Take the two main-thread disk reads off the startup path, and report what that bought

Both costs StrictMode found on a cold start are now off the main thread. scratchRoot is a Lazy<File>, so Context.getCacheDir - which checks and creates the private cache directory, measured at 492 ms - runs when a preview first copies something instead of while the view model is being created. The free-space probes moved into fillRootFreeSpace and fillFreeSpace, which run on Dispatchers.IO after the rows are already on screen and update the state when the filesystem answers; nothing waits for them, and fillFreeSpace checks the path is still the one on screen so a fast double-tap cannot leave a folder showing another one's number.

Measured after: StrictMode no longer reports either violation, and the only ones left are MIUI's own font hook - FontSettings.loadFontSetting, TypefaceUtils.loadFontSettings, InterceptorProxy.create via MainActivity.onCreate, in 50-78 ms pairs. The debug cold start went from a 1814 ms median to 1803 ms and the benchmark coldStart from 519.5/531.6 ms to 485.6/568.9/600.0 ms. That is no improvement, and PERFORMANCE.md says so in those words: both violations were first-call costs (cache directory creation once per install, a cold StatFs page cache), the timed runs are warm, and the device's run-to-run spread of 115 ms is wider than anything the change could have bought. What it does change is the launch right after an install, which is the benchmark's first iteration: 648 ms max fresh against 550 ms warm.
This commit is contained in:
2026-10-17 16:11:28 +02:00
parent cbb36abfce
commit 14615f9842
4 changed files with 91 additions and 12 deletions
+2 -2
View File
@@ -2,7 +2,7 @@
Generated from the source by `tools/make-code-map.py` - do not edit by hand. Regenerate it after a change (`python3 tools/make-code-map.py`); `--check` exits non-zero when this file is stale.
77 source files, 12741 lines - 33 test files, 386 tests. The behaviour index at the end lists every test name, and in this project a test name is a sentence about what the app does, so it doubles as the specification.
77 source files, 12793 lines - 33 test files, 386 tests. The behaviour index at the end lists every test name, and in this project a test name is a sentence about what the app does, so it doubles as the specification.
Start at `AGENTS.md`. What is done, and why: `docs/ROADMAP.md` and `CHANGELOG.md`. What was verified by hand rather than by a test: `docs/EDGE_CASE_TESTING.md`.
@@ -101,7 +101,7 @@ The browser screen: view model, state, list and grid, dialogs, selection bar
| `BrowserScreen.kt` | 591 | BrowserScreen() | - |
| `BrowserTopBar.kt` | 238 | The browser's app bar: title, up, the favourite star, and the search / sort / overflow actions. BrowserTopBar(), SEARCH_FIELD_WIDTH | `BrowserTopBarTest` (4) |
| `BrowserUiState.kt` | 311 | One immutable description of everything the browser shows. ViewMode, SearchScope, Clipboard, UiMessage, ConflictPrompt, RootItem, Bookmark, DetailFocus, Undo, UndoMove, Overlay, BrowserUiState | - |
| `BrowserViewModel.kt` | 2100 | Drives the browser screen. BrowserViewModel, ArchivePreview | `BrowserViewModelTest` (89) |
| `BrowserViewModel.kt` | 2152 | Drives the browser screen. BrowserViewModel, ArchivePreview | `BrowserViewModelTest` (89) |
| `DetailsSheet.kt` | 109 | Name, location, size, type and modified date for one entry. DetailsSheet(), DetailLines(), DetailLine() | - |
| `EntryIntents.kt` | 58 | Wraps an entry's path in a content:// URI another app may read. contentUriFor(), viewIntent(), shareIntent() | - |
| `IncomingBar.kt` | 60 | The bar shown while another app is waiting on this one. IncomingBar() | - |