gemini-cli/docs/CIPerformanceAnalysis.md

CI Optimization Report: Speedup & Lessons Learned

This report compares the total wall-clock time of the main branch workflows with our optimized Bundling Trial CI run.

Summary of Improvements

• Total Wall-Clock Time: Reduced from ~15 minutes to ~2 minutes! (Assuming we skip Mac tests for now, leaving only Linux E2E taking ~2m 13s!).
• Mac E2E Duration: Reduced from ~11 minutes to 3m 43s (when running tests).
• Linux E2E Duration: Reduced from ~7.7 minutes to 2m 13s.

Averages for Successful Runs in Last Week (Main Branch)

We calculated these averages across successful runs on the main branch over the last week:

• Mac CLI Jobs Average: 11.35 minutes
• Linux CLI Jobs Average: 7.06 minutes
• Mac Others Jobs Average: 6.09 minutes
• Linux Others Jobs Average: 3.39 minutes
• Average Total Wall-Clock Time for Commit to Main: 14.68 minutes (combining Testing: CI and Testing: E2E (Chained)).

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CLI UI Test Performance Analysis

This document details the performance of the test run for the packages/cli/src/ui folder, identifying the slowest test suites and individual tests.

Overview

• Total Time: ~297.43 seconds (~5 minutes)
• Total Tests: 4388
• Total Files: 435 (including non-UI tests if Vitest scanned them, but log shows UI tests mostly).

Slowest Test Suites (>= 2 seconds)

The following test suites took 2 seconds or longer to run:

Test Suite	Duration	Tests	Notes
src/ui/components/InputPrompt.test.tsx	32.74s	196	Very large file, handles complex input and scrolling.
src/ui/AppContainer.test.tsx	14.82s	107	Renders full app container, many tests taking ~100-300ms each.
src/ui/components/SkillInboxDialog.test.tsx	6.76s	11	High per-test overhead (~600ms each).
src/ui/components/shared/text-buffer.test.ts	6.63s	225	Many tests, some handling large text/ANSI.
src/ui/hooks/vim.test.tsx	5.87s	144	Simulates complex Vim keybindings.
src/ui/components/messages/ThinkingMessage.test.tsx	4.52s	8	Very high per-test overhead (~500ms each).
src/ui/components/ExitPlanModeDialog.test.tsx	4.36s	14	High per-test overhead (~300ms each).
src/ui/components/messages/ToolResultDisplay.test.tsx	4.20s	14	Tests rendering and scrolling of large output.
src/ui/components/SessionSummaryDisplay.test.tsx	3.93s	6	High per-test overhead (~600ms each).
src/ui/components/TextInput.test.tsx	3.97s	15	Tests input handling.
src/ui/components/Footer.test.tsx	3.86s	39	Renders footer with stats/memory.
src/ui/components/AskUserDialog.test.tsx	3.91s	42	Was faster before, might be affected by load.
src/ui/privacy/CloudFreePrivacyNotice.test.tsx	3.39s	9	High per-test overhead (~300ms each).
src/ui/components/shared/BaseSettingsDialog.test.tsx	3.34s	33	Was faster before, might be affected by load.
src/ui/components/shared/performance.test.ts	2.95s	3	One test alone takes 2.5s (character-by-character insertion).
src/ui/utils/MarkdownDisplay.test.tsx	2.72s	30	Tests markdown rendering.
src/ui/components/messages/ToolGroupMessage.test.tsx	2.77s	38	Renders tool groups.
src/ui/components/messages/ToolGroupMessage.compact.test.tsx	2.44s	4	High per-test overhead (~600ms each).
src/ui/components/messages/DiffRenderer.test.tsx	2.03s	26	Tests diff rendering.
src/ui/components/messages/ShellToolMessage.test.tsx	2.03s	16	Tests shell output rendering.
src/ui/components/ValidationDialog.test.tsx	2.08s	8	High per-test overhead (~250ms each).

Key Insights

1. InputPrompt.test.tsx is by far the biggest offender (32.7s). It has many tests and likely involves time-dependent behavior or large renders.
2. AppContainer.test.tsx is slow due to the volume of tests (107) and the complexity of the component being rendered.
3. Several suites have very few tests but take many seconds (e.g., TopicMessage in other runs, ThinkingMessage here taking 4.5s for 8 tests). This suggests high setup/teardown costs or rendering delays.
4. performance.test.ts has a test that deliberately tests slow insertion, taking 2.5s.

Recommendations

• Prioritize InputPrompt.test.tsx for global fake timers or splitting.
• Investigate test suites with high per-test overhead (e.g., ThinkingMessage, SessionSummaryDisplay).