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8.91 kB
| // @ts-check | |
| /** | |
| * LFM3-Omni on WebGPU, off the main thread so the avatar keeps its frame rate. | |
| * One conversation lives here: the history, the prefix-cached session, and the | |
| * context budget. Everything the main thread needs comes back as a stream of events. | |
| * | |
| * main -> worker: | |
| * { kind: "load", model, system } | |
| * { kind: "respond", id, audio } a user turn, 16 kHz Float32 | |
| * { kind: "abort", id } barge-in: stop generating this turn | |
| * { kind: "system", system } new persona / instructions | |
| * { kind: "reset" } forget the conversation | |
| * | |
| * worker -> main: | |
| * { kind: "progress", loaded?, total?, fraction?, status? } | |
| * { kind: "ready", device, sampleRate } { kind: "failed", name, message } | |
| * { kind: "text", id, text } { kind: "audio", id, samples } | |
| * { kind: "finished", id, reason, usage, generated, error? } | |
| */ | |
| import { | |
| Lfm3OmniForConditionalGeneration as Model, | |
| ContextOverflowError, | |
| DeviceLostError, | |
| } from "../vendor/Lfm3OmniForConditionalGeneration.js"; | |
| const LOAD_ATTEMPTS = 4; // Chromium occasionally returns no adapter on a cold GPU process, and networks drop requests | |
| const LOAD_RETRY_MS = 1500; | |
| // Her replies stay in history as text only: her speech costs ~16 tokens/s and left | |
| // no room for what was said, so a 44-turn chat now fits and she still recalls it. | |
| // Past the budget half of it goes, well under the session's 8192 tokens. | |
| const SEARCH = new URL(location.href).searchParams; | |
| const HISTORY_BUDGET_TOKENS = Number(SEARCH.get("historyBudget")) || 6000; | |
| const PRE_SPEECH_SAMPLES = 1200; // keep 50 ms before her first sound | |
| /** @type {any} */ let model = null; | |
| /** @type {any} */ let session = null; | |
| let system = ""; | |
| /** @type {any[]} */ let history = []; | |
| let idle = Promise.resolve(); | |
| /** @type {AbortController | null} */ let rereading = null; | |
| /** @type {Map<number, AbortController>} */ | |
| const running = new Map(); | |
| const simulateRtf = Number(SEARCH.get("simulateRtf")) || 0; | |
| const holdLoadMs = Number(SEARCH.get("holdLoadMs")) || 0; // testing: stretch out the load | |
| const post = (msg, transfer = []) => self.postMessage(msg, { transfer }); | |
| function messages() { | |
| return [{ role: "system", content: system }, ...history]; | |
| } | |
| /** Forget the oldest user turn and everything answering it. */ | |
| function dropOldestExchange() { | |
| const next = history.findIndex((m, i) => i > 0 && m.role === "user"); | |
| if (next < 0) return false; | |
| history.splice(0, next); | |
| return true; | |
| } | |
| /** Past the budget half the history goes at once, so the next turn's one re-prefill buys many cheap turns. */ | |
| function compactHistory() { | |
| const exchanges = history.filter((m) => m.role === "user").length; | |
| for (let i = 0; i < Math.floor(exchanges / 2); i++) dropOldestExchange(); | |
| } | |
| /** The reply as history keeps it: what she said, not the sound of it. */ | |
| function textOnly(message) { | |
| if (!Array.isArray(message.content)) return message; | |
| return { ...message, content: message.content.filter((c) => c.type === "text").map((c) => c.text).join("") }; | |
| } | |
| /** | |
| * Settle the cache while she's idle, re-reading a trimmed history and rewinding | |
| * past her audio, so nobody waits for it on their next turn. Stops short of the last reply: the cache can only rewind to its end, | |
| * and this prompt's end must still be a prefix of the next one. | |
| */ | |
| async function reread(signal) { | |
| const stream = session.generate(messages().slice(0, -1), { generation_mode: "text", max_new_tokens: 1, signal }); | |
| for await (const _ of stream); | |
| await stream.result; | |
| } | |
| async function load({ model: modelId, system: sys }) { | |
| system = sys; | |
| let lastErr; | |
| for (let attempt = 1; attempt <= LOAD_ATTEMPTS; attempt++) { | |
| try { | |
| if (!navigator.gpu) { | |
| throw Object.assign(new Error("This browser doesn't support WebGPU."), { name: "WebGPUUnavailable" }); | |
| } | |
| post({ kind: "progress", status: "Checking your GPU" }); | |
| const check = await Model.checkAvailability(modelId); | |
| if (!check.ok && !/No WebGPU adapter/i.test(check.reason ?? "")) { | |
| throw Object.assign(new Error(check.reason), { name: "WebGPUUnavailable" }); | |
| } | |
| model = await Model.from_pretrained(modelId, { | |
| onProgress: (p) => { | |
| if (p.kind === "bytes" && p.total > 0) post({ kind: "progress", loaded: p.loaded, total: p.total }); | |
| else if (p.status === "ready") post({ kind: "progress", fraction: 1 }); | |
| else post({ kind: "progress", status: p.message ?? p.status }); | |
| }, | |
| }); | |
| session = model.create_session(); | |
| post({ kind: "progress", status: "Getting ready" }); | |
| await session.prime(messages()).result; | |
| if (holdLoadMs) await new Promise((r) => setTimeout(r, holdLoadMs)); | |
| post({ kind: "ready", device: model.deviceInfo(), sampleRate: model.audio_sampling_rate }); | |
| return; | |
| } catch (err) { | |
| lastErr = err; | |
| console.warn(`model load attempt ${attempt} failed:`, err); | |
| const adapterGlitch = /No WebGPU adapter/i.test(String(err?.message)); | |
| if (adapterGlitch && attempt === LOAD_ATTEMPTS) lastErr = Object.assign(new Error(err.message), { name: "WebGPUUnavailable" }); | |
| // A multi-gigabyte download over a real connection will sometimes drop a request. That's worth another go, after a growing pause; what's already cached isn't fetched again. | |
| const networkGlitch = /failed to fetch|networkerror|network error|load failed|err_/i.test(String(err?.message)); | |
| if ((!adapterGlitch && !networkGlitch) || attempt === LOAD_ATTEMPTS) break; | |
| await new Promise((r) => setTimeout(r, LOAD_RETRY_MS * 2 ** (attempt - 1))); | |
| } | |
| } | |
| post({ kind: "failed", name: lastErr?.name ?? "Error", message: lastErr?.message ?? String(lastErr) }); | |
| } | |
| /** One user turn. */ | |
| async function respond({ id, audio }) { | |
| const controller = new AbortController(); | |
| running.set(id, controller); | |
| const { signal } = controller; | |
| rereading?.abort(); | |
| const prior = idle; | |
| /** @type {() => void} */ let release = () => {}; | |
| idle = new Promise((r) => (release = r)); | |
| let reason = "stop"; | |
| let usage = null; | |
| let generated = 0; | |
| let error; | |
| try { | |
| await prior; | |
| signal.throwIfAborted(); | |
| history.push({ role: "user", content: [{ type: "audio", audio }] }); | |
| for (;;) { | |
| const stream = session.generate(messages(), { generation_mode: "interleaved", signal }); | |
| let emitted = false; | |
| const started = performance.now(); | |
| try { | |
| for await (const ev of stream) { | |
| if (ev.type === "text") { | |
| emitted = true; | |
| post({ kind: "text", id, text: ev.text }); | |
| } else if (ev.type === "audio") { | |
| emitted = true; | |
| let samples = ev.audio.slice(); | |
| if (generated === 0) { | |
| // Her replies open with ~0.8 s of silence. Don't make anyone wait for it. | |
| const start = samples.findIndex((v) => Math.abs(v) > 0.01); | |
| if (start < 0) continue; | |
| samples = samples.slice(Math.max(0, start - PRE_SPEECH_SAMPLES)); | |
| } | |
| generated += samples.length; | |
| if (simulateRtf) { | |
| const due = started + (generated / model.audio_sampling_rate / simulateRtf) * 1000; | |
| await new Promise((r) => setTimeout(r, Math.max(0, due - performance.now()))); | |
| } | |
| post({ kind: "audio", id, samples }, [samples.buffer]); | |
| } | |
| } | |
| } catch (err) { | |
| if (!emitted && err instanceof ContextOverflowError && dropOldestExchange()) continue; | |
| throw err; | |
| } | |
| const result = await stream.result; | |
| usage = result.usage; | |
| reason = result.finish_reason; | |
| history.push(textOnly(result.message)); | |
| break; | |
| } | |
| } catch (err) { | |
| if (err?.name === "AbortError" || signal.aborted) { | |
| reason = "cancelled"; | |
| } else { | |
| console.error(err); | |
| reason = "error"; | |
| error = { name: err?.name, message: err?.message ?? String(err), fatal: err instanceof DeviceLostError }; | |
| } | |
| } finally { | |
| running.delete(id); | |
| post({ kind: "finished", id, reason, usage, generated, error }); | |
| if (usage && !signal.aborted) { | |
| if (session.count_tokens(messages()).prompt_tokens > HISTORY_BUDGET_TOKENS) compactHistory(); | |
| rereading = new AbortController(); | |
| await reread(rereading.signal).catch((err) => { | |
| if (err?.name !== "AbortError" && !rereading?.signal.aborted) console.warn("re-read failed:", err); | |
| }); | |
| rereading = null; | |
| } | |
| release(); | |
| } | |
| } | |
| self.onmessage = ({ data }) => { | |
| switch (data.kind) { | |
| case "load": | |
| void load(data); | |
| break; | |
| case "respond": | |
| void respond(data); | |
| break; | |
| case "abort": | |
| running.get(data.id)?.abort(); | |
| break; | |
| case "system": | |
| system = data.system; | |
| break; | |
| case "reset": | |
| idle = idle.then(() => { | |
| history = []; | |
| }); | |
| break; | |
| } | |
| }; | |