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[efficiency-improver] Monthly Activity 2026-10

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
20/100
Issue type
Refactor
Clarity
Needs clarification
Activity status
Active
Tech stack
csharp, github-actions
Domain
testing-qa, tooling

Research direction

This is an automated monthly tracker rather than a single implementation task; first review the listed candidate areas and cross-check performance backlog issue #10914. The issue names possible files and build/test commands, but it does not define one change, acceptance criteria, or a specific test demonstrating completion.

Written by the indexing model from the issue text.

Description

area/performance type/automation

Activity for October 2026

Suggested Actions for Maintainer

No suggested actions at this time.

Energy Efficiency Backlog

Priority Focus Area Opportunity Estimated Impact
LOW Code-Level TestExecutionManager MethodLevel parallel array-per-test in setup One-time setup cost
LOW-MEDIUM Code-Level RuntimeRegistrationEmitter.EmitResolveMethodHelper/ResolveProperty (source generator): O(N×M) linear scan per test method at module-init One-time per-assembly startup cost, not a hot loop; re-examined 2026-10-13, still not worth changing
LOW Code-Level VideoProduction.cs ProducePerTestVideosAsync O(tests×segments) overlap scan Runs once at end-of-run (cold path)
LOW Test Infra test/Utilities/Microsoft.Testing.TestInfrastructure: regex-on-error-retry, tiny-collection LINQ Cold/low-frequency, negligible scale
LOW Code-Level MSTestTelemetryDataCollector.SerializeCollection/SerializeDictionary: OrderBy on telemetry flush Once per session (cold path)
LOW Code-Level TestClassModelBuilder (source generator): Where/GroupBy/Select for duplicate-method detection Compile-time only, not a runtime hot path
LOW Code-Level src/Adapter/MSTest.TestAdapter: reflection-based GetRuntimeMethod lookup in TestMethodFilter (cold, once per discovery context) Negligible, cold path
LOW Code-Level WindowTest.WindowSetup (MSTest.Windows.UIAutomation): fixed 50ms poll interval for window discovery, no exponential backoff Bounded by 10s timeout, once per test class (cold path); no measurement story in this sandbox (Windows-only)
LOW Code-Level TestDataConnectionSql.Names.cs SplitName/FindIdentifierEnd (NETFRAMEWORK-only legacy SQL/CSV/Excel table-name parsing): no caching across repeated calls Cold path, gated behind legacy net462 data-driven tests; re-examined 2026-10-13, still not worth changing
LOW Infrastructure CI output-byte-count health metric Needs maintainer discussion
LOW-MEDIUM Code-Level Executable-condition analyzer (#10634) recursive tree walk not memoized Gated behind narrow guards, single if-statement match per test method (cold/compile-time path), not urgent

Repo continues to be actively self-optimized by maintainers/Copilot coding agent. This run reviewed 10 commits landed since the previous run (2026-10-13T21:46Z): "Update .NET runtimes to latest versions" (#11927, dependency/TFM bump, no logic change); "[code-simplifier] Deduplicate failure-result construction in TestHostControllersTestHost" (#11931) — pure structural dedup (local function extraction for 4 duplicated failure-result tuples), no behavior or allocation-shape change, confirmed via full diff; "Prepare gated Linux/macOS affected-test collection" (#11930) and "Isolate affected-test collection from Windows validation" (#11926) — CI workflow-only; "Split MtpServerClient into focused partial files" (#11919) — pure file reorganization of the new ServerMode client library (Capabilities/Execution/Notifications partials), reviewed the full implementation for per-test-result/per-notification hot-path inefficiencies (JSON dictionary parsing, test-node building, response normalization) and found none — allocations are proportional to genuinely necessary payload data (one MtpTestNodeUpdate/MtpAttachment per actual test-node change), TryGetValue used correctly throughout with no repeated lookups; "Inventory all mutation-testing projects and onboard uncovered modules" (#11912) — CI/tooling infra only; remaining commits were OneLoc/dependency/doc updates. Delegated a focused fresh-code scan of src/Package/MSTest.Sdk, src/TestFramework/TestFramework.Extensions (non-PrivateObject areas), the new ServerMode.Client.Sources client library, and src/Platform/Microsoft.Testing.Platform/Hosts for new orchestrator code — 0 new HIGH/MEDIUM findings; TestHostOrchestratorHost.RunAsync confirmed one-time per-session cold path, RuntimeTypeHelper's nested-loop reflection is #if NETFRAMEWORK-gated legacy-only fallback already out of scope. 0 new HIGH/MEDIUM findings. Re-verified 0 open [efficiency-improver] PRs and re-checked #8824/#3495 for new human comments (none since 2026-07-14 and 2026-07-30 respectively) — not re-engaged per anti-spam policy. A broadened search for open performance/efficiency/energy/green software issues returned only the two already-tracked issues plus this tracker; all historically-filed [Efficiency Improver] perf: issues from May/August 2026 remain stale with no new activity.

Discovered Commands

Command Purpose
./build.sh Full restore + build (installs SDK to .dotnet/ first)
./build.sh -test Run unit tests
./build.sh -pack Build + produce NuGet packages
./build.sh -pack -test -integrationTest Full pipeline incl. acceptance tests
.dotnet/dotnet build <proj>.csproj -c Debug -f <tfm> Build a single project directly once SDK is bootstrapped
artifacts/bin/<Project>/Debug/<tfm>/<Assembly> (run directly) Run a built test-host binary — more reliable than dotnet test/dotnet run --project in this sandbox for filter flags
<host> --filter "FullyQualifiedName~Name" vstest-style substring filter that works reliably against a built MTP test host in this sandbox
dotnet format whitespace TestFx.slnx --verify-no-changes --include <file> Format verification (needs explicit TestFx.slnx workspace arg)

Notes: repo-local SDK at .dotnet/dotnet (Arcade-provisioned, must bootstrap via ./build.sh first, ~5-6 min first time). Some internal classes are tracked by the PublicAPI analyzer via a separate InternalAPI/InternalAPI.Shipped.txt+.Unshipped.txt pair (distinct from PublicAPI/) for cross-assembly InternalsVisibleTo tests — this also applies to default-value changes on an already-shipped internal signature, not just full signature changes. Partial-TFM dotnet restore -p:TargetFramework(s)=net8.0 workaround corrupts sibling projects' project.assets.json — avoid; skip net462/net48-only test projects in this sandbox instead and document the gap.

Run History

2026-10-14 21:48 UTC - Run
  • 🔍 Confirmed 0 open [efficiency-improver] PRs.
  • 🔍 Reviewed 10 commits landed since 2026-10-13: #11927 (dependency/TFM bump), #11931 (pure structural dedup of failure-result construction, no behavior change), #11930/#11926 (CI workflow-only), #11919 (new ServerMode client library split into partial files — reviewed full implementation, no hot-path inefficiencies found, allocations proportional to necessary payload), #11912 (mutation-testing CI infra), plus OneLoc/dependency commits.
  • 🔍 Delegated a fresh-code scan of src/Package/MSTest.Sdk, src/TestFramework/TestFramework.Extensions, the new ServerMode.Client.Sources library, and src/Platform/Microsoft.Testing.Platform/Hosts — 0 new HIGH/MEDIUM findings, all either cold-path/one-time or allocation proportional to real output.
  • 💬 Re-checked #8824/#3495 — no new human comments since last review; not re-engaged (anti-spam holds). Broadened search confirms no new efficiency/performance/energy/green-software-labeled issues; stale May/August 2026 [Efficiency Improver] perf: issues remain untouched.
  • No PR created this run (nothing new to measure).
2026-10-13 21:46 UTC - Run
  • 🔍 Confirmed 0 open [efficiency-improver] PRs.
  • 🔍 Reviewed 8 commits landed since 2026-10-12: #11917 (test-value-evidence tooling), #11916 (coverage improvements; the one product file touched, EnvironmentVariables.cs, confirmed already correctly guarded with IsEnabled(LogLevel.Trace)), #11915 (affected-test-collection fix), #11906 (pure structural process-lifecycle file split), #11913 (test-only), plus OneLoc/dependency commits — none touching product hot paths.
  • 🔍 Re-examined 2 existing LOW backlog items (RuntimeRegistrationEmitter resolve helpers, TestDataConnectionSql.SplitName) for promotion — both remain cold-path/bounded, declined.
  • 🔍 0 new HIGH/MEDIUM findings this run.
  • 💬 Re-checked #8824/#3495 — no new human comments since last review; not re-engaged (anti-spam holds). Broadened issue search confirms no new efficiency/performance/energy/green-software-labeled issues beyond the two already tracked.
  • No PR created this run (nothing new to measure).
2026-10-12 21:46 UTC - Run
  • 🔍 Confirmed 0 open [efficiency-improver] PRs.
  • 🔍 Reviewed 18 commits landed since 2026-10-11: #11896 (headless-Windows JSON-escaping correctness fix, cold discovery path), #11892 (new MSTEST0090 performance-advisory analyzer, already efficiently implemented), plus CI/tooling, test-coverage-only, and docs/dependency commits — none touching product hot paths.
  • 🔍 0 new HIGH/MEDIUM findings this run.
  • 💬 Re-checked #8824/#3495 — no new human comments since last review; not re-engaged (anti-spam holds). Broadened issue search confirms no new efficiency/performance/energy/green-software-labeled issues beyond the two already tracked.
  • No PR created this run (nothing new to measure).
2026-10-11 21:49 UTC - Run
  • 🔍 Confirmed 0 open [efficiency-improver] PRs.
  • 🔍 Reviewed commits landed since 2026-10-10: only 1 product-code change (PR #11867, TestHostControllersTestHost file split) — confirmed via full diff review this is a pure structural refactor of cold-path process-lifecycle code (event-driven cancellation, once-per-session finalization), no hot loop, no efficiency opportunity.
  • 🔍 0 new HIGH/MEDIUM findings this run.
  • 💬 Re-checked #8824/#3495 — no new human comments; not re-engaged (anti-spam holds).
  • No PR created this run.
2026-10-10 21:45 UTC - Run
  • 🔍 Confirmed zero new commits on main since the 2026-10-09 run — genuinely idle window.
  • 🔍 Confirmed 0 open [efficiency-improver] PRs.
  • 💬 Re-checked #8824/#3495 — no new human comments; not re-engaged.
  • No PR created this run.

🤖 Automated content by GitHub Copilot. Generated by the Efficiency Improver workflow. · copilot · auto · 188.8 AIC · ⌖ 15.2 AIC · ⊞ 21.6K · [◷]( · ◷)

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