Owner ruling 2026-10-04: the module is a sunk cost, retrievable from history if ever revisited. Removed: core practice contracts + pipeline helpers, the PracticeStore port + adapter + data dir path, server service + API routes (sets, clusters picker, practice aborts), the practice pages + dialog/exam/list UI, chain-table's Generate handoff, sidebar nav, activity-dock practice rows, and the partitioner/ problemGenerator/grader model roles (BACKGROUND_MODEL_ROLES 8 → 5). Survivors, moved to core/chains.ts (pure + browser-safe): ReasoningChain, chainsForSelection, formatChainLine — the chain table and graph emission still consume them.
93 lines
3.2 KiB
TypeScript
93 lines
3.2 KiB
TypeScript
/**
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* THE SHARED BACKGROUND-LLM SEMAPHORE (owner ruling, 2026-09-29): ONE
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* process-wide pool of 3 permits for ALL background LLM jobs — extraction
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* chunks. Total background
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* LLM concurrency is bounded at 3, whoever is calling: no subsystem gets
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* a private lane past the provider-facing stance.
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*
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* Extraction owned this gate alone first (owner, 2026-09-28: at most 3
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* concurrent extractor calls).
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* the ruling then unified them — this module is the single truth, so
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* extraction chunks are the only holders.
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*
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* FIFO; abort-aware (a queued caller that aborts marks its ticket dead —
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* the permit handoff skips it and hands to the next waiter).
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*
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* FRESH-TAKE / HANDED-OFF-PERMIT discipline (the double-count deadlock
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* lesson, extraction 2026-09-28): fresh takers increment `active`
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* themselves; a HANDED-OFF permit does not (the releaser left `active`
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* untouched for the inheritor) — counting both sides is how a semaphore
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* slowly deadlocks at 3-with-empty-queue.
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*
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* The audit side needs no slot: audits serialize behind their own global
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* lock, so by the time a job releases its permit the audit queue is the
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* only remaining throttle.
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*/
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/** Total background LLM concurrency, process-wide, across ALL subsystems
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* (owner ruling 2026-09-29: one shared pool — extraction chunks +
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* extraction chunks). */
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const PERMIT_COUNT = 3;
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export interface LlmSlots {
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active: number;
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queue: { resolve: () => void; dead: boolean }[];
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}
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interface LhLlmSemaphoreGlobal {
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__lhLlmSlots?: LlmSlots;
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}
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/** The process's single permit pool (globalThis — Next dev compiles each
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* route entry as its own module instance; a module-level object would
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* split the pool per route. One process, one truth). */
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export function bgLlmSlots(): LlmSlots {
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const g = globalThis as typeof globalThis & LhLlmSemaphoreGlobal;
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return (g.__lhLlmSlots ??= { active: 0, queue: [] });
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}
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/** Run `critical` under one permit of the shared pool. `signal` (the
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* caller's row/abort controller) kills a queued ticket: it marks itself
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* dead and rejects AbortError — the handoff skips it. */
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export async function withBgLlmSlot<T>(
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signal: AbortSignal | undefined,
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critical: () => Promise<T>,
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): Promise<T> {
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const slots = bgLlmSlots();
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let freshTake = true;
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if (slots.active >= PERMIT_COUNT) {
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freshTake = false;
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await new Promise<void>((resolve, reject) => {
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const ticket: { resolve: () => void; dead: boolean } = { resolve, dead: false };
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slots.queue.push(ticket);
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if (!signal) return;
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const die = () => {
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ticket.dead = true; // the permit handoff must skip us
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const err = new Error("background LLM job aborted while queued for a permit");
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err.name = "AbortError";
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reject(err);
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};
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if (signal.aborted) die();
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else signal.addEventListener("abort", die, { once: true });
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});
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}
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if (freshTake) slots.active++;
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try {
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return await critical();
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} finally {
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// Permit handoff: a waiting ticket inherits the permit directly
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// (active stays); dead tickets are skipped — their job already
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// left through the abort path.
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for (;;) {
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const next = slots.queue.shift();
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if (!next) {
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slots.active--;
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break;
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}
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if (next.dead) continue;
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next.resolve();
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break;
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}
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}
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}
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