perf(blockchain): make ChainHeadSpecProvider lock-free#11618
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LukaszRozmej merged 2 commits intoMay 18, 2026
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Replace lock + paired field updates with an immutable (Number, Spec) record published via Volatile.Read/Volatile.Write. GetSpec is deterministic per (number, header) so last-writer-wins is safe. Closes NethermindEth#11367.
- Drop redundant single-call test (subsumed by the repeat-call cache test) - Add null-header fallback test for the ForkActivation path - Rework the head-rotation race test: cancellation-driven loop with stricter set-membership assertion so a torn pair surfaces as a non-matching reference - Note in ChainHeadSpecProvider why CachedSpec must remain a record (class) rather than a record struct (16-byte writes are not atomic) Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
LukaszRozmej
approved these changes
May 15, 2026
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@damian-orzechowski @wurdum is this fine for Arbitrum? I remember we had some issues around that |
svlachakis
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May 18, 2026
damian-orzechowski
approved these changes
May 18, 2026
svlachakis
approved these changes
May 18, 2026
hudem1
approved these changes
May 18, 2026
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Resolves #11367
Changes
ChainHeadSpecProvider.GetCurrentHeadSpecis now lock-free. The cached(headerNumber, releaseSpec)pair is wrapped in an immutableCachedSpecrecord and published through a single reference field withVolatile.Read/Volatile.Write.Lock _lock, the paired_lastHeader/_headerSpecfields, and the read-then-double-checked-write block.(number, spec)pair, and concurrent writers race to publish equivalent values for the same headerNumber (GetSpec(header)is deterministic).Types of changes
What types of changes does your code introduce?
Testing
Requires testing
If yes, did you write tests?
Notes on testing
ChainHeadSpecProviderTests(5 cases): basic resolution, single-resolve on repeated same-head call, re-resolve on head change, 32 readers x 5000 iterations against a stable head, and a head-rotation race with 16 workers asserting every observed spec belongs to the published mapping. No production hot-path callers needed updating.Documentation
Requires documentation update
Requires explanation in Release Notes