Fix NativeAOT string GC config handling by janvorli · Pull Request #128455 · dotnet/runtime

janvorli · 2026-05-21T15:28:06Z

The NativeAOT doesn't have real implementation of
GCToEEInterface::GetStringConfigValue, the method
just return false. That prevents extraction of
settings that are strings, like GCHeapAffinitizeRanges.

This change fixes it by adding proper implementation.

Close#128396

The NativeAOT doesn't have real implementation of GCToEEInterface::GetStringConfigValue, the method just return false. That prevents extraction of settings that are strings, like GCHeapAffinitizeRanges. This change fixes it by adding proper implementation. Closedotnet#128396

dotnet-policy-service · 2026-05-21T15:29:24Z

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Pull request overview

This PR updates the NativeAOT runtime’s GC configuration plumbing so that string-valued GC configs can be retrieved (instead of always being treated as absent), bringing NativeAOT behavior closer to CoreCLR for settings like heap affinitization ranges.

Changes:

Add NativeAOT RhConfig helpers to read string config values from DOTNET_* environment variables and from embedded config blobs.
Implement GCToEEInterface::GetStringConfigValue for NativeAOT by delegating to the new RhConfig string readers.
Route GCToEEInterface::FreeStringConfigValue through RhConfig for consistent ownership handling.

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Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
src/coreclr/nativeaot/Runtime/RhConfig.h	Adds declarations for reading and freeing string config values (settings + knobs).
src/coreclr/nativeaot/Runtime/RhConfig.cpp	Implements string config retrieval (env + embedded) and centralized freeing.
src/coreclr/nativeaot/Runtime/gcenv.ee.cpp	Wires GC string config lookup/freeing to `RhConfig` for NativeAOT.

Co-authored-by: Jan Kotas <jkotas@microsoft.com>

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MichalStrehovsky · 2026-05-25T01:26:19Z

I am not sure how to test it in a regression test. The affinitization applies to GC threads, not regular threads, so it is not visible to the user code.

Could we update the GetConfigurationVariables.cs test to test this? The test is not really testing anything right now: mark the test as RequiresProcessIsolation, add CLRTestEnvironmentVariable setting this, and verify we can see it in GetConfigurationVariables.

MichalStrehovsky

Looks like the test needs TestLibrary.PlatformDetection.IsMonoRuntime conditioning, but LGTM otherwise, thanks!

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VSadov

LGTM

janvorli · 2026-06-02T12:55:32Z

/backport to release/10.0

github-actions · 2026-06-02T12:55:45Z

Started backporting to release/10.0 (link to workflow run)

@janvorli

Backport of #128455 to release/10.0 /cc @janvorli ## Customer Impact - [x] Customer reported - issue #128396 - [ ] Found internally When publishing with NativeAOT (PublishAot=true), the GCHeapAffinitizeRanges configuration is ignored regardless of how it is supplied — RuntimeHostConfigurationOption in the .csproj, IlcArg --runtimeopt:, or the DOTNET_GCHeapAffinitizeRanges environment variable. The Server GC heap threads fall back to the default per-heap affinity (heap 0 → CPU 0, heap 1 → CPU 1, etc.) instead of the user-specified ranges. The same configuration works correctly in non-AOT builds. ## Regression - [ ] Yes - [x] No ## Testing Local testing using targeted repro app provided by the customer, local NativeAOT tests execution, CI. ## Risk Low, the change is specific to string config values handling in NativeAOT that was ignoring those before. --------- Co-authored-by: Jan Vorlicek <janvorli@microsoft.com> Co-authored-by: Jan Kotas <jkotas@microsoft.com> Co-authored-by: Michal Strehovský <MichalStrehovsky@users.noreply.github.com>

janvorli added this to the 11.0.0 milestone May 21, 2026

janvorli self-assigned this May 21, 2026

CopilotAI review requested due to automatic review settings May 21, 2026 15:28

janvorli requested a review from MichalStrehovsky as a code owner May 21, 2026 15:28

janvorli added the area-NativeAOT-coreclr label May 21, 2026

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Comment threadsrc/coreclr/nativeaot/Runtime/gcenv.ee.cpp Outdated

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Comment threadsrc/coreclr/nativeaot/Runtime/RhConfig.cpp
Comment threadsrc/coreclr/nativeaot/Runtime/gcenv.ee.cpp Outdated
Comment threadsrc/coreclr/nativeaot/Runtime/gcenv.ee.cpp

Apply suggestion from@jkotas
f593671
Co-authored-by: Jan Kotas <jkotas@microsoft.com>

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Reflect feedback
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Comment threadsrc/coreclr/nativeaot/Runtime/RhConfig.cpp
Comment threadsrc/coreclr/nativeaot/Runtime/gcenv.ee.cpp Outdated
Comment threadsrc/coreclr/nativeaot/Runtime/gcenv.ee.cpp

AustinWise reviewed May 21, 2026
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Comment threadsrc/coreclr/nativeaot/Runtime/gcenv.ee.cpp Outdated

Make it resilient to allocation errors
9187afe

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This was referenced May 21, 2026
slow macOS - "##[error]The job running on agent Azure Pipelines 9 ran longer than the maximum time of 60 minutes." dotnet/dnceng#1883
Open
The Operation will be canceled. The next steps may not contain expected logs. dotnet/dnceng#3008
Open

Modify GetConfigurationVariables test to verify this change
d5260ea

build-analysisBot mentioned this pull request May 25, 2026
XHarness package install failure on iOS due to devicectl NSPOSIXErrorDomain error 49 #123796
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MichalStrehovsky approved these changes May 26, 2026
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Do not check for the GCHeapAffinitizeRanges presence on Mono
7d348dd

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MichalStrehovsky added 2 commits May 27, 2026 10:38

Add ProjectReference and update CLRTestEnvironmentVariable
a226606

Add CLRTestEnvironmentVariable for GCHeapAffinitizeRanges
0b907e3

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VSadov approved these changes May 27, 2026
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janvorli merged commit 6684fb2 into dotnet:mainMay 29, 2026
107 of 117 checks passed

dotnet-maestroBot mentioned this pull request May 30, 2026
[main] Source code updates from dotnet/runtime dotnet/dotnet#6925
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dotnet-milestone-botBot modified the milestones: 11.0.0, 11.0-preview6 May 30, 2026

github-actionsBot mentioned this pull request Jun 2, 2026
[release/10.0] Fix NativeAOT string GC config handling #128894
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