Files
OpenFrontIO/tests/PlayerImpl.test.ts
T
Evan 5e4b2791aa perf: reduce core-sim GC churn 42% and add GC-churn profiling to the perf harness (#4494)
## Summary

Reduces core-simulation GC churn by **42%** on a 20-game-minute Giant
World Map run, and extends the headless full-game perf harness so churn
is measurable and regressions are visible.

### 1. GC-churn measurement (`tests/perf/fullgame/GcProfiler.ts`)

`npm run perf:game` now reports:

- **GC pauses** by kind (minor/major/incremental) via a
`PerformanceObserver` on `'gc'` entries, bucketed into tick windows by
timestamp (V8 only delivers these entries on a timer task, so they're
flushed after the run)
- **Allocation rate** per `--window N` ticks (default 1000) from
used-heap deltas sampled every tick, so churn can be tracked across game
phases
- **Top allocating functions** from the V8 sampling heap profiler with
`includeObjectsCollectedBy{Major,Minor}GC` — i.e. actual churn including
short-lived garbage, not live memory — plus a `.heapprofile` loadable in
Chrome DevTools (Memory → Allocation sampling)

New flags: `--window N`, `--no-gc-profile`, `--no-alloc-profile`.

### 2. Allocation reductions in the hot paths it found

| Site | Change |
|---|---|
| `GameMap.bfs` | inline neighbor enumeration instead of an array per
visited tile |
| `GameMap`/`Game` | new `forEachNeighborNSWE` — allocation-free
iterator matching `neighbors()` N,S,W,E order for order-sensitive
callers (`forEachNeighbor` visits W,E,N,S, so substituting it would
change sim behavior) |
| `PlayerImpl.nearby` / `sharesBorderWith` / `shoreReachableNeighbors` |
no per-call neighbor arrays; no materialized shore-tile array |
| `PlayerImpl.units(types)` | gather into a reusable scratch buffer,
return one exact-size slice (still a fresh snapshot array per call) |
| `AiAttackBehavior.maybeAttack` | single pass over border neighbors
replacing the `flatMap`/`filter`/`map` chain over every border tile |
| `AiAttackBehavior.isBorderingNukedTerritory` | reusable `neighbors4`
buffer with early exit |
| `SharedWaterCache.build` | allocation-free neighbor iteration |
| `SpatialQuery.bfsNearest` | first-minimum scan instead of
collect-then-stable-sort (identical result incl. tie-breaking) |

### Results (Giant World Map, 400 bots, 12,000 ticks ≈ 20 game-minutes,
seed `perf-default`)

| Metric | Before | After |
|---|---|---|
| Sampled allocations (incl. collected) | 97.7 GB | **56.9 GB (−42%)** |
| GC count / total pause | 1,682 / 3,313 ms (1.8% of wall) | 1,058 /
2,087 ms (1.2%) |
| Ticks/sec | 66 | 70 |
| p99 / max tick | 49.9 ms / 988 ms | 43.5 ms / 689 ms |
| Ticks over 100 ms budget | 31 | 19 |

## Determinism

Every rewrite preserves exact iteration order (the new NSWE iterator
exists precisely for the order-sensitive sites). Verified by identical
final game-state hashes on three runs: Giant World Map 12,000 ticks
(`67286276735690560`), Giant World Map 2,000 ticks, and World 1,800
ticks.

## Test plan

- [x] Full suite green (1,896 tests)
- [x] New tests: `forEachNeighborNSWE` order contract vs `neighbors()`
over every tile; `units()` filtering semantics (insertion order,
fresh-array guarantee, duplicate types, Set path)
- [x] Final-hash equality on 3 seeded headless runs (2 maps)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-07-03 12:30:28 -07:00

147 lines
4.6 KiB
TypeScript

import {
Game,
Player,
PlayerInfo,
PlayerType,
UnitType,
} from "../src/core/game/Game";
import { setup } from "./util/Setup";
let game: Game;
let player: Player;
let other: Player;
describe("PlayerImpl", () => {
beforeEach(async () => {
game = await setup("plains", { instantBuild: true }, [
new PlayerInfo("player", PlayerType.Human, null, "player_id"),
new PlayerInfo("other", PlayerType.Human, null, "other_id"),
]);
player = game.player("player_id");
other = game.player("other_id");
player.conquer(game.ref(0, 0));
other.conquer(game.ref(50, 50));
player.addGold(BigInt(1000000));
game.config().structureMinDist = () => 10;
});
test("City can be upgraded", () => {
const city = player.buildUnit(UnitType.City, game.ref(0, 0), {});
const buCity = player
.buildableUnits(game.ref(0, 0))
.find((bu) => bu.type === UnitType.City);
expect(buCity).toBeDefined();
expect(buCity!.canUpgrade).toBe(city.id());
});
test("DefensePost cannot be upgraded", () => {
player.buildUnit(UnitType.DefensePost, game.ref(0, 0), {});
const buDefensePost = player
.buildableUnits(game.ref(0, 0))
.find((bu) => bu.type === UnitType.DefensePost);
expect(buDefensePost).toBeDefined();
expect(buDefensePost!.canUpgrade).toBeFalsy();
});
test("City can be upgraded from another city", () => {
const city = player.buildUnit(UnitType.City, game.ref(0, 0), {});
const cityToUpgrade = player.findUnitToUpgrade(
UnitType.City,
game.ref(0, 1),
);
expect(cityToUpgrade).toBeTruthy();
if (cityToUpgrade === false) {
return;
}
expect(cityToUpgrade.id()).toBe(city.id());
});
test("City cannot be upgraded when too far away", () => {
player.buildUnit(UnitType.City, game.ref(0, 0), {});
const cityToUpgrade = player.findUnitToUpgrade(
UnitType.City,
game.ref(50, 50),
);
expect(cityToUpgrade).toBe(false);
});
test("Unit cannot be upgraded when not enough gold", () => {
player.buildUnit(UnitType.City, game.ref(0, 0), {});
player.removeGold(BigInt(1000000));
const cityToUpgrade = player.findUnitToUpgrade(
UnitType.City,
game.ref(0, 1),
);
expect(cityToUpgrade).toBe(false);
});
describe("units() type filtering", () => {
beforeEach(() => {
player.buildUnit(UnitType.City, game.ref(0, 0), {});
player.buildUnit(UnitType.DefensePost, game.ref(11, 0), {});
player.buildUnit(UnitType.City, game.ref(0, 11), {});
player.buildUnit(UnitType.MissileSilo, game.ref(11, 11), {});
});
// Reference implementation: filter _units preserving insertion order.
function expected(...types: UnitType[]) {
const ts = new Set(types);
return player.units().filter((u) => ts.has(u.type()));
}
test("single type returns matching units in insertion order", () => {
expect(player.units(UnitType.City)).toEqual(expected(UnitType.City));
expect(player.units(UnitType.City)).toHaveLength(2);
});
test("returns a fresh array, not the internal or shared buffer", () => {
const a = player.units(UnitType.City);
const b = player.units(UnitType.City);
expect(a).not.toBe(b);
expect(a).not.toBe(player.units());
// Mutating one result must not affect a later query.
a.length = 0;
expect(player.units(UnitType.City)).toHaveLength(2);
});
test("two and three types return the union in insertion order", () => {
expect(player.units(UnitType.City, UnitType.MissileSilo)).toEqual(
expected(UnitType.City, UnitType.MissileSilo),
);
expect(
player.units(UnitType.City, UnitType.DefensePost, UnitType.MissileSilo),
).toEqual(
expected(UnitType.City, UnitType.DefensePost, UnitType.MissileSilo),
);
// Duplicate types don't duplicate results.
expect(player.units(UnitType.City, UnitType.City)).toEqual(
expected(UnitType.City),
);
});
test("four or more types (Set path) and no match", () => {
expect(
player.units(
UnitType.City,
UnitType.DefensePost,
UnitType.MissileSilo,
UnitType.Port,
),
).toEqual(
expected(UnitType.City, UnitType.DefensePost, UnitType.MissileSilo),
);
expect(player.units(UnitType.Port)).toEqual([]);
});
});
test("Can't send alliance requests when dead", () => {
// conquer other
const otherTiles = other.tiles();
for (const tile of otherTiles) {
player.conquer(tile);
}
expect(other.canSendAllianceRequest(player)).toBe(false);
});
});