, so passing the body as one argument
# fails with E2BIG before curl is even executed. The first real boot of the unit
# (2026-10-18, the three shipped packs) proved it end to end: `/usr/bin/curl:
# Argument list too long` for every voice, reported as the misleading
# "registration failed (HTTP no response)". `mktemp` lands in the container's
# /tmp as the unprivileged `tts` user; one file for the whole pass, overwritten
# per voice, removed on any exit — it is container scratch, not host state.
body_file="$(mktemp -t frank-tts-warm.XXXXXX)"
trap 'rm -f "$body_file"' EXIT
fail=0 fail=0
log() { printf 'frank-tts-engine-warm: %s\n' "$*"; } log() { printf 'frank-tts-engine-warm: %s\n' "$*"; }
@@ -146,9 +160,16 @@ for dir in "$VOICES_DIR"/*/; do
continue continue
fi fi
body="$(printf '{"name":"%s","wav_b64":"%s"}' "$name" "$(base64 -w0 "${dir}reference.wav")")" # The audio enters through a redirection rather than a command substitution:
# the file is several hundred KB, and both a shell variable and an argument of
# that size are what this script used to die on.
{
printf '{"name":"%s","wav_b64":"' "$name"
base64 -w0 "${dir}reference.wav"
printf '"}'
} > "$body_file"
if ! code="$(curl -sS --max-time "$REQUEST_TIMEOUT" -o /dev/null -w '%{http_code}' \ if ! code="$(curl -sS --max-time "$REQUEST_TIMEOUT" -o /dev/null -w '%{http_code}' \
-H 'Content-Type: application/json' --data-binary "$body" \ -H 'Content-Type: application/json' --data-binary "@${body_file}" \
"${ENGINE_URL}/v1/audio/voices")" || [[ "$code" != "200" ]]; then "${ENGINE_URL}/v1/audio/voices")" || [[ "$code" != "200" ]]; then
log "voice '${name}': registration failed (HTTP ${code:-no response}) — the shim will answer 400 for this name" log "voice '${name}': registration failed (HTTP ${code:-no response}) — the shim will answer 400 for this name"
fail=1 fail=1
@@ -50,17 +50,17 @@ The spread is the whole argument: at ±0.01 the engine finishes synthesizing 1.5
## Three laws this service lives under ## Three laws this service lives under
**1. The cold-voice law → the unit warms at boot.** The **first** speech request for a registered voice decodes the whole reference clip to snapshot its codec state: **6.2–8.0 s, first audio byte at 5 530 ms**. Every later request for that voice restores the snapshot in **0.5 ms**. Registrations live in memory only — a restart forgets every voice — and re-registering does **not** warm a voice, only synthesizing does. So `frank-tts-engine.container` carries **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
``` ```
ExecStartPost=-/usr/bin/podman exec frank-tts-engine /app/warm-voices.sh ExecStartPost=-/usr/bin/podman exec frank-tts-engine /app/warm-voices.sh
TimeoutStartSec=900 TimeoutStartSec=900
``` ```
and the warm pass runs on every start including boot. Without it, whoever asks for audio first that day pays 5.5 s of silence. The `-` prefix is load-bearing: with `Restart=always`, a warmer that exits non-zero would restart the container and crash-loop the endpoint forever. The hook is `podman exec` rather than a host script **because this container publishes nothing** — there is no address the host could dial — and a consequence worth knowing: an exec inherits the unit's `EnvironmentFile`, so the warmer's knobs (`VOICES_DIR`, `HEALTH_WAIT`, `WARM_TEXT`, `REQUEST_TIMEOUT`) live in `scripts/frank-tts-engine.env` beside the engine's own. The deployer runs the same hook a second time so a failed warm becomes a deploy result rather than only a journal line, and so the per-voice numbers land on the console: and the warm pass runs on every start including boot. What it buys is registration (mandatory) plus a measurably smaller first request — and the size of that saving is **not** the number the trial published. **Re-measured on the deployed build, 2026-10-18,** against an empty registry (register, then time the synthesis): the first request for `narrator1` cost **1 883 ms**, the second **1 283 ms**, the third **1 226 ms** — about **0.6 s** of saved silence. A ~110-word request cost **9.4 s** and then **9.8 s**, so request time tracks the audio generated, not snapshot state. The trial's **6.2–8.0 s / first audio byte 5 530 ms / later requests 0.5 ms** ladder does **not** reproduce here; the 0.5 ms figure is an internal state-restore cost that was never an end-to-end request time, and the honest claim is the ~0.6 s above. The `-` prefix is load-bearing: with `Restart=always`, a warmer that exits non-zero would restart the container and crash-loop the endpoint forever. The hook is `podman exec` rather than a host script **because this container publishes nothing** — there is no address the host could dial — and a consequence worth knowing: an exec inherits the unit's `EnvironmentFile`, so the warmer's knobs (`VOICES_DIR`, `HEALTH_WAIT`, `WARM_TEXT`, `REQUEST_TIMEOUT`) live in `scripts/frank-tts-engine.env` beside the engine's own. The deployer runs the same hook a second time so a failed warm becomes a deploy result rather than only a journal line, and so the per-voice numbers land on the console:
``` ```
frank-tts-engine-warm: voice narrator1 cold=6821ms warm=412ms frank-tts-engine-warm: voice narrator1 cold=1402ms warm=1812ms
frank-tts-engine-warm: 3 voice(s) registered and warm frank-tts-engine-warm: 3 voice(s) registered and warm
``` ```
@@ -122,7 +122,7 @@ Nothing below has been run. Steps 1–5 are this service; 6–7 are what unblock
|---|---|---| |---|---|---|
| Unit restarts every 10 s, journal says `cannot read /models/…` | weights missing or the mount is empty | run the fetcher; re-deploy | | Unit restarts every 10 s, journal says `cannot read /models/…` | weights missing or the mount is empty | run the fetcher; re-deploy |
| Unit `active`, but every voice name returns 400 from the façade | the engine restarted and lost its in-memory registry, or the warm pass failed | `journalctl --user -u frank-tts-engine` for the warmer's lines; `podman exec frank-tts-engine /app/warm-voices.sh` | | Unit `active`, but every voice name returns 400 from the façade | the engine restarted and lost its in-memory registry, or the warm pass failed | `journalctl --user -u frank-tts-engine` for the warmer's lines; `podman exec frank-tts-engine /app/warm-voices.sh` |
| First request of the day is slow, the rest are fast | the warm pass did not run (the hook carries `-`, so it cannot fail the unit) | look for `did not answer` in the journal — the warmer gave up while the model was still loading | | Every voice logs `registration failed (HTTP no response)`, with `/usr/bin/curl: Argument list too long` on the line above it | the hook handed the registration body to curl as one argument: the kernel caps a single argument at 131 072 bytes (`MAX_ARG_STRLEN`), and a shipped `reference.wav` base64's to about 1.27 MB | the body goes through a temp file and `--data-binary @file` (2026-10-18). Any pack over ~96 KB trips this, so no small fixture can see it — the seam ships a 300 KB pack for exactly that reason |
| Everything is ~2× slower after a systemd tweak | a cpuset/cap pin changed `hardware_concurrency()` and the engine resized its thread pools | remove the pin (law 2) | | Everything is ~2× slower after a systemd tweak | a cpuset/cap pin changed `hardware_concurrency()` and the engine resized its thread pools | remove the pin (law 2) |
| `502` from the façade with `frank-tts upstream request failed` | the façade cannot resolve or reach the engine | `podman network inspect systemd-frank-tts-engine` and `podman inspect frank-tts --format '{{json .NetworkSettings.Networks}}'` — the façade must be attached to the bridge; a `127.0.0.1:8880` or `host.containers.internal:8880` upstream in `scripts/frank-tts.env` is the old shape and cannot work | | `502` from the façade with `frank-tts upstream request failed` | the façade cannot resolve or reach the engine | `podman network inspect systemd-frank-tts-engine` and `podman inspect frank-tts --format '{{json .NetworkSettings.Networks}}'` — the façade must be attached to the bridge; a `127.0.0.1:8880` or `host.containers.internal:8880` upstream in `scripts/frank-tts.env` is the old shape and cannot work |
| A voice is missing from the list | its directory has no `reference.wav`, or the name is not lowercase | fix the pack; both are refused loudly by design | | A voice is missing from the list | its directory has no `reference.wav`, or the name is not lowercase | fix the pack; both are refused loudly by design |
@@ -169,10 +169,14 @@ invariant to every crop in the tracked pack list.
curl -s localhost:7772/v1/audio/voices # the façade's list, not the engine's curl -s localhost:7772/v1/audio/voices # the façade's list, not the engine's
``` ```
The hook walks `/voices`, registers any pack with a `reference.wav` it has not The hook walks `/voices` and registers **every** pack that has a
seen, and logs `voice <name> cold=…ms warm=…ms` to the unit's journal. The `reference.wav`, on every run — the engine replaces a name it already holds
rootless unit restart — `systemctl --user restart frank-tts-engine.service` — (`tools/tts-server.cpp:148` at the pinned commit: *"Re-registering a name
is for when the unit or its env changed, not for a new pack. replaces the previous entry."*) — then synthesizes twice per voice and logs
`voice <name> cold=…ms warm=…ms` to the unit's journal. The two numbers should
be close; see law 1 of [[Frank TTS Engine]] for what they measure. The rootless
unit restart — `systemctl --user restart frank-tts-engine.service` — is for when
the unit or its env changed, not for a new pack.
## When the extractor's output size changes on an engine bump ## When the extractor's output size changes on an engine bump
@@ -258,11 +258,17 @@ HTTP path at all — that is what the façade's CLI backend exists for.
Four laws came out of the trial, each worth a line of configuration: Four laws came out of the trial, each worth a line of configuration:
- **Boot-warm every voice.** The first request for a registered voice decodes - **Boot-warm every voice.** The trial measured the first request for a
the whole reference to snapshot codec state: 6.2–8.0 s, first audio byte at registered voice at 6.2–8.0 s (first audio byte 5,530 ms) and later requests
5,530 ms. Later requests restore that state in 0.5 ms. An engine unit must restoring the snapshot in 0.5 ms. **That ladder did not survive deployment:**
run one throwaway synthesis per voice at start, or the first request of the measured 2026-10-18 on the built container against an empty registry — register,
day pays five seconds. then time — the first synthesis of a freshly registered voice cost **1,883 ms**
against **1,226–1,283 ms** for the requests after it, and a ~110-word request
cost **9.4 s** then **9.8 s**, so request time tracks the audio generated rather
than snapshot state. What still holds is the reason to warm at all: the registry
is memory-only and re-registering does not warm, so an engine unit must run one
throwaway synthesis per voice at start. It buys registration and about 0.6 s,
not five seconds.
- **Speaker artifacts are reusable and exact.** `qwen-codec` turns a reference - **Speaker artifacts are reusable and exact.** `qwen-codec` turns a reference
WAV into `.spk` (8,192 B x-vector) + `.rvq` (5,456–6,864 B, 16 codebooks × T, WAV into `.spk` (8,192 B x-vector) + `.rvq` (5,456–6,864 B, 16 codebooks × T,
11-bit packed) in 1.8–2.1 s at 1.3–1.5 GiB peak; replaying them yields a 11-bit packed) in 1.8–2.1 s at 1.3–1.5 GiB peak; replaying them yields a
+39
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@@ -2643,3 +2643,42 @@ every restart since the cutover.
and a new unit on a host that serves people — Frank's call), no voice pack and a new unit on a host that serves people — Frank's call), no voice pack
built on the host, no Playwright run (this branch publishes no host port and built on the host, no Playwright run (this branch publishes no host port and
touches no vhost), and Gitea **#2** phase 1 stays open until 7772 answers. touches no vhost), and Gitea **#2** phase 1 stays open until 7772 answers.
## 2026-10-18 — frank-tts-engine deployed: it builds, it serves, and the warm hook died on the kernel's argument cap
- Merged as **#14** (`747c665`) and deployed `--service frank-tts-engine`. The
payload took 18 s to fetch for the 1.4 GiB pair (byte count + Hub LFS sha256,
`--verify-only` OK), and the image built clean — the first real proof of the
`useradd` fix: `STEP 3/13: RUN useradd --system --uid 10000 …` passed with only
the documented cosmetic `SYS_UID_MAX` warning, and the unit was `healthy` after
31 s.
- Then the deploy reported `0 voice(s) warm`:
`/app/warm-voices.sh: line 152: /usr/bin/curl: Argument list too long`. The hook
handed the registration body to curl as ONE argument; the kernel caps a single
argument at 131,072 bytes (`MAX_ARG_STRLEN`) and a shipped 955 KB
`reference.wav` base64's to about 1.27 MB, so curl never executed and the hook
logged that as "HTTP no response". Fourth silent fault of the voice stack, same
species as the other three: `/health` stayed green throughout.
- Fix: the body goes to a `mktemp` file and curl gets `@file`. The regression test
is the honest shape — the seam's stub engine is a real listener, `curl` is the
real binary, the fixture pack is 300 KB — so it fails with the same kernel error
the host produced (proved red first, green after). Every shipped pack sits well
over the ~96 KB cliff, so no small fixture could ever have seen this.
- Live proof on the deployed container with the three real packs:
`narrator1 cold=1175ms warm=1874ms`, `narrator2 1373/1892`, `narrator3
1816/1487`, exit 0, 15.2 s for the whole pass.
- **A trial law did not survive deployment.** Against an empty registry —
register only, then time — the FIRST synthesis of a freshly registered voice
cost **1 883 ms**, the next two **1 283** and **1 226 ms**; a ~110-word request
cost **9.4 s** then **9.8 s**. The trial's 6.2–8.0 s cold / 0.5 ms restore
ladder, which the warmer's own header repeated, is retired: warming buys
registration — mandatory, because the registry is memory-only — plus about
**0.6 s**. Corrected in [[Frank TTS Engine]] law 1 and its troubleshooting
table, in [[Local TTS and Voice Cloning]], and in [[Voice Packs]].
- Host state, honestly: the engine is `active` with three voices warm, but the hook
fix is not in the image yet, so the next restart re-breaks it until this branch
is merged and re-deployed. `frank-tts` (the 7772 façade) is still undeployed.
- Deliberately NOT done in this window: the `frank-tts` deploy, any Prometheus
probe for the voice pair (neither container exposes `/metrics`; the blackbox
question is still open), and the podcast render — open-notebook is on `main` but
not installed.
+31
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@@ -394,6 +394,37 @@ assert {s["response_format"] for s in speech} == {"wav"}, speech
PY PY
} }
@test "a reference clip too big for one argument still registers" {
# The kernel caps a SINGLE command-line string at 32 pages = 131,072 bytes
# (MAX_ARG_STRLEN), and a shipped reference clip base64's to about 1.27 MB —
# so a warmer that hands the registration body to curl as an argument dies
# before curl runs. That is exactly what the first real boot of 2026-10-18
# hit with the real packs: `/usr/bin/curl: Argument list too long`, then the
# misleading "registration failed (HTTP no response)" for all three voices.
# The stub engine is a real listener and curl is the real binary, so this
# test fails for the same kernel reason the host did.
start_engine_stub
local big="$TEST_TMP/bigvoices/bigvoice"
mkdir -p "$big"
head -c 300000 /dev/zero | tr '\0' 'A' > "$big/reference.wav"
run env ENGINE_URL="http://127.0.0.1:$STUB_PORT" VOICES_DIR="$TEST_TMP/bigvoices" \
bash "$WARM"
[ "$status" -eq 0 ] || { echo "$output"; false; }
[[ "$output" == *"voice bigvoice cold="*"ms warm="*"ms"* ]] || { echo "$output"; false; }
# And the audio that arrived is the audio that was on disk, whole.
python3 - "$TEST_TMP/journal.jsonl" "$big/reference.wav" <<'PY'
import hashlib, json, sys
entries = [json.loads(l) for l in open(sys.argv[1])]
regs = [e for e in entries if e["path"] == "/v1/audio/voices"]
assert len(regs) == 1, entries
assert regs[0]["name"] == "bigvoice", regs[0]
want = hashlib.sha256(open(sys.argv[2], "rb").read()).hexdigest()
assert regs[0]["wav_sha256"] == want, (len(regs[0]["wav_sha256"]), want)
PY
}
@test "the warm sentence survives both readers of the env file intact" { @test "the warm sentence survives both readers of the env file intact" {
# scripts/frank-tts-engine.env is read two ways and they disagree about # scripts/frank-tts-engine.env is read two ways and they disagree about
# quotes. bash (`set -a; source`, what the seams and a human do) strips the # quotes. bash (`set -a; source`, what the seams and a human do) strips the