Auto Perf Optimize

*
!README.md
!.gitignore


# Scratchpad — one-off scenario runners

This folder is gitignored. Write investigation-specific runners here freely.

## Organization

Put each investigation in a **dated subfolder** named `YYYY-MM-DD-short-description/`:

```
scratchpad/
  2026-04-09-chat-scroll-leak/
    scenario.mts
    findings.md
  2026-04-12-editor-tab-switching/
    scenario.mts
    findings.md
```

Each subfolder should contain:

- **Scripts** — scenario runners, analysis scripts, etc.
- **`findings.md`** — a summary of the investigation: all ideas considered, whether each led to a change or was rejected (and why), and before/after measurements so the user can review decisions and follow up.

Scenario runners you create here can import utilities from the checked-in
scripts or copy patterns from them. When a runner proves generally useful,
promote it to the parent `scripts/` folder.

## Quick start

```bash
# Write a runner
cat > scratchpad/my-scenario.mts << 'EOF'
import { chromium } from 'playwright-core';
// ... your scenario
EOF

# Run it
node .github/skills/auto-perf-optimize/scratchpad/my-scenario.mts
```

## Checked-in scripts (in `scripts/`)

These are reusable, generic runners. Use them directly or as templates:

- **`chat-memory-smoke.mts`** — Multi-turn chat smoke runner. Sends prompts,
  waits for responses, samples heap, takes optional snapshots. Supports
  `--message`, `--iterations`, `--skip-send`, `--keep-open`, `--reuse`, etc.

- **`chat-session-switch-smoke.mts`** — Creates multiple chat sessions with
  different content, then repeatedly switches between them via the sessions
  sidebar. Measures per-switch memory growth.

- **`userDataProfile.mts`** — Utility for managing user-data profiles in
  smoke test runs.

## Tips

- Always use `--user-data-dir .build/auto-perf-optimize/user-data` (the
  persistent profile with Copilot auth). Never create a fresh user-data-dir.
- Use `--skip-prelaunch` to avoid re-downloading Electron on every run.
- If you need to clean up an orphaned test instance, stop only the specific
  Code - OSS process (e.g. by killing the PID that was logged at launch, or
  `lsof -ti :<port> | xargs kill`). Avoid `pkill -f 'Electron'` — it can
  kill unrelated Electron apps.
- For heap snapshot analysis, use the `heap-snapshot-analysis` skill's
  scratchpad and helpers.


/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

/**
 * Chat memory smoke runner.
 *
 * Intended workflow:
 * - Run `node .github/skills/auto-perf-optimize/scripts/chat-memory-smoke.mts --iterations 3 --no-heap-snapshots` for a fast health check.
 * - Run `node .github/skills/auto-perf-optimize/scripts/chat-memory-smoke.mts --iterations 8 --heap-snapshot-label 03-iteration-01 --heap-snapshot-label 03-iteration-08` when comparing post-warmup heap snapshots.
 * - Inspect the output folder's summary.json, screenshots, and optional heap/*.heapsnapshot files.
 *
 * The default profile is persistent at .build/auto-perf-optimize/user-data so auth can be reused across performance runners.
 * Pass --temporary-user-data when a clean, disposable profile is required; combine it with --seed-user-data-dir to start from a logged-in seed.
 */

import { chromium, type Browser, type CDPSession, type Locator, type Page } from 'playwright-core';
import { spawn, type ChildProcess } from 'node:child_process';
import { createWriteStream } from 'node:fs';
import { mkdir, rm, writeFile } from 'node:fs/promises';
import http from 'node:http';
import os from 'node:os';
import path from 'node:path';
import process from 'node:process';
import { setTimeout as timeout } from 'node:timers/promises';
import { StopWatch } from '../../../../src/vs/base/common/s