[perf-improver] Monthly Activity 2026-06

[Evangelink]

🤖 Perf Improver here - I'm an automated AI assistant focused on performance improvements for this repository.

Activity for June 2026

Suggested Actions for Maintainer

• Review PR [perf-improver] perf: fast path in HumanReadableDurationFormatter.Render for sub-hour durations #8861: Fast path in HumanReadableDurationFormatter.Render — string.Create+stackalloc on .NET 8+ (3–4 allocations → 1 per call) — Review
• Review PR perf-assist/progress-frame-reuse: Eliminate per-tick AnsiTerminalTestProgressFrame + RenderedLines allocations via double-buffer swap (~1 500 + ~1 500 allocs/5-min run) — PRs

Performance Opportunities Backlog

1. AnsiTerminalTestProgressFrame double-buffering — ✅ DONE (perf-assist/progress-frame-reuse, submitted 2026-06-06)
2. GenerateLinesToRender List<object> boxing — mixed TestProgressState/TestDetailState with is checks; consider sealed base type; higher complexity
3. GenerateLinesToRender per-frame array allocs — new TestProgressState[itemCount], new int[N], new List<TestDetailState>[N] — could be pooled/reused

Discovered Commands

• Build: ./build.sh -build -c Debug (Linux) / .\build.cmd -build -c Debug (Windows)
• Full build (all TFMs): ./build.sh (no flags)
• Run unit tests: artifacts/bin/Microsoft.Testing.Platform.UnitTests/Debug/net8.0/Microsoft.Testing.Platform.UnitTests
• dotnet binary: system dotnet is a stub; build.sh installs pinned SDK into .dotnet/

Run History

2026-06-06 14:09 UTC - Run

• 🔧 Task 4: PR [perf-improver] perf: fast path in HumanReadableDurationFormatter.Render for sub-hour durations #8861 checked — all CI green, no action needed
• 🔧 Task 3: Implemented double-buffer swap in AnsiTerminalTestProgressFrame/AnsiTerminal.RenderProgress (PR perf-assist/progress-frame-reuse) — ~3 000 fewer GC objects/5-min run
• 📊 Measured: 1086 passed, 0 failed unit tests after change

2026-06-05 14:22 UTC - Run

• 🔧 Task 3: Created PR [perf-improver] perf: fast path in HumanReadableDurationFormatter.Render for sub-hour durations #8861 — fast path in HumanReadableDurationFormatter.Render (3–4 allocs → 1)
• 💬 Task 5: Checked performance issues, no new actionable opportunities found
• 🔄 Task 4: PR [perf-improver] perf: single-pass message iteration in VSTestBridge ObjectModelConverters #8823 merged ✅

2026-06-04 - Run

• 🔄 Task 4: Checked open PRs for CI failures
• 🔍 Task 2: Identified HumanReadableDurationFormatter opportunity

2026-06-03 - [Older runs]

• 🔧 PR [perf-improver] perf: eliminate LINQ allocations in terminal progress render hot path #8799 merged: LINQ allocations in terminal progress render hot path ✅
• 🔧 PR [perf-improver] perf: single-pass message iteration in VSTestBridge ObjectModelConverters #8823 submitted: VSTestBridge single-pass message iteration

Earlier runs

• PR [perf-improver] perf: eliminate string allocations in ANSI render hot path #8769 merged: ANSI render hot path string allocs ✅
• PR [perf-improver] perf: eliminate per-call string allocation in AnsiTerminal.SetColor and use HashSet for KnownFileExtensions #8739 merged: AnsiTerminal.SetColor allocs + KnownFileExtensions HashSet ✅
• PR [perf-improver] perf: cache distinct processors in AsynchronousMessageBus to eliminate per-drain allocation #8704 merged: AsynchronousMessageBus drain dict → cached arrays ✅
• PR [perf-improver] perf: replace Regex array in AnsiDetector with direct string comparisons #8683 merged: AnsiDetector regex → direct string comparisons ✅

Generated by Perf Improver · sonnet46 5.8M · ◷

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