| # Binary Size Metrics |
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| This document lists metrics used to track binary size. |
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| [TOC] |
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| ## Metrics for Desktop |
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| * Sizes are collected by |
| [//build/scripts/slave/chromium/sizes.py](https://cs.chromium.org/chromium/build/scripts/slave/chromium/sizes.py) |
| * [Win32 Telemetry Graphs](https://chromeperf.appspot.com/report?sid=b3dcc318b51f3780924dfd3d82265ca901ac690cb61af91919997dda9821547c) |
| * [Linux Telemetry Graphs](https://chromeperf.appspot.com/report?sid=bd18d34b6d29f26877e7075cb5c34c56c011d99803e9120d61610d7eaef38e9c) |
| * [Mac Telemetry Graphs](https://chromeperf.appspot.com/report?sid=2cb6e0a9941e63418e7b83f91583282fa9fbaaafc2d19b3fa1179b28e7d3f7eb) |
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| ### Alerting |
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| * Alerts are sheriffed as part of the main perf sheriff rotation. |
| * Alerts generally fire for ~100kb jumps. |
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| ## Metrics for Android |
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| For Googlers, more information available at [go/chrome-apk-size](https://goto.google.com/chrome-apk-size). |
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| * Sizes are collected by |
| [//build/android/resource_sizes.py](https://cs.chromium.org/chromium/src/build/android/resource_sizes.py). |
| * How to analyze Android binary size discussed in [apk_size_regressions.md#debugging-apk-size-increase](../apk_size_regressions.md#debugging-apk-size-increase). |
| * Sizes for `ChromePublic.apk`, `ChromeModernPublic.apk`, `TrichromeChrome.aab`, `SystemWebview.apk` are tracked. |
| * But only `TrichromeChrome.aab` is actively monitored. |
| * We care most about on-disk size (for users with small device storage) |
| * But also care about patch size (so that browser updates get applied) |
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| ### Normalized APK Size |
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| * [Telemetry Graph](https://chromeperf.appspot.com/report?sid=e55e2189727a5bc410196e8cb7492879f9a224dc1383c6cdf9409edc0a8a1050) |
| * Monitored by [Binary Size Sheriffs](../apk_size_regressions.md). |
| * Alerts fire for changes of 16kb or more. |
| * Computed as: |
| * The size of an APK |
| * With all native code as the sum of section sizes (except .bss), uncompressed. |
| * Why: Removes effects of ELF section alignment. |
| * With all dex code as if it were stored uncompressed. |
| * Why: Best practice is to store dex uncompressed on Android P and above. |
| * On prior versions, or when stored compressed, dex is extracted upon installation. |
| * With all zipalign padding removed. |
| * Why: Removes effects of file alignment (esp. relevant because native libraries are 4k-aligned). |
| * With size of apk signature block removed. |
| * Why: Size fluctuates by several KB based on how hash values turn out. |
| * With all translations as if they were not missing (estimates size of missing translations based on size of english strings). |
| * Why: Without translation-normalization, translation dumps cause jumps. |
| * Translation-normalization applies only to apks (not to Android App Bundles). |
| * For Android App Bundles, the normalized size is the sum of the normalized size of all splits that have onDemand="false" (those installed by default). |
| |
| ### Native Code Size Metrics |
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| * [Telemetry Graph](https://chromeperf.appspot.com/report?sid=7b392aa248c77bd4c4fe03ca870e30863e3dcb7f06167cb50c9d7d99010687a9) |
| * File size of `libchrome.so` |
| * Code vs data sections (.text vs .data + .rodata) |
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| ### Java Code Size Metrics |
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| * [Telemetry Graph](https://chromeperf.appspot.com/report?sid=d2f2a1dfefd89c43902299efeddf6e4e6521db5e01d3716b8202f6ad8ad960da) |
| * File size of `classes.dex` |
| * "Dex": Counts of the number of fields, methods, strings, types. |
| * "DexCache": The number of bytes of RAM required to load our dex file (computed from counts) |
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| ### Breakdown Metrics |
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| * [Telemetry Graph](https://chromeperf.appspot.com/report?sid=c7f4afc0f438e7868b81be12c44aca7d0e9f7379bf1ae862df261fcd28d222f1) |
| * Compressed size of each apk component. |
| * The sum of these equals APK Size (which can be found under "Install Size Metrics": "APK Size") |
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| ### Install Metrics |
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| * [Telemetry Graph](https://chromeperf.appspot.com/report?sid=33515ace819bc607a742c8748316ffe6a36b3fcbc598efd35cd80d0a83c190ae) |
| * Estimated installed size: How much disk is required to install Chrome on a device. |
| * This is just an estimate, since actual size depends on Android version (e.g. Dex overhead is very different for pre-L vs L+). |
| * Does not include disk used up by profile, etc. |
| * We believe it to be fairly accurate for all L+ devices (less space is required for Dalvik runtime pre-L). |
| * The sum of these equals Estimated installed size. |
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| ### Transfer Size Metrics |
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| * Deflated apk size: |
| * [Telemetry Graph](https://chromeperf.appspot.com/report?sid=c7dcbe09dee57f6dab19f9307acd97a044a150710357ad25bf217ce004b3b4bb) |
| * Only relevant for non-patch updates of Chrome (new installs, or manual app updates) |
| * Patch Size (no longer available): |
| * Is too slow to be running on the Perf Builder |
| * Was found to be fairly unactionable |
| * Used to use [https://github.com/googlesamples/apk-patch-size-estimator](https://github.com/googlesamples/apk-patch-size-estimator) |
| * Functionality now exists in `//third_party/android_sdk/public/cmdline-tools/latest/bin/apkanalyzer download-size` |
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| ### Uncompressed Metrics |
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| * [Telemetry Graph](https://chromeperf.appspot.com/report?sid=33f59871f4e9fa3d155be3c13a068d35e6e621bcc98d9b7b103e0c8485e21097) |
| * Uncompressed size of classes.dex, locale .pak files, etc |
| * Reported only for things that are compressed within the .apk |
