[Perf Improver] Monthly Activity 2026-05

[Evangelink]

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Activity for May 2026

Suggested Actions for Maintainer

• Review and apply patch from Run 25321208683: perf: eliminate LINQ allocations in IsIgnored hot path — download agent artifact and apply patch. Closes [Perf Improver] perf: eliminate LINQ allocations in IsIgnored hot path #7992, [Perf Improver] perf: eliminate LINQ allocations in IsIgnored hot path #7993, and [Perf Improver] perf: eliminate LINQ allocations in IsIgnored hot path #8000.
• Close issue [Perf Improver] perf: eliminate LINQ allocations in IsIgnored hot path #7992: Duplicate placeholder — superseded by patch in run 25321208683
• Close issue [Perf Improver] perf: eliminate LINQ allocations in IsIgnored hot path #7993: Duplicate placeholder — superseded by patch in run 25321208683
• Close issue [Perf Improver] perf: eliminate LINQ allocations in IsIgnored hot path #8000: Duplicate placeholder — superseded by patch in run 25321208683
• Close issue [Perf Improver] perf: reduce allocations in test discovery and data-driven test execution #7815: Changes (ValidSourceExtensions cache + ReflectionTestMethodInfo dedup) confirmed applied to main - View
• Close issue [Perf Improver] perf: avoid yield iterator allocations in test execution hot path #7904: Maintainers confirmed allocations not visible in profiler traces; branch can be discarded - View

(If no actions needed, state "No suggested actions at this time.")

Performance Opportunities Backlog

1. [Applied to main ✅] ValidSourceExtensions static cache + ReflectionTestMethodInfo deduplication
2. [Applied to main ✅] Eliminate LINQ iterator allocations in TryUnfoldITestDataSources
3. [Merged ✅ PR [Perf Improver] perf: eliminate LINQ iterator allocations in GetTestCategories and GetTestFromMethod #7927] Eliminate LINQ iterators in GetTestCategories + WorkItemAttribute double-pass + parameterless method short-circuit (~7 iterator objects per test method discovery)
4. [Deprioritized - no profiler evidence] Avoid yield iterator in TryExecuteDataSourceBasedTestsAsync + GetRetryAttribute (issue [Perf Improver] perf: avoid yield iterator allocations in test execution hot path #7904)
5. [Patch ready 🔧] Eliminate LINQ allocations in IsIgnored (~4 objects per test execution) — patch in run 25321208683 artifact
6. [Proposed - infrastructure] Add BenchmarkDotNet micro-benchmark project for discovery/execution hot paths — enables cross-platform allocation measurement
7. TreeNodeFilter LINQ closure allocations — covered by Efficiency Improver ([Efficiency Improver] perf: eliminate LINQ closure allocations in TreeNodeFilter.MatchFilterPattern and MatchProperties #7947, [Efficiency Improver] perf: eliminate LINQ closure allocations in TreeNodeFilter hot paths #7974)
8. SynchronizedStringBuilder in TestContextImplementation uses [MethodImpl(Synchronized)]; requires profiler evidence before implementing

Discovered Commands

• Build (Linux/macOS): export PATH="$PWD/.dotnet:$PATH" && dotnet restore && dotnet build -f net8.0
• Pre-existing infrastructure issue: MSTest.TestAdapter.csproj build fails due to missing ApplicationInsights NuGet (unrelated to test framework code)
• Targeting packs available: net8.0, net9.0 (after restore); net462/NETFRAMEWORK not available in sandbox

Run History

2026-05-04 13:22 UTC - Run

• 🔧 Task 3: Re-implemented IsIgnored LINQ allocation elimination (3rd attempt — previous branches deleted from remote). Fast path: 0 allocations for common case (no ConditionBaseAttribute). Build: 0 warnings, 0 errors. Patch in artifact.
• 🔍 Task 2: Investigated new opportunities — TestMethodInfo.GetAttributes<T>() copies cached array via yield; would need profiler evidence. No high-confidence new targets found.
• 📋 Task 7: Updated monthly activity summary

2026-05-03 13:18 UTC - Run

• 🔧 Task 3/4: Re-implemented IsIgnored LINQ allocation optimization (previous branch was deleted from remote). Fast path: 0 allocations for common case (no ConditionBaseAttribute). Build: 0 warnings, 0 errors. Patch available in run artifact.
• 📋 Task 7: Updated monthly activity summary

2026-05-02 13:19 UTC - Run

• 🔧 Task 3: Implemented IsIgnored LINQ allocation optimization — eliminates yield iterator + GroupBy operator (2+ objects) per call, called 2× per test execution. Created issues [Perf Improver] perf: eliminate LINQ allocations in IsIgnored hot path #7992 and [Perf Improver] perf: eliminate LINQ allocations in IsIgnored hot path #7993 as placeholders (PR creation restricted).
• 📋 Task 7: Updated monthly activity summary

2026-05-01 13:20 UTC - Run

• ✅ Task 4: PR [Perf Improver] perf: eliminate LINQ iterator allocations in GetTestCategories and GetTestFromMethod #7927 confirmed merged by Evangelink on 2026-04-30 — no open Perf Improver PRs
• 🔍 Task 2: Explored new opportunities — SynchronizedStringBuilder lock overhead identified but needs profiler evidence; TreeNodeFilter covered by Efficiency Improver
• 📋 Task 7: Closed April 2026 monthly issue; opened May 2026 monthly issue

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