[mono][sgen] Add option to disable tarjan gc bridge optimization #121243
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This option is also currently causing crashes in the gc bridge.
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Tagging subscribers to this area: @BrzVlad |
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Pull Request Overview
This pull request fixes an indexing bug in the Tarjan bridge color table dump function and adds a new GC parameter option for disabling non-bridge strongly connected components (SCCs).
- Fixed incorrect loop counter increment in
dump_color_tablefunction - Added support for
disable-non-bridge-sccGC parameter option
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| src/mono/mono/metadata/sgen-tarjan-bridge.c | Moved counter increment from outer loop to inner loop to correctly count color data entries instead of buckets |
| src/mono/mono/metadata/sgen-bridge.c | Added parameter handling for the disable-non-bridge-scc configuration option |
filipnavara
approved these changes
Oct 31, 2025
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/ba-g android infra issue |
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/backport to release/9.0-staging |
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Started backporting to |
Merged
4 tasks
BrzVlad
added a commit
that referenced
this pull request
Nov 6, 2025
…idge optimization (#121376) Backport of #121243 to release/9.0-staging /cc @BrzVlad ## Customer Impact - [x] Customer reported - [ ] Found internally Applications on maui-android can randomly crash during GC. We've had a few fixes for the tarjan bridge merged a few months ago, but there is still one more issue. The problem is caused by a specific optimization inside the tarjan gc bridge. The only workaround for a customer hitting this failure is to configure an environment variable so that their app uses a different gc bridge (which has worse performance). One customer reported that using the older gc bridge makes the application unusable due to degradation of performance. This PR allows users to opt out of a smaller optimization and keep using the tarjan gc bridge, as a workaround for .NET9. ## Regression - [ ] Yes - [x] No ## Testing Tested on our own gc bridge tests, with scenario causing the issue. ## Risk This PR has zero risk since it just adds support for disabling an optimization. By default, there is no change in behavior. I plan to backport to .NET10 the actual fix for this issue. --------- Co-authored-by: Vlad Brezae <brezaevlad@gmail.com>
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This option is also currently causing crashes in the gc bridge.