Add CoreCLR WASM R2R performance lane

[lewing]

Summary

• add a dedicated CoreCLR browser-WASM R2R microbenchmark lane on V8
• propagate the R2R selection through Helix and the microbenchmark harness
• publish per-assembly WASM R2R with a distinct R2RType=r2r result dimension
• resolve the CoreCLR browser runtime pack in shared WASM pack overrides
• fail fast if CoreCLR/R2R/webcil/runtime-pack settings are not applied

Dependency

Depends on dotnet/runtime#133040, which stages the matching host Crossgen2 pack in BrowserWasmCoreCLR.

Validation

• focused Python tests for argument validation, environment propagation, Helix forwarding, and result dimensions
• direct MSBuild evaluation of R2R and runtime-pack properties
• fail-fast MSBuild validation for invalid Mono/R2R configuration
• XML and YAML parsing

Remaining validation

Run runtime-wasm-perf with this branch and the runtime artifact together, confirm CreateReadyToRunImages executes, and verify uploaded results are labeled R2RType=r2r.

[Copilot]

🔵 Needs a closer look

It changes CI/Helix orchestration and MSBuild/runtime-pack resolution behavior where correctness is environment-dependent and should be validated by a human with end-to-end runs.

Pull request overview

Adds a dedicated CoreCLR browser-WASM ReadyToRun (R2R) microbenchmark lane (V8) and wires the R2R selection through the performance repo’s Helix/job plumbing and MSBuild configuration, including validation to fail fast when required settings aren’t applied.

Changes:

• Adds CoreCLR-vs-Mono runtime-pack override logic for WASM builds and validates the expected CoreCLR runtime pack for R2R runs.
• Introduces --wasm-ready-to-run end-to-end (CLI arg → env var → MSBuild properties → Helix forwarding) and emits a distinct R2RType=r2r run dimension.
• Adds a non-release-branch pipeline lane for CoreCLR WASM R2R microbenchmarks on V8 plus focused pytest coverage.

File summaries

File	Description
src/scenarios/build-common/WasmOverridePacks.targets	Chooses CoreCLR vs Mono WASM runtime-pack IDs based on UseMonoRuntime.
src/benchmarks/micro/MicroBenchmarks.Wasm.targets	Enables/validates CoreCLR WASM R2R publish properties and validates runtime-pack selection.
scripts/tests/test_wasm_coreclr_r2r.py	Adds pytest coverage for argument validation, env propagation, Helix forwarding, and result dimensions.
scripts/run_performance_job.py	Forwards --wasm-ready-to-run to Helix work items and adds R2RType=r2r dimension.
scripts/micro_benchmarks.py	Adds --wasm-ready-to-run and propagates it via PERFLAB_WASM_READY_TO_RUN.
eng/pipelines/runtime-wasm-perf-jobs.yml	Adds a CoreCLR WASM R2R microbenchmark lane (non-release branches), V8 on linux_x64.

Review details

• Files reviewed: 6/6 changed files
• Comments generated: 0
• Review effort level: Lite

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[lewing]

dotnet/runtime#133040 is the runtime side

[Copilot]

🔵 Needs a closer look

End-to-end validation remains pending and the required runtime dependency is not yet merged.

Review details

• Files reviewed: 6/6 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[lewing]

test run at https://dev.azure.com/dnceng-public/public/_build/results?buildId=1579394

[lewing]

Pushed c10ff6c to fix the first end-to-end validation failure from runtime-wasm-perf build 1579394. The runtime artifact correctly contained the local WebAssembly SDK and Crossgen2 packages at 11.0.0-ci, but generated benchmark restore requested the runtime product version (11.0.0-rc.1.26431.109). The payload now detects the shared local toolchain package version, exports it to Helix, and applies it to both KnownWebAssemblySdkPack and KnownCrossgen2Pack. Focused tests cover detection, mismatch rejection, propagation, and MSBuild properties. A new pipeline run is required.

[Copilot]

🔵 Needs a closer look

The environment-dependent MSBuild and Helix integration still requires the stated end-to-end validation after the latest package-version fix.

Review details

• Files reviewed: 7/7 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[lewing]

https://dev.azure.com/dnceng-public/public/_build/results?buildId=1579662

[lewing]

is there a better (non-workload) way to use the crossgen from the build?

[lewing]

Build 1579662 was green but did not actually compile the benchmark app as R2R: the inner-TFM restore evaluation reset KnownWebAssemblySdkPack to the product version, restored feed package .118, and therefore never imported the new CoreCLR R2R targets. The publish binlog showed CreateReadyToRunImages completing in 1 ms with no _ReadyToRunFilesToPublish. Pushed a fix that reapplies both local toolchain versions immediately before ProcessFrameworkReferences, following the runtime WASM test pattern, and now fails the build if _CreateR2RImages produces no outputs. Another validation run is required.

[Copilot]

🔵 Needs a closer look

The configuration validation runs after publishing rather than failing before build work begins.

Review details

Suppressed comments (1)

Previously missed (1) — in code that hasn't changed since the last review.

src/benchmarks/micro/MicroBenchmarks.Wasm.targets:21

• PrepareForWasmBuild is a BenchmarkDotNet-generated target that runs AfterTargets="Publish", so this validation occurs only after the full publish/R2R work has already completed. Invalid Mono/R2R or package settings therefore do not fail fast as described; hook this validation before framework-pack resolution (or another pre-build target) instead.

• Files reviewed: 7/7 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[lewing]

https://dev.azure.com/dnceng-public/public/_build/results?buildId=1579905&view=results

[lewing]

the crossgen we're building for the pipeline had a newer glibc because it wasn't crossbuilt dotnet/runtime#133143 it the fix for that and I will rereun the test once it is in.

[Copilot]

🔵 Needs a closer look

Payload construction requires an ILLink package that the referenced runtime artifact does not stage.

Review details

Suppressed comments (1)

scripts/build_runtime_payload.py:410

• The BrowserWasmCoreCLR artifact producer stages the WebAssembly SDK, ref pack, and (via runtime#133040) Crossgen2 package, but it does not stage any Microsoft.NET.ILLink.Tasks nupkg under staging/built-nugets. Consequently every CoreCLR WASM job now reaches this check with zero ILLink packages and fails while constructing the payload, before the new R2R work item can run. Either stage the matching ILLink package in the runtime artifact or stop requiring a package that is not part of that artifact contract.

    illink_packages = [
        package for package in Path(built_nugets_dir).glob("Microsoft.NET.ILLink.Tasks.*.nupkg")
        if not package.name.endswith(".symbols.nupkg")
    ]
    if len(illink_packages) != 1:

• Files reviewed: 7/7 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[lewing]

Local coherent-VMR validation completed against BAR 330383 / AzDO 3065542 with no local version override. After excluding Jil.dll from R2R and cleaning generated outputs, restore, ILLink, Crossgen, WebCIL publish, and V8 execution all succeeded: 119 non-empty R2R images, 157 valid WebCIL files, and all 14 Perf_Boolean cases executed. Jil remains as validated IL-only WebCIL because Crossgen currently emits invalid WASM for its ISO8601 TimeSpan deserializer. Pushed the narrow exclusion.

[Copilot]

🔵 Needs a closer look

The runtime artifact omits the newly required ILLink package, causing CoreCLR WASM jobs to fail before Helix.

Review details

Suppressed comments (1)

scripts/build_runtime_payload.py:410

• The BrowserWasmCoreCLR artifact produced by the declared runtime dependency does not contain an ILLink package: runtime#133040 stages only the WebAssembly SDK pack, ref pack, and Crossgen2 under staging/built-nugets. Consequently this list is empty and payload construction now aborts before Helix for every wasm_coreclr job, including the existing non-R2R lane. Please also stage the matching non-symbol Microsoft.NET.ILLink.Tasks package in the producer, or stop requiring and overriding it here.

    illink_packages = [
        package for package in Path(built_nugets_dir).glob("Microsoft.NET.ILLink.Tasks.*.nupkg")
        if not package.name.endswith(".symbols.nupkg")
    ]
    if len(illink_packages) != 1:

• Files reviewed: 7/7 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[lewing]

successful run https://dev.azure.com/dnceng-public/public/_build/results?buildId=1584001&view=results

[Copilot]

🟡 Changes recommended

Payload validation rejects the actual runtime artifact and regresses non-R2R CoreCLR WASM runs.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

Suppressed comments (1)

scripts/build_runtime_payload.py:412

• The linked BrowserWasmCoreCLR producer stages only the WebAssembly SDK/ref packages and the newly added Crossgen2 package in staging/built-nugets; it does not stage a Microsoft.NET.ILLink.Tasks nupkg. This check therefore raises “found 0” for every CoreCLR WASM job before Helix submission, including the existing non-R2R lane. Either stage the matching ILLink package in the runtime artifact or validate/use the ILLink pack already installed in dotnet-none instead.

    illink_packages = [
        package for package in Path(built_nugets_dir).glob("Microsoft.NET.ILLink.Tasks.*.nupkg")
        if not package.name.endswith(".symbols.nupkg")
    ]
    if len(illink_packages) != 1:
        raise ValueError(
            f"Expected one ILLink package in {built_nugets_dir}, found {len(illink_packages)}")

• Files reviewed: 7/7 changed files
• Comments generated: 2
• Review effort level: Balanced

[Copilot]

🔵 Needs a closer look

Approval depends on coordinated runtime artifacts and final end-to-end validation of the cross-repository toolchain path.

Review details

• Files reviewed: 7/7 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[Copilot]

🟡 Changes recommended

The new package-version requirement breaks an existing wasm_coreclr unit-test path.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

• Files reviewed: 7/7 changed files
• Comments generated: 1
• Review effort level: Balanced

[Copilot]

🔵 Needs a closer look

The cross-repository runtime artifact dependency and end-to-end R2R publishing behavior require final human validation.

Review details

• Files reviewed: 8/8 changed files
• Comments generated: 0 new
• Review effort level: Balanced