Files
OpenFrontIO/tests/perf
Evan 8da2291a49 Add full-game perf harness for the core simulation (#4228)
## Summary

Adds a full-game performance harness under `tests/perf/fullgame/` that
runs the **real simulation pipeline** headlessly — `GameRunner` +
`Executor` with the real `Config`, nations from the map manifest, and
bots on a production map from `resources/maps/` — for a configurable
number of ticks, then reports where the time goes.

```bash
npm run perf:game                                        # world, 400 bots, 1800 ticks
npm run perf:game -- --map giantworldmap --ticks 3600
npm run perf:game -- --no-exec-profile                   # purest CPU profile (no timing wrappers)
```

## What it reports

1. **Per-tick wall time** — mean / p50 / p95 / p99 / max, count of ticks
over the 100ms budget, and the slowest ticks by tick number.
2. **Time per Execution class** — every `Execution`'s `init()`/`tick()`
is timed and aggregated by class name (`AttackExecution`,
`NationExecution`, …).
3. **Top functions by self time** — via the V8 sampling profiler
(`node:inspector`), so no instrumentation skew. Also writes a
`.cpuprofile` to `tests/perf/output/` (gitignored) that opens in Chrome
DevTools as a flame graph.

## Determinism

The run is fully deterministic for a given `--seed`/`--map`/`--bots`
(verified: identical final hashes across runs), and the final game-state
hash is printed — so an optimization can be checked to not change
simulation behavior.

## Sample output (world, 400 bots, 1800 ticks)

```
--- Per-tick wall time (game phase) ---
mean 9.04ms | p50 7.90ms | p95 17.1ms | p99 21.5ms | max 31.7ms
Over 100ms budget: 0 / 1800 ticks

--- Time by Execution class ---
execution                      total ms  %     tick ms  init ms  ticks   instances
AttackExecution                6568      48.8  6288     280      212536  4200
PlayerExecution                2832      21.0  2832     0.36     492049  472
NationExecution                2508      18.6  2508     0.23     144654  72
TransportShipExecution         703       5.2   96.0     607      30440   257
...

--- Top functions by self time (V8 sampling profiler) ---
self ms  %    function                 location
1065     6.5  forEachNeighborWithDiag  src/core/game/GameImpl.ts
979      6.0  conquer                  src/core/game/GameImpl.ts
948      5.8  (anonymous)              src/core/execution/AttackExecution.ts
595      3.6  toFullUpdate             src/core/game/PlayerImpl.ts
...
```

The harness lives in a subdirectory so the existing `npm run perf`
micro-benchmark runner (which globs `tests/perf/*.ts`) doesn't pick it
up.

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

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-06-11 18:52:18 -07:00
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