1k Startup Profile

Startup Profile — deep per-module + HBC + segment timing

Single env-var flag ONEKEY_STARTUP_PROFILE=1 turns on three layers of measurement at once. When OFF (the default), every measurement path is a single boolean check — zero observable overhead in production.

What gets measured

How to enable

Method 1 — build-time env var (production-capable)

Export before any of the build commands:

export

# JS bundle: Metro plugin picks it up and prepends
#   globalThis.__ONEKEY_STARTUP_PROFILE__ = true
#   globalThis.__ONEKEY_MODULE_ID_TO_PATH__ = {...}
# to the main entry bundle.
yarn app:android           # or `yarn app:ios` / EAS build command

# iOS native: read from Info.plist key or Xcode scheme env
# Android native: read from BuildConfig.ONEKEY_STARTUP_PROFILE (auto-set by
# build.gradle from the same env var)

For EAS builds, set the env var in eas.json for the build profile you want to profile:

{
  "build": {
    "profile-startup": {
      "extends": "base",
      "env": {
        "ONEKEY_STARTUP_PROFILE": "1"
      }
    }
  }
}

Then eas build --profile profile-startup --platform android.

Method 2 — Xcode scheme env (iOS dev only)

Xcode → Product → Scheme → Edit Scheme → Run → Arguments → Environment Variables:

ONEKEY_STARTUP_PROFILE = 1

This is picked up by ProcessInfo.processInfo.environment at runtime — works only for debug iOS running from Xcode.

Method 3 — Release iOS via Info.plist

In Info.plist add (or let an xcconfig generate at build time):

<key>ONEKEY_STARTUP_PROFILE</key>
<true/>

Or an xcconfig that reads the env var:

ONEKEY_STARTUP_PROFILE = YES

Ship a profile-enabled TestFlight build to inspect real-device release timings.

What shows up in the log when enabled

Cold-start sequence (Android, ~2.5s to TTI):

[StartupTiming] android.app.on_create.start: +0ms from launch (anchor)
...existing native instrumentation...
[StartupProfile.hbc] android.index.android.bundle: io=35ms size=18900000B (prewarm, at +180ms from launch)
[StartupTiming] main_host.did_start: +318ms from launch (android)
...
[StartupTiming] MMKV contextAtom snapshot pre-read: 10 keys (+121ms)
[StartupProfile.seg] 22ms id=3288 key=seg:nm.@formatjs path=segments/nm._formatjs.seg.hbc
[StartupProfile.seg] 12ms id=3311 key=seg:shared.locale.json.zh_CN.json path=...
[StartupProfile.seg] 230ms id=3021 key=seg:kit.provider.Container.KeylessWalletContainer.KeylessWalletContainer path=...
...
[StartupTiming] main entry evaluated (+1780ms)
[StartupProfile.js] summary: tracked=187 modules timed (>=1ms), sum_self=1524ms, sum_inclusive=3847ms, flushing top 200 by self-time
[StartupProfile.js] self=142ms total=189ms packages/kit/src/provider/Container/PrimeLoginContainer/PrimeLoginContainer.tsx
[StartupProfile.js] self=87ms total=312ms packages/kit/src/states/jotai/contexts/tokenList/atoms.ts
[StartupProfile.js] self=64ms total=64ms node_modules/@walletconnect/core/dist/...
...etc up to 200 modules

Interpreting the numbers

[StartupProfile.js] — module-level

• self = time inside this module's own factory body excluding any nested require() calls. This is the actionable signal — a module with self=100ms actually costs 100ms of its own code.
• total = inclusive time — includes time spent in everything this module requires. Useful for identifying "roots" of slow subtrees (e.g. ./App might have self=5ms total=1600ms).
• Only modules ≥ 1ms are recorded; sub-ms is filtered to avoid swamping the log with thousands of near-zero entries.
• The measurement patches Metro's __r (require), NOT __d (define). Reason: by the time our JS code runs, __d has already registered all factories with the unwrapped version — too late to wrap. __r is what runs the factory lazily, so wrapping it captures every first-time module load regardless of patch timing.

[StartupProfile.hbc] — main bundle file I/O

• io is pure OS-level read time (open → EOF).
• We can't directly measure Hermes bytecode parse time from the outside; instead compute parse+exec = <native ios.main_entry.evaluated> - io.
• Pre-warm side effect: after this probe the bundle is in the OS page cache. RN's subsequent load no longer pays I/O. If you want to measure non-warm-cache I/O, disable the probe for that run.
• Android probe is fire-and-forget on a MIN_PRIORITY thread to not stall Application.onCreate.

[StartupProfile.seg] — segment load

• Single aggregate per segment: combined I/O + Hermes parse + register. Splitting these would need a patch to @onekeyfe/react-native-split-bundle-loader; for now the aggregate is enough to identify the slowest segments.
• The relative-path suffix tells you which file in the segment dir is the culprit.

Cross-platform check: are both sides reading the same flag?

Grep the startup log after enabling:

grep 'StartupProfile' app-latest.log | head -5

Expected: at least one [StartupProfile.js], [StartupProfile.hbc], [StartupProfile.seg] line. If only some show up:

Zero-overhead guarantee when disabled

Each layer's code path when ONEKEY_STARTUP_PROFILE is not set:

• JS: isStartupProfileEnabled() reads globalThis.__ONEKEY_STARTUP_PROFILE__ (undefined → false), function returns, no patching, no allocation.
• iOS native: isStartupProfileEnabled() checks ProcessInfo env and Info.plist, returns false, skips the Data(contentsOf:) probe.
• Android native: if (BuildConfig.ONEKEY_STARTUP_PROFILE) — dead-code eliminated at compile time when false.
• Segment logs: if ((globalThis as any).__ONEKEY_STARTUP_PROFILE__ === true) — one identity check per segment load, sub-µs.

Production release bundle overhead when flag is off: ≈ 0. No removal needed, instrumentation can live in the main branch permanently.

Files touched

Parsing script (quick aggregation)

LOG=path/to/app-latest.log

# JS modules sorted by self-time (what you really want to know)
grep '\[StartupProfile\.js\] self=' "$LOG" | head -30

# Total JS cost of top 20 modules
grep '\[StartupProfile\.js\] self=' "$LOG" \
  | head -20 | awk '{sum+=$3} END {print sum}' \
  | sed 's/self=//'

# Segment slowest 10
grep '\[StartupProfile\.seg\]' "$LOG" | sort -k2 -n -r | head -10

# HBC I/O vs (ios.main_entry.evaluated - io)
grep 'StartupProfile\.hbc\|ios.main_entry.evaluated\|android.index.android.bundle' "$LOG"

Caveats

1. Metro inline-requires transform moves top-level const X = require(...) to the first use-site. This is why we patch __r rather than __d. But module IDs are the same — patching is safe.
2. Inclusive time sum_inclusive will be much larger than sum_self because every nested require is counted in each parent. Don't add them naively to reason about total time.
3. Segment split (I/O vs parse) requires patching @onekeyfe/react-native-split-bundle-loader. Not done yet. The combined number is usually enough for triage.
4. Dev / debug builds include source maps + extra instrumentation — numbers will be 2-3× higher than Release. Profile Release builds for real baselines.
5. Flag is build-time, not runtime: to toggle, rebuild. This is deliberate — zero overhead when off, and avoids the complexity of a Dev Settings toggle + MMKV sync across JS/native at startup.