[perf-improver] Monthly Activity 2026-09

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#10,914 opened on Sep 1, 2026 0 comments 0 reactions 0 assignees View on GitHub

area/performance type/automation

Dominant language: C#
Stars: 1k
Forks: 312
Avg merge: 8h 30m
Merged PRs (30d): 469

Description

## Activity for September 2026

## Suggested Actions for Maintainer

No suggested actions at this time.

## Performance Opportunities Backlog

- PrivateObject.Helpers.cs generic-method cache (net-fx only) - low priority
- TestExecutionManager.ParallelExecution.cs per-test array wrapping - inherent design, low priority
- AggregatedConfiguration indexer scan - low impact
- ServerTestHost.RequestExecution.cs Select+ToArray - per-request not per-test, low impact
- RetryArtifactProcessor.cs GroupBy/Count double-enumeration - low volume, low priority
- RetryOrchestrator.ArtifactRecovery.cs Any() per-manifest-line - low volume, low priority

## Discovered Commands

- Build (Debug): `./build.sh`
- Build (Release): `./build.sh -c Release`
- Pack (NuGet packages, required for acceptance/integration tests): `./build.sh -pack`
- Unit tests: `./build.sh -test`
- Integration + acceptance tests: `./build.sh -pack -test -integrationTest`
- Note: net462/net48-targeting unit test projects (e.g. `MSTestAdapter.PlatformServices.UnitTests`, `MSTestAdapter.UnitTests`) cannot be built/run standalone on this Linux sandbox (no .NET Framework SDK); TargetFrameworks cannot be restricted via `-p:` CLI override for these multi-targeted projects.

## Run History

### 2026-09-08 13:37 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 💬 PR #11084 (NUL-escape allocation "fix" from prior run) was closed by maintainer: verified `string.Replace` doesn't allocate on no-match even on .NET Framework 4.8, so the change was a net regression (redundant scan). Lesson recorded in memory.
- 🔍 Scanned Execution remainder, Platform Services/Capabilities, CollectionAssert.Equivalence/Subset, Deployment utilities - no new actionable hot-path findings
- 📊 No open perf-improver PRs or performance-labeled issues remain

### 2026-09-07 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Identified opportunity: unconditional NUL-escape allocation in `TestContextImplementation.Output.cs` Write/WriteLine (allocates on netstandard2.0/net462 even with no NUL char present)
- 🔧 Created PR: Avoid unconditional NUL-escape allocation in TestContext.Write/WriteLine (branch `perf-assist/testcontext-output-escapenul`) — later closed, see 2026-09-08 entry
- 📊 Measured: microbenchmark confirms 0 allocations either way on net9.0 (already has Replace fast path); netstandard2.0/net462 benefit claim was later disproven by maintainer

### 2026-09-06 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned MSTest.Sdk, TestFramework/Attributes, remaining PlatformServices/Services files, Platform TestHost dispatch - no new hot-path findings
- 💬 No open performance-labeled issues; no open perf-improver PRs

### 2026-09-05 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned MSTest.TestAdapter/Discovery, Platform Hosts/Services, Assertions, Logging - one candidate (FrameworkHandlerAdapter.cs interpolation) investigated and confirmed false positive (compiler constant-folds nameof-only interpolations)

### 2026-09-03 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned MSTest.TestAdapter/Discovery remainder, Platform Logging internals, CrashDump/HangDump internals, TrxReport/AzureDevOpsReport internals, TestFramework.Extensions DataRow/DynamicData resolver chain, Analyzers fixers - no new hot-path findings> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34232585148/agentic_workflow) workflow. · auto · 106.4 AIC · ⌖ 2.33 AIC · ⊞ 18.8K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
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---

## Activity for September 2026

## Suggested Actions for Maintainer

No suggested actions at this time.

## Performance Opportunities Backlog

## Discovered Commands

## Run History

### 2026-09-09 13:39 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34357735119)
- 🔍 Scanned HotReload extension, remaining Telemetry files, TrxReport (non-Abstractions), AzureDevOpsReport internals, VSTestBridge remainder - no new actionable hot-path findings; codebase remains extensively optimized from prior passes
- 📊 No open perf-improver PRs or performance-labeled issues remain

### 2026-09-04 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned Execution (TestMethodInfo/TestClassInfo/TestMethodRunner), Platform Framework host loop, Messages, TestFramework Assertions - no new hot-path findings> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34357735119/agentic_workflow) workflow. · auto · 95.3 AIC · ⌖ 3.27 AIC · ⊞ 15.9K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
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_{Add this agentic workflow to your repo}

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---

## Activity for September 2026

## Suggested Actions for Maintainer

No suggested actions at this time.

## Performance Opportunities Backlog

1. `PrivateObject.Helpers.cs BuildGenericMethodCacheForType` (net-framework-only): rebuilds cache per `PrivateObject` instance construction, not cached across instances of the same type. Medium risk (touches internal representation), low priority.
2. `TestExecutionManager.ParallelExecution.cs`: wraps each single test element into a new array per test when building parallel scheduling chunks. Inherent to the chunk-representation contract; medium risk/effort to redesign.
3. `AggregatedConfiguration` indexer scan: linear provider scan per config lookup, results already memoized. Low impact.
4. `ServerTestHost.RequestExecution.cs`: `.Select().ToArray()` on test nodes, once per run request (not per-test). Low impact.
5. `RetryArtifactProcessor.cs`: `GroupBy`/`Any(Count())` double-enumeration, only matters with many retries+artifacts. Low volume.
6. `RetryOrchestrator.ArtifactRecovery.cs`: `Any()` per-manifest-line. Low volume.
7. `InheritedMemberFromDifferentMSTestVersionAnalyzer.GetFrameworkAssembly`/`IsGloballyVisibleReference`: LINQ chain over `GetAttributes()` and `compilation.References.Any(...)` scan run for every named-type symbol in a compilation (IDE/build hot path in the analyzer sense), before cheaper early-out checks. Low confidence this is measurably costly (collections involved are small; empty-attribute classes short-circuit), not prioritized without profiling evidence.

Codebase remains thoroughly optimized after ~6 weeks of near-daily scans across virtually every module (Platform, Adapter, TestFramework, Analyzers, Extensions). Backlog items above are all low-priority/low-confidence; several are inherent to design and considered won't-fix without a larger redesign.

## Discovered Commands

```sh
./build.sh # restore + build (Debug)
./build.sh -test # build + unit tests
./build.sh -pack # produce NuGet packages
./build.sh -pack -test -integrationTest # full suite (slow)
```
Note: MSTestAdapter.UnitTests and other net48-targeting tests can't run standalone in this Linux sandbox (no .NET Framework SDK); full `./build.sh -test` is the reliable path.

## Run History

### 2026-09-10 13:33 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34483050997)
- 🔍 Scanned MSTest.Analyzers (analyzers + fixers) and Discovery remaining files for fresh hot-path candidates - no high-confidence new findings; one low-confidence marginal item noted (InheritedMemberFromDifferentMSTestVersionAnalyzer.GetFrameworkAssembly LINQ chain runs per named-type symbol)
- No open perf-improver PRs, no performance-labeled issues this run

### 2026-09-09 - [Run](https://github.com/microsoft/testfx/actions/runs/34357735119)
- 🔍 Scanned HotReload, Telemetry, TrxReport, AzureDevOpsReport, MSTest.Sdk, VSTestBridge - no new hot-path findings

### 2026-09-08 - [Run](https://github.com/microsoft/testfx/actions/runs/34357735119)
- 📊 PR #11084 closed by maintainer (Replace no-match optimization already exists on all TFMs - false premise, lesson recorded)
- 🔍 Scanned Execution remaining files, Services/Capabilities, CollectionAssert internals, Deployment - no new hot-path findings

### 2026-09-07 - [Run](https://github.com/microsoft/testfx/actions/runs/34357735119)
- 🔧 Created PR #11084: Avoid unconditional NUL-escape allocation in TestContext.Write/WriteLine (later closed, see 2026-09-08)

### 2026-09-06 - [Run](https://github.com/microsoft/testfx/actions/runs/34357735119)
- 🔍 Scanned MSTest.Sdk, TestFramework/Attributes, PlatformServices remaining files, Platform TestHost dispatch - no new hot-path findings

### 2026-09-04 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned Execution (TestMethodInfo/TestClassInfo/TestMethodRunner), Platform Framework host loop, Messages, TestFramework Assertions - no new hot-path findings> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34483050997/agentic_workflow) workflow. · auto · 92 AIC · ⌖ 2.31 AIC · ⊞ 15.9K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
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---

## Activity for September 2026

## Suggested Actions for Maintainer

No suggested actions at this time.

## Performance Opportunities Backlog

1. `PrivateObject.Helpers.cs BuildGenericMethodCacheForType` (net-framework-only): rebuilds cache per `PrivateObject` instance construction, not cached across instances of the same type. Medium risk (touches internal representation), low priority.
2. `TestExecutionManager.ParallelExecution.cs`: wraps each single test element into a new array per test when building parallel scheduling chunks. Inherent to the chunk-representation contract; medium risk/effort to redesign.
3. `AggregatedConfiguration` indexer scan: linear provider scan per config lookup, results already memoized. Low impact.
4. `ServerTestHost.RequestExecution.cs`: `.Select().ToArray()` on test nodes, once per run request (not per-test). Low impact.
5. `RetryArtifactProcessor.cs`: `GroupBy`/`Any(Count())` double-enumeration, only matters with many retries+artifacts. Low volume.
6. `RetryOrchestrator.ArtifactRecovery.cs`: `Any()` per-manifest-line. Low volume.
7. `InheritedMemberFromDifferentMSTestVersionAnalyzer.GetFrameworkAssembly`/`IsGloballyVisibleReference`: LINQ chain over `GetAttributes()` and `compilation.References.Any(...)` scan run for every named-type symbol in a compilation, before cheaper early-out checks. Low confidence this is measurably costly without profiling.

Codebase remains thoroughly optimized after ~6.5 weeks of near-daily scans across virtually every module (Platform, Adapter, TestFramework, Analyzers, Extensions). Backlog items above are all low-priority/low-confidence; several are inherent to design and considered won't-fix without a larger redesign.

## Discovered Commands

```sh
./build.sh # restore + build (Debug)
./build.sh -test # build + unit tests
./build.sh -pack # produce NuGet packages
./build.sh -pack -test -integrationTest # full suite (slow)
```
Note: MSTestAdapter.UnitTests and other net48-targeting tests can't run standalone in this Linux sandbox (no .NET Framework SDK); full `./build.sh -test` is the reliable path.

## Run History

### 2026-09-11 13:33 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34604797665)
- 🔍 Scanned MSTest.Analyzers.CodeFixes (all fixers), HtmlReport extension (BuildJson/Merger), MSTestAdapter.PlatformServices/Services remaining files, Platform/Extensions remaining files - no new hot-path findings; all reviewed code is cold/IDE-invoked/once-per-run
- 📊 No open perf-improver PRs, no performance-labeled issues this run

### 2026-09-10 - [Run](https://github.com/microsoft/testfx/actions/runs/34483050997)
- 🔍 Scanned MSTest.Analyzers (analyzers + fixers) and Discovery remaining files for fresh hot-path candidates - no high-confidence new findings; one low-confidence marginal item noted (InheritedMemberFromDifferentMSTestVersionAnalyzer.GetFrameworkAssembly LINQ chain runs per named-type symbol)

### 2026-09-08 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 📊 PR #11084 closed by maintainer (Replace no-match optimization already exists on all TFMs - false premise, lesson recorded)
- 🔍 Scanned Execution remaining files, Services/Capabilities, CollectionAssert internals, Deployment - no new hot-path findings

### 2026-09-07 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔧 Created PR #11084: Avoid unconditional NUL-escape allocation in TestContext.Write/WriteLine (later closed, see 2026-09-08)

### 2026-09-06 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned MSTest.Sdk, TestFramework/Attributes, PlatformServices remaining files, Platform TestHost dispatch - no new hot-path findings

### 2026-09-04 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned Execution (TestMethodInfo/TestClassInfo/TestMethodRunner), Platform Framework host loop, Messages, TestFramework Assertions - no new hot-path findings> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34604797665/agentic_workflow) workflow. · auto · 79.9 AIC · ⌖ 2.98 AIC · ⊞ 15.9K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

* [ ] **Review PR**: "Reorder cheap checks before GetFrameworkAssembly in InheritedMemberFromDifferentMSTestVersionAnalyzer" (branch `perf-assist/analyzer-reorder-checks`, opened this run)

## Performance Opportunities Backlog

- PrivateObject.Helpers.cs generic-method cache (net-fx only) - low priority
- TestExecutionManager.ParallelExecution.cs per-test array wrapping - inherent design, low priority
- AggregatedConfiguration indexer scan - low impact (real inefficiency but consumers already cache results, not a hot path in practice)
- ServerTestHost.RequestExecution.cs Select+ToArray - per-request not per-test, low impact
- RetryArtifactProcessor.cs GroupBy/Count double-enumeration - low volume, low priority
- RetryOrchestrator.ArtifactRecovery.cs Any() per-manifest-line - low volume, low priority

## Discovered Commands

## Run History

### 2026-09-12 13:31 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34696563755)
- 🔍 Identified opportunity: `InheritedMemberFromDifferentMSTestVersionAnalyzer.AnalyzeSymbol` calls `GetFrameworkAssembly` (LINQ attribute-walk + `compilation.References.Any()` scan) before cheap structural checks (abstract/generic/visibility/TestContext-signature) that reject most named-type symbols
- 🔧 Created PR: Reorder cheap checks before GetFrameworkAssembly in InheritedMemberFromDifferentMSTestVersionAnalyzer
- 📊 Measured: standalone Roslyn microbenchmark (20k synthetic types) — 205ms → 174ms over 20 iterations (~18% faster), identical match counts confirming no behavior change

### 2026-09-11 13:33 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34604797665)
- 🔍 Scanned MSTest.Analyzers.CodeFixes (all fixers), HtmlReport extension, MSTestAdapter.PlatformServices/Services remaining files, Platform/Extensions remaining files - no new hot-path findings; all reviewed code is cold/IDE-invoked/once-per-run
- 📊 No open perf-improver PRs, no performance-labeled issues this run

### 2026-09-10 - [Run](https://github.com/microsoft/testfx/actions/runs/34483050997)
- 🔍 Scanned MSTest.Analyzers (analyzers + fixers) and Discovery remaining files for fresh hot-path candidates - one low-confidence marginal item noted (later confirmed and fixed 2026-09-12)

### 2026-09-04 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned Execution (TestMethodInfo/TestClassInfo/TestMethodRunner), Platform Framework host loop, Messages, TestFramework Assertions - no new hot-path findings> [!WARNING]
>
> Firewall blocked 1 domain
>
> The following domain was blocked by the firewall during workflow execution:
>
> - `southcentralus0.in.applicationinsights.azure.com`
>
> To allow these domains, add them to the `network.allowed` list in your workflow frontmatter:
>
> ```yaml
> network:
> allowed:
> - defaults
> - "southcentralus0.in.applicationinsights.azure.com"
> ```
>
> See [Network Configuration](https://github.github.com/gh-aw/reference/network/) for more information.
>
>

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34696563755/agentic_workflow) workflow. · auto · 186.4 AIC · ⌖ 13.3 AIC · ⊞ 15.9K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
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To install this agentic workflow, run

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```

---

## Activity for September 2026

## Suggested Actions for Maintainer

* [ ] **Review PR**: "[perf-improver] Add benchmark coverage for TelemetryCollector.TrackAssertionCall" (branch perf-assist/telemetrycollector-benchmark) - adds reproducible benchmark for the assertion-tracking hot path - [Review](https://github.com/microsoft/testfx/pulls?q=is:pr+head:perf-assist%2Ftelemetrycollector-benchmark)

## Performance Opportunities Backlog

- PrivateObject.Helpers.cs generic-method cache (net-fx only) - low priority
- TestExecutionManager.ParallelExecution.cs per-test array wrapping - inherent design, low priority
- AggregatedConfiguration indexer scan - low impact (re-verified 2026-09-13: downstream consumers cache via static MSTestSettings.CurrentSettings singleton, confirmed no per-test hot-path bug)
- ServerTestHost.RequestExecution.cs Select+ToArray - per-request not per-test, low impact
- RetryArtifactProcessor.cs GroupBy/Count double-enumeration - low volume, low priority
- RetryOrchestrator.ArtifactRecovery.cs Any() per-manifest-line - low volume, low priority

## Discovered Commands

- Build (Debug): `./build.sh`
- Build (Release): `./build.sh -c Release`
- Pack (NuGet packages, required for acceptance/integration tests): `./build.sh -pack`
- Unit tests: `./build.sh -test`
- Integration + acceptance tests: `./build.sh -pack -test -integrationTest`
- Benchmarks: `dotnet run --project test/Performance/MSTest.Performance.Benchmarks -c Release --no-build -- --filter "**" --job short`
- Note: net462/net48-targeting unit test projects (e.g. `MSTestAdapter.PlatformServices.UnitTests`, `MSTestAdapter.UnitTests`) cannot be built/run standalone on this Linux sandbox (no .NET Framework SDK); TargetFrameworks cannot be restricted via `-p:` CLI override for these multi-targeted projects.

## Run History

### 2026-09-13 13:31 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34759985386)
- 🔍 Scanned MSTest.Analyzers (non-CodeFixes), Retry extension internals, MSTest.Sdk build files, AggregatedConfiguration/MSTestSettings caching - no new actionable hot-path findings; confirmed AggregatedConfiguration caching claim from prior runs is accurate
- 🔧 Created PR: Add benchmark coverage for TelemetryCollector.TrackAssertionCall (branch perf-assist/telemetrycollector-benchmark) - measurement infrastructure, no production code changed
- 📊 Measured: TrackAssertionCall single-threaded 10.62ns/0B, disabled 0.37ns/0B, 4-thread contended 543.7μs for 4000 calls (~136ns/op), confirming the prior contention-reduction optimization remains allocation-free

### 2026-09-12 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 🔧 Created PR: Reorder cheap checks before GetFrameworkAssembly in InheritedMemberFromDifferentMSTestVersionAnalyzer (~18% faster on synthetic 20k-type benchmark)
- 🔍 Scanned Retry internals, MSTest.Sdk MSBuild task source, AggregatedConfiguration re-check

### 2026-09-11 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 🔍 Scanned MSTest.Analyzers.CodeFixes, HtmlReport extension, MSTestAdapter.PlatformServices remaining files, Platform/Extensions remaining files - no new hot-path findings

### 2026-09-10 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 🔍 Scanned MSTest.Analyzers + MSTestAdapter.PlatformServices/Discovery remaining files - found low-confidence analyzer LINQ-ordering candidate (later fixed 2026-09-12)

### 2026-09-09 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 🔍 Scanned HotReload, Telemetry remaining files, TrxReport, AzureDevOpsReport internals, VSTestBridge remaining files - no new hot-path findings

### 2026-09-03 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned MSTest.TestAdapter/Discovery remainder, Platform Logging internals, CrashDump/HangDump internals, TrxReport/AzureDevOpsReport internals, TestFramework.Extensions DataRow/DynamicData resolver chain, Analyzers fixers - no new hot-path findings> [!WARNING]
>
> Firewall blocked 1 domain
>
> The following domain was blocked by the firewall during workflow execution:
>
> - `southcentralus0.in.applicationinsights.azure.com`
>
> To allow these domains, add them to the `network.allowed` list in your workflow frontmatter:
>
> ```yaml
> network:
> allowed:
> - defaults
> - "southcentralus0.in.applicationinsights.azure.com"
> ```
>
> See [Network Configuration](https://github.github.com/gh-aw/reference/network/) for more information.
>
>

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34759985386/agentic_workflow) workflow. · auto · 184.6 AIC · ⌖ 18.9 AIC · ⊞ 15.9K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

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```

---

## Activity for September 2026

## Suggested Actions for Maintainer

No suggested actions at this time.

## Performance Opportunities Backlog

- PrivateObject.Helpers.cs generic-method cache (net-fx only) - low priority
- TestExecutionManager.ParallelExecution.cs per-test array wrapping - inherent design, low priority
- AggregatedConfiguration indexer scan - low impact, re-verified accurate
- ServerTestHost.RequestExecution.cs Select+ToArray - per-request not per-test, low priority
- RetryArtifactProcessor.cs GroupBy/Count double-enumeration - low volume, low priority
- RetryOrchestrator.ArtifactRecovery.cs Any() per-manifest-line - low volume, low priority

*(Backlog is very slim after ~7 weeks of near-daily scans; codebase is thoroughly optimized on hot paths.)*

## Discovered Commands

## Run History

### 2026-09-14 13:35 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- 🔄 Confirmed PRs #11225 (analyzer check reorder) and #11242 (TelemetryCollector benchmarks) merged by maintainer
- 🔍 Scanned Configurations, MSTestAdapter.PlatformServices Utilities, remaining Assert*.cs files, recent commits - no new findings
- 💬 No open performance-labeled issues, no open perf-improver PRs

### 2026-09-13 - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- 🔧 Created PR: Add benchmark coverage for TelemetryCollector.TrackAssertionCall
- 🔍 Re-verified AggregatedConfiguration/MSTestSettings caching claim - accurate, no bug

### 2026-09-12 - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- 🔧 Created PR: Reorder cheap checks before GetFrameworkAssembly in InheritedMemberFromDifferentMSTestVersionAnalyzer (~18% faster on synthetic benchmark)

### 2026-09-10 - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- 🔍 Scanned MSTest.Analyzers and Discovery remaining files - no hot-path issues; flagged analyzer LINQ chain as low-confidence candidate (later fixed 09-12)

### 2026-09-09 - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- 🔍 Scanned HotReload, Telemetry, TrxReport, AzureDevOpsReport, VSTestBridge remaining files - no new findings

### 2026-09-08 - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- ⚠️ PR #11084 (TestContext NUL-escape) closed by maintainer - underlying Replace() already zero-alloc on no-match across all TFMs, no fix needed

### 2026-09-07 - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- 🔧 Created PR: Avoid unconditional NUL-escape allocation in TestContext.Write/WriteLine (later found unnecessary, see 09-08)

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34849959068/agentic_workflow) workflow. · copilot · auto · 98.1 AIC · ⌖ 8.05 AIC · ⊞ 16.5K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
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>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

No suggested actions at this time.

## Performance Opportunities Backlog

- PrivateObject.Helpers.cs generic-method cache (net-fx only) - low priority
- TestExecutionManager.ParallelExecution.cs per-test array wrapping - inherent design, low priority
- AggregatedConfiguration indexer scan - low impact, re-verified accurate
- ServerTestHost.RequestExecution.cs Select+ToArray - per-request not per-test, low priority
- RetryArtifactProcessor.cs GroupBy/Count double-enumeration - low volume, low priority
- RetryOrchestrator.ArtifactRecovery.cs Any() per-manifest-line - low volume, low priority

*(Backlog remains very slim after ~8 weeks of near-daily scans; codebase is thoroughly optimized on hot paths.)*

## Discovered Commands

## Run History

### 2026-09-15 13:42 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34975663036)
- 🔍 Scanned Platform/Services, Platform/Messages+Requests, Platform/OutputDevice+Terminal, TestFramework CollectionAssert/StringAssert - no new hot-path findings, everything already optimized (dict-based, no LINQ in per-test paths)
- 💬 No open performance-labeled issues, no open perf-improver PRs, no new commits since last run
- 📊 Runtime hot-path scans have found nothing new for ~3 weeks across nearly every subsystem - next runs should shift weight toward Task 6 (measurement infrastructure)

### 2026-09-09 - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- 🔍 Scanned HotReload, Telemetry, TrxReport, AzureDevOpsReport, VSTestBridge remaining files - no new findings

### 2026-09-08 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- ⚠️ PR #11084 (TestContext NUL-escape) closed by maintainer - underlying Replace() already zero-alloc on no-match across all TFMs, no fix needed

### 2026-09-07 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 🔧 Created PR: Avoid unconditional NUL-escape allocation in TestContext.Write/WriteLine (later found unnecessary, see 09-08)

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34975663036/agentic_workflow) workflow. · copilot · auto · 108.2 AIC · ⌖ 7.04 AIC · ⊞ 16.5K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

## Performance Opportunities Backlog

## Discovered Commands

## Run History

### 2026-09-16 13:35 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/35102604382)
- 🔍 Reviewed prior run's suggestion (2026-09-15) to add benchmark coverage for CollectionAssert.Equivalence (no dedicated benchmark existed despite `$ CONSIDER` comments flagging the counting algorithm)
- 🔧 Created PR: "[perf-improver] Add benchmark coverage for CollectionAssert.AreEquivalent" (branch `perf-assist/collectionassert-equivalence-benchmark`) - new `CollectionAssertEquivalenceBenchmarks.cs`
- 📊 Measured: small (5-item) collection 693.6 ns / 1.32 KB; large (1000-item) collection 108.6 μs (156x) / 246.7 KB (187x) alloc - new baseline for future optimization
- ✅ `./build.sh -c Release` succeeded; `CollectionAssertTests` 54/54 passed
- 💬 No open perf-improver PRs before this run's new one; no open performance-labeled issues found

### 2026-09-03 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned MSTest.TestAdapter/Discovery remainder, Platform Logging internals, CrashDump/HangDump internals, TrxReport/AzureDevOpsReport internals, TestFramework.Extensions DataRow/DynamicData resolver chain, Analyzers fixers - no new hot-path findings> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34232585148/agentic_workflow) workflow. · auto · 106.4 AIC · ⌖ 2.33 AIC · ⊞ 18.8K · [◷]( · [◷](https://github.com/search?q=repo:microsoft%2Ftestfx+is:issue+%22gh-aw-workflow-call-id:+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

## Performance Opportunities Backlog

## Discovered Commands

## Run History

### 2026-09-04 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned Execution (TestMethodInfo/TestClassInfo/TestMethodRunner), Platform Framework host loop, Messages, TestFramework Assertions - no new hot-path findings> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34357735119/agentic_workflow) workflow. · auto · 95.3 AIC · ⌖ 3.27 AIC · ⊞ 15.9K · [◷]( · [◷](https://github.com/search?q=repo:microsoft%2Ftestfx+is:issue+%22gh-aw-workflow-call-id:+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

## Performance Opportunities Backlog

## Discovered Commands

```sh
./build.sh # restore + build (Debug)
./build.sh -test # build + unit tests
./build.sh -pack # produce NuGet packages
./build.sh -pack -test -integrationTest # full suite (slow)
```
Note: MSTestAdapter.UnitTests and other net48-targeting tests can't run standalone in this Linux sandbox (no .NET Framework SDK); full `./build.sh -test` is the reliable path.

## Run History

### 2026-09-04 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned Execution (TestMethodInfo/TestClassInfo/TestMethodRunner), Platform Framework host loop, Messages, TestFramework Assertions - no new hot-path findings> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34483050997/agentic_workflow) workflow. · auto · 92 AIC · ⌖ 2.31 AIC · ⊞ 15.9K · [◷]( · [◷](https://github.com/search?q=repo:microsoft%2Ftestfx+is:issue+%22gh-aw-workflow-call-id:+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

## Performance Opportunities Backlog

1. `PrivateObject.Helpers.cs BuildGenericMethodCacheForType` (net-framework-only): rebuilds cache per `PrivateObject` instance construction, not cached across instances of the same type. Medium risk (touches internal representation), low priority.
2. `TestExecutionManager.ParallelExecution.cs`: wraps each single test element into a new array per test when building parallel scheduling chunks. Inherent to the chunk-representation contract; medium risk/effort to redesign.
3. `AggregatedConfiguration` indexer scan: linear provider scan per config lookup, results already memoized. Low impact.
4. `ServerTestHost.RequestExecution.cs`: `.Select().ToArray()` on test nodes, once per run request (not per-test). Low impact.
5. `RetryArtifactProcessor.cs`: `GroupBy`/`Any(Count())` double-enumeration, only matters with many retries+artifacts. Low volume.
6. `RetryOrchestrator.ArtifactRecovery.cs`: `Any()` per-manifest-line. Low volume.
7. `InheritedMemberFromDifferentMSTestVersionAnalyzer.GetFrameworkAssembly`/`IsGloballyVisibleReference`: LINQ chain over `GetAttributes()` and `compilation.References.Any(...)` scan run for every named-type symbol in a compilation, before cheaper early-out checks. Low confidence this is measurably costly without profiling.

## Discovered Commands

```sh
./build.sh # restore + build (Debug)
./build.sh -test # build + unit tests
./build.sh -pack # produce NuGet packages
./build.sh -pack -test -integrationTest # full suite (slow)
```
Note: MSTestAdapter.UnitTests and other net48-targeting tests can't run standalone in this Linux sandbox (no .NET Framework SDK); full `./build.sh -test` is the reliable path.

## Run History

### 2026-09-04 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned Execution (TestMethodInfo/TestClassInfo/TestMethodRunner), Platform Framework host loop, Messages, TestFramework Assertions - no new hot-path findings> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34604797665/agentic_workflow) workflow. · auto · 79.9 AIC · ⌖ 2.98 AIC · ⊞ 15.9K · [◷]( · [◷](https://github.com/search?q=repo:microsoft%2Ftestfx+is:issue+%22gh-aw-workflow-call-id:+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

* [ ] **Review PR**: "Reorder cheap checks before GetFrameworkAssembly in InheritedMemberFromDifferentMSTestVersionAnalyzer" (branch `perf-assist/analyzer-reorder-checks`, opened this run)

## Performance Opportunities Backlog

- PrivateObject.Helpers.cs generic-method cache (net-fx only) - low priority
- TestExecutionManager.ParallelExecution.cs per-test array wrapping - inherent design, low priority
- AggregatedConfiguration indexer scan - low impact (real inefficiency but consumers already cache results, not a hot path in practice)
- ServerTestHost.RequestExecution.cs Select+ToArray - per-request not per-test, low impact
- RetryArtifactProcessor.cs GroupBy/Count double-enumeration - low volume, low priority
- RetryOrchestrator.ArtifactRecovery.cs Any() per-manifest-line - low volume, low priority

## Discovered Commands

## Run History

### 2026-09-11 13:33 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/34604797665)
- 🔍 Scanned MSTest.Analyzers.CodeFixes (all fixers), HtmlReport extension, MSTestAdapter.PlatformServices/Services remaining files, Platform/Extensions remaining files - no new hot-path findings; all reviewed code is cold/IDE-invoked/once-per-run
- 📊 No open perf-improver PRs, no performance-labeled issues this run

### 2026-09-10 - [Run](https://github.com/microsoft/testfx/actions/runs/34483050997)
- 🔍 Scanned MSTest.Analyzers (analyzers + fixers) and Discovery remaining files for fresh hot-path candidates - one low-confidence marginal item noted (later confirmed and fixed 2026-09-12)

### 2026-09-04 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned Execution (TestMethodInfo/TestClassInfo/TestMethodRunner), Platform Framework host loop, Messages, TestFramework Assertions - no new hot-path findings> [!WARNING]
>
> Firewall blocked 1 domain
>
> The following domain was blocked by the firewall during workflow execution:
>
> - `southcentralus0.in.applicationinsights.azure.com`
>
> To allow these domains, add them to the `network.allowed` list in your workflow frontmatter:
>
> ```yaml
> network:
> allowed:
> - defaults
> - "southcentralus0.in.applicationinsights.azure.com"
> ```
>
> See [Network Configuration](https://github.github.com/gh-aw/reference/network/) for more information.
>
>

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34696563755/agentic_workflow) workflow. · auto · 186.4 AIC · ⌖ 13.3 AIC · ⊞ 15.9K · [◷]( · [◷](https://github.com/search?q=repo:microsoft%2Ftestfx+is:issue+%22gh-aw-workflow-call-id:+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

## Performance Opportunities Backlog

- PrivateObject.Helpers.cs generic-method cache (net-fx only) - low priority
- TestExecutionManager.ParallelExecution.cs per-test array wrapping - inherent design, low priority
- AggregatedConfiguration indexer scan - low impact (re-verified 2026-09-13: downstream consumers cache via static MSTestSettings.CurrentSettings singleton, confirmed no per-test hot-path bug)
- ServerTestHost.RequestExecution.cs Select+ToArray - per-request not per-test, low impact
- RetryArtifactProcessor.cs GroupBy/Count double-enumeration - low volume, low priority
- RetryOrchestrator.ArtifactRecovery.cs Any() per-manifest-line - low volume, low priority

## Discovered Commands

- Build (Debug): `./build.sh`
- Build (Release): `./build.sh -c Release`
- Pack (NuGet packages, required for acceptance/integration tests): `./build.sh -pack`
- Unit tests: `./build.sh -test`
- Integration + acceptance tests: `./build.sh -pack -test -integrationTest`
- Benchmarks: `dotnet run --project test/Performance/MSTest.Performance.Benchmarks -c Release --no-build -- --filter "**" --job short`
- Note: net462/net48-targeting unit test projects (e.g. `MSTestAdapter.PlatformServices.UnitTests`, `MSTestAdapter.UnitTests`) cannot be built/run standalone on this Linux sandbox (no .NET Framework SDK); TargetFrameworks cannot be restricted via `-p:` CLI override for these multi-targeted projects.

## Run History

### 2026-09-03 - [Run](https://github.com/microsoft/testfx/actions/runs/34127948931)
- 🔍 Scanned MSTest.TestAdapter/Discovery remainder, Platform Logging internals, CrashDump/HangDump internals, TrxReport/AzureDevOpsReport internals, TestFramework.Extensions DataRow/DynamicData resolver chain, Analyzers fixers - no new hot-path findings> [!WARNING]
>
> Firewall blocked 1 domain
>
> The following domain was blocked by the firewall during workflow execution:
>
> - `southcentralus0.in.applicationinsights.azure.com`
>
> To allow these domains, add them to the `network.allowed` list in your workflow frontmatter:
>
> ```yaml
> network:
> allowed:
> - defaults
> - "southcentralus0.in.applicationinsights.azure.com"
> ```
>
> See [Network Configuration](https://github.github.com/gh-aw/reference/network/) for more information.
>
>

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34759985386/agentic_workflow) workflow. · auto · 184.6 AIC · ⌖ 18.9 AIC · ⊞ 15.9K · [◷]( · [◷](https://github.com/search?q=repo:microsoft%2Ftestfx+is:issue+%22gh-aw-workflow-call-id:+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

## Performance Opportunities Backlog

- PrivateObject.Helpers.cs generic-method cache (net-fx only) - low priority
- TestExecutionManager.ParallelExecution.cs per-test array wrapping - inherent design, low priority
- AggregatedConfiguration indexer scan - low impact, re-verified accurate
- ServerTestHost.RequestExecution.cs Select+ToArray - per-request not per-test, low priority
- RetryArtifactProcessor.cs GroupBy/Count double-enumeration - low volume, low priority
- RetryOrchestrator.ArtifactRecovery.cs Any() per-manifest-line - low volume, low priority

*(Backlog is very slim after ~7 weeks of near-daily scans; codebase is thoroughly optimized on hot paths.)*

## Discovered Commands

## Run History

### 2026-09-09 - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- 🔍 Scanned HotReload, Telemetry, TrxReport, AzureDevOpsReport, VSTestBridge remaining files - no new findings

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34849959068/agentic_workflow) workflow. · copilot · auto · 98.1 AIC · ⌖ 8.05 AIC · ⊞ 16.5K · [◷]( · [◷](https://github.com/search?q=repo:microsoft%2Ftestfx+is:issue+%22gh-aw-workflow-call-id:+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

## Performance Opportunities Backlog

- PrivateObject.Helpers.cs generic-method cache (net-fx only) - low priority
- TestExecutionManager.ParallelExecution.cs per-test array wrapping - inherent design, low priority
- AggregatedConfiguration indexer scan - low impact, re-verified accurate
- ServerTestHost.RequestExecution.cs Select+ToArray - per-request not per-test, low priority
- RetryArtifactProcessor.cs GroupBy/Count double-enumeration - low volume, low priority
- RetryOrchestrator.ArtifactRecovery.cs Any() per-manifest-line - low volume, low priority

*(Backlog remains very slim after ~8 weeks of near-daily scans; codebase is thoroughly optimized on hot paths.)*

## Discovered Commands

## Run History

### 2026-09-09 - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- 🔍 Scanned HotReload, Telemetry, TrxReport, AzureDevOpsReport, VSTestBridge remaining files - no new findings

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/34975663036/agentic_workflow) workflow. · copilot · auto · 108.2 AIC · ⌖ 7.04 AIC · ⊞ 16.5K · [◷]( · [◷](https://github.com/search?q=repo:microsoft%2Ftestfx+is:issue+%22gh-aw-workflow-call-id:+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

> [!WARNING]
>
> Firewall blocked 1 domain
>
> The following domain was blocked by the firewall during workflow execution:
>
> - `southcentralus0.in.applicationinsights.azure.com`
>
> To allow these domains, add them to the `network.allowed` list in your workflow frontmatter:
>
> ```yaml
> network:
> allowed:
> - defaults
> - "southcentralus0.in.applicationinsights.azure.com"
> ```
>
> See [Network Configuration](https://github.github.com/gh-aw/reference/network/) for more information.
>
>

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/35102604382/agentic_workflow) workflow. · copilot · auto · 178.8 AIC · ⌖ 15.5 AIC · ⊞ 16.5K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

* [ ] **Review PR**: "[perf-improver] Add benchmark coverage for CollectionAssert.AreEquivalent" (branch `perf-assist/collectionassert-equivalence-benchmark`) - [Repo PRs](https://github.com/microsoft/testfx/pulls)
* [ ] **Review PR**: "[perf-improver] Add benchmark coverage for ObjectModelConverters.FixUpTestCase" (branch `perf-assist/objectmodelconverters-fixuptestcase-benchmark`) - [Repo PRs](https://github.com/microsoft/testfx/pulls)

## Performance Opportunities Backlog

- PrivateObject.Helpers.cs generic-method cache (net-fx only) - low priority
- TestExecutionManager.ParallelExecution.cs per-test array wrapping - inherent design, low priority
- AggregatedConfiguration indexer scan - low impact, re-verified accurate
- ServerTestHost.RequestExecution.cs Select+ToArray - per-request not per-test, low priority
- RetryArtifactProcessor.cs GroupBy/Count double-enumeration - low volume, low priority
- RetryOrchestrator.ArtifactRecovery.cs Any() per-manifest-line - low volume, low priority

*(Backlog remains very slim after ~8 weeks of near-daily scans; codebase is thoroughly optimized on hot paths. Measurement infrastructure work (Task 6) has been the recent focus given diminishing returns from blind scanning.)*

## Discovered Commands

```sh
./build.sh # restore + build (Debug)
./build.sh -test # build + unit tests
./build.sh -pack # produce NuGet packages
./build.sh -pack -test -integrationTest # full suite (slow)
```
SDK: 11.0.100-preview.7.26376.106 (bootstrapped via `./build.sh` into `.dotnet/`). Note: MSTestAdapter.UnitTests and other net48-targeting tests can't run in this Linux sandbox (no .NET Framework SDK); TargetFrameworks cannot be restricted via `-p:` CLI override for these multi-targeted projects. VSTest/MSTest-legacy-based test projects (e.g. `Microsoft.Testing.Extensions.VSTestBridge.UnitTests`) use `--filter "FullyQualifiedName~ClassName"`, not `--treenode-filter` (that's MTP-only).

## Run History

### 2026-09-17 - [Run](https://github.com/microsoft/testfx/actions/runs/35227706065)
- 🔧 Created PR: Add benchmark coverage for ObjectModelConverters.FixUpTestCase (branch `perf-assist/objectmodelconverters-fixuptestcase-benchmark`)
- 📊 Measured: FixUpTestCase 3.345us/112B alloc per call (new baseline benchmark, no production code change)

### 2026-09-16 - [Run](https://github.com/microsoft/testfx/actions/runs/35102604382)
- 🔧 Created PR: Add benchmark coverage for CollectionAssert.AreEquivalent (branch `perf-assist/collectionassert-equivalence-benchmark`)
- 📊 Measured: small (5-item) 693.6ns/1.32KB, large (1000-item) 108.6μs/246.7KB - confirms dictionary-counting cost scales with collection size

### 2026-09-15 - [Run](https://github.com/microsoft/testfx/actions/runs/34975663036)
- 🔍 Scanned Platform/Services, Platform/Messages+Requests, Platform/OutputDevice+Terminal, TestFramework CollectionAssert/StringAssert - no new hot-path findings, everything already optimized (dict-based, no LINQ in per-test paths)
- 💬 No open performance-labeled issues, no open perf-improver PRs, no new commits since last run
- 📊 Runtime hot-path scans found nothing new for ~3 weeks across nearly every subsystem - shifted weight toward Task 6 (measurement infrastructure)

### 2026-09-14 - [Run](https://github.com/microsoft/testfx/actions/runs/34849959068)
- 🔄 Confirmed PRs #11225 (analyzer check reorder) and #11242 (TelemetryCollector benchmarks) merged by maintainer
- 🔍 Scanned Configurations, MSTestAdapter.PlatformServices Utilities, remaining Assert*.cs files, recent commits - no new findings

### 2026-09-13 - [Run](https://github.com/microsoft/testfx/actions/runs/34759985386)
- 🔧 Created PR: Add benchmark coverage for TelemetryCollector.TrackAssertionCall
- 🔍 Re-verified AggregatedConfiguration/MSTestSettings caching claim - accurate, no bug

### 2026-09-12 - [Run](https://github.com/microsoft/testfx/actions/runs/34696563755)
- 🔧 Created PR: Reorder cheap checks before GetFrameworkAssembly in InheritedMemberFromDifferentMSTestVersionAnalyzer (~18% faster on synthetic benchmark)

### 2026-09-11 - [Run](https://github.com/microsoft/testfx/actions/runs/34604797665)
- 🔍 Scanned MSTest.Analyzers.CodeFixes, HtmlReport, MSTestAdapter.PlatformServices/Services remaining files, Platform/Extensions remaining files - no new hot-path findings

### 2026-09-10 - [Run](https://github.com/microsoft/testfx/actions/runs/34483050997)
- 🔍 Scanned MSTest.Analyzers and Discovery remaining files - no hot-path issues; flagged analyzer LINQ chain as low-confidence candidate (later fixed 09-12)

### 2026-09-09 - [Run](https://github.com/microsoft/testfx/actions/runs/34357735119)
- 🔍 Scanned HotReload, Telemetry, TrxReport, AzureDevOpsReport, VSTestBridge remaining files - no new findings

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/35227706065/agentic_workflow) workflow. · copilot · auto · 261.3 AIC · ⌖ 11.8 AIC · ⊞ 16.5K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/perf-improver.md@main
```

---

## Activity for September 2026

## Suggested Actions for Maintainer

* [ ] **Review PR** #aw_omcbench: [perf-improver] Add benchmark coverage for ObjectModelConverters.FixUpTestCase - benchmark-only addition (VSTestBridge FixUpTestCase, ~4.6us/112B alloc baseline), no runtime behavior change

## Performance Opportunities Backlog

## Discovered Commands

## Run History

### 2026-09-18 13:33 UTC - [Run](https://github.com/microsoft/testfx/actions/runs/35350698344)
- 🔍 Scanned Configurations/Platform Hosts/Assert fast-path assertions - no new hot-path findings
- 🔧 Created PR: Add benchmark coverage for ObjectModelConverters.FixUpTestCase (branch `perf-assist/objectmodelconverters-fixuptestcase-benchmark`)
- 📊 Measured: FixUpTestCase 4.626us/112B alloc per call (new baseline)

### 2026-09-17 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 🔧 Created PR: Add benchmark coverage for ObjectModelConverters.FixUpTestCase (branch `perf-assist/objectmodelconverters-fixuptestcase-benchmark`)
- 📊 Measured: FixUpTestCase 3.345us/112B alloc per call

### 2026-09-16 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 🔧 Created PR: Add benchmark coverage for CollectionAssert.AreEquivalent (merged as #11331)
- 📊 Measured: small (5-item) 693.6ns/1.32KB, large (1000-item) 108.6us/246.7KB

### 2026-09-15 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 🔍 Scanned Platform/Services, Messages/Requests, Terminal reporting, CollectionAssert/StringAssert - no new hot-path findings

### 2026-09-14 - [Run](https://github.com/microsoft/testfx/actions/runs/34232585148)
- 🔍 Confirmed PR #11225 (analyzer reorder) and #11242 (TelemetryCollector benchmarks) both merged
- 🔍 Scanned Configurations, PlatformServices remaining files, Assert*.cs remainder - no new findings

> [!WARNING]
>
> Firewall blocked 2 domains
>
> The following domains were blocked by the firewall during workflow execution:
>
> - `github.com`
> - `southcentralus0.in.applicationinsights.azure.com`
>
> To allow these domains, add them to the `network.allowed` list in your workflow frontmatter:
>
> ```yaml
> network:
> allowed:
> - defaults
> - "github.com"
> - "southcentralus0.in.applicationinsights.azure.com"
> ```
>
> See [Network Configuration](https://github.github.com/gh-aw/reference/network/) for more information.
>
>

> 🤖 **Automated content by GitHub Copilot.** Generated by the [Perf Improver](https://github.com/microsoft/testfx/actions/runs/35350698344/agentic_workflow) workflow. · copilot · auto · 276.2 AIC · ⌖ 9.86 AIC · ⊞ 16K · [◷]( · [◷](https://github.com/search?q=repo%3Amicrosoft%2Ftestfx+is%3Aissue+%22gh-aw-workflow-call-id%3A+microsoft%2Ftestfx%2Fperf-improver%22&type=issues))
> _{Comment /perf-assist to run again}
>

_{Add this agentic workflow to your repo}

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```

Contributor guide

Open the contributing guide

Research direction

This issue is a monthly performance report, not a defined code change; review the listed backlog entries, including PrivateObject.Helpers.cs and TestExecutionManager.ParallelExecution.cs, to understand the remaining opportunities. Start with ./build.sh -test if validating the repository, but the report does not define a specific change or clear completion criteria.

Written by the indexing model from the issue text.

Assessment

Tech stack: csharp
Domain: performance, testing
Issue type: Documentation
Difficulty: 5/5
Estimated time: Over a week
Activity status: Active
Clarity: Needs clarification
Newbie friendliness: 25/100

[perf-improver] Monthly Activity 2026-09

Description

Contributor guide

Research direction

Assessment

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