feat(arbos60): add multi-gas constraints pricing model by AnkushinDaniil · Pull Request #700 · NethermindEth/nethermind-arbitrum

AnkushinDaniil · 2026-03-02T17:25:53Z

Summary

Implements ArbOS 60 multi-gas constraints pricing model with per-resource weights. Includes MultiGas tracking fixes and comparison mode test isolation improvements (merged from #723).

Key Features

Core Pricing Model

GasModel enum for routing: Legacy, SingleGasConstraints, MultiGasConstraints
Weighted backlog calculation with saturating arithmetic
Per-resource exponent calculation with MaxPricingExponentBips cap (85,000)
Input validation and bounds checking throughout
Production wiring: UpdateGasPool now calls GrowBacklog(computeGas, AccumulatedMultiGas) for ArbOS 60+

MultiGas Tracking (from #723)

Register receipt decoder so MultiGas fields persist correctly in storage
Track precompile output data as Computation gas
Track code deposit gas as StorageGrowth
Owner precompiles don't charge multigas (return zero gas)

Comparison Mode (from #723)

Reset BlockTree internal state (Head, BestKnownNumber) between tests via IResettableBlockTree
Add Genesis null checks to handle reinitialized state gracefully
Enable debug logging for troubleshooting

Architecture

Gas Model Selection

flowchart TD
    Start([GetGasModelToUse]) --> V60{ArbOS >= 60?}
    V60 -->|Yes| MC{MultiGasConstraints<br/>Length > 0?}
    MC -->|Yes| MGC[MultiGasConstraints]
    MC -->|No| V50
    V60 -->|No| V50{ArbOS >= 50?}
    V50 -->|Yes| SC{Constraints<br/>Length > 0?}
    SC -->|Yes| SGC[SingleGasConstraints]
    SC -->|No| LEG[Legacy]
    V50 -->|No| LEG

    style MGC fill:#22c55e,stroke:#16a34a,color:#000
    style SGC fill:#3b82f6,stroke:#2563eb,color:#000
    style LEG fill:#a1a1aa,stroke:#71717a,color:#000

Storage Layout

classDiagram
    class MultiGasConstraint {
        <<12 slots>>
        +ulong Target
        +uint AdjustmentWindow
        +ulong Backlog
        +ulong MaxWeight
        +ulong WeightedResources_8
        +GrowBacklog(MultiGas)
        +ShrinkBacklog(MultiGas)
    }

    class MultiGasFees {
        <<16 slots>>
        +UInt256 NextBlockFees_8
        +UInt256 CurrentBlockFees_8
        +CommitNextToCurrent()
    }

    class GasConstraint {
        <<3 slots - Legacy>>
        +ulong Target
        +ulong AdjustmentWindow
        +ulong Backlog
    }

    class ResourceKind {
        <<enum>>
        Unknown
        Computation
        HistoryGrowth
        StorageAccess
        StorageGrowth
        L1Calldata
        L2Calldata
        WasmComputation
    }

    MultiGasConstraint --> ResourceKind : weights per kind
    MultiGasFees --> ResourceKind : fees per kind

Pricing Update Flow (Per Block)

sequenceDiagram
    participant Block as Block Producer
    participant L2P as L2PricingState
    participant MGC as MultiGasConstraint
    participant MGF as MultiGasFees
    participant Storage as BaseFeeWei

    Block->>L2P: UpdatePricingModel(timePassed)
    
    Note over L2P: Model = MultiGasConstraints
    
    loop For each constraint
        L2P->>MGC: Get backlog, target
        L2P->>L2P: newBacklog = backlog - timePassed * target
        L2P->>MGC: SetBacklog(newBacklog)
    end
    
    L2P->>L2P: CalcMultiGasConstraintsExponents()
    Note over L2P: exponent = backlog * weight * BIPS / divisor
    
    loop For each ResourceKind
        L2P->>L2P: baseFee = minBaseFee * exp(exponent)
        L2P->>MGF: SetNextBlockFee(kind, baseFee)
    end
    
    L2P->>Storage: Set max of all baseFees
    
    Block->>L2P: CommitMultiGasFees()
    L2P->>MGF: CommitNextToCurrent()
    Note over MGF: nextBlockFees copied to currentBlockFees

Transaction Gas Tracking

flowchart LR
    subgraph TX [Transaction Execution]
        OP[EVM Opcode] -->|gas + resourceKind| ACC[Accumulate MultiGas]
    end

    subgraph GROW [Post-TX: UpdateGasPool → GrowBacklog]
        ACC -->|TxExecContext.AccumulatedMultiGas| UB[GrowBacklog]
        UB -->|for each constraint| WB[Weighted Update]
        WB -->|add weighted amount| MGC2[MultiGasConstraint]
    end

    subgraph SHRINK [Block End: ShrinkBacklog]
        TIME[timePassed * target] --> SB[ShrinkBacklog]
        SB -->|subtract capacity| MGC3[MultiGasConstraint]
    end

    style TX fill:#60a5fa,stroke:#3b82f6,color:#000
    style GROW fill:#f87171,stroke:#ef4444,color:#000
    style SHRINK fill:#4ade80,stroke:#22c55e,color:#000

Weighted Backlog Calculation

flowchart TD
    subgraph Input [Input]
        MG[MultiGas<br/>per-resource usage]
        W[Constraint Weights<br/>per-resource multiplier]
    end

    subgraph Calculation [Calculation]
        MG -->|amount| MUL[Multiply]
        W -->|weight| MUL
        MUL -->|saturating| WA[weightedAmount]
        WA -->|saturating add/sub| BL[totalBacklog]
    end

    subgraph Output [Output]
        BL --> SET[constraint.SetBacklog]
    end

    style Input fill:#fbbf24,stroke:#f59e0b,color:#000
    style Calculation fill:#c084fc,stroke:#a855f7,color:#000
    style Output fill:#4ade80,stroke:#22c55e,color:#000

System Test Validation

New logic has been validated by Nitro comparison system tests. The following 4 multi-gas specific tests were added to the passing list as part of this PR:

Test	What it validates
`TestSetAndGetGasPricingConstraints`	Single-gas constraint configuration round-trip
`TestSetAndGetMultiGasPricingConstraints`	Multi-gas constraint configuration round-trip
`TestMultiGasRefundForNormalTx`	Per-resource gas refund accounting for normal transactions
`TestMultiGasRefundForRetryableTx`	Per-resource gas refund accounting for retryable transactions

These tests run in comparison mode against Nitro, validating state root parity at every block.

Total passing comparison tests: 46 (see tools/comparison/passing-tests.txt).

Unit & Integration Tests

MultiGasConstraintTests.cs — Storage operations, backlog updates (including Nitro-mirrored weighted accumulation tests)
MultiGasFeesTests.cs — Fee commit workflow
PricingModelMultiGasTests.cs — Pricing model equivalence tests
L2PricingStateTests.cs — Constraint lifecycle, exponent calculation

Dependencies

PR	Repository	Description
#10765	nethermind	Submodule changes: `IResettableBlockTree`, MultiGas gas tracking in EVM
#723	nethermind-arbitrum	MultiGas tracking fixes and comparison mode isolation (merged into this PR)

codecov · 2026-03-03T11:01:21Z

Codecov Report

❌ Patch coverage is 65.71429% with 264 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.69%. Comparing base (03b251e) to head (69cba3f).

Files with missing lines	Patch %	Lines
...rmind.Arbitrum/Core/ResettableArbitrumBlockTree.cs	0.00%	87 Missing ⚠️
src/Nethermind.Arbitrum/Precompiles/ArbOwner.cs	0.00%	42 Missing ⚠️
...Arbitrum/Execution/ArbitrumTransactionProcessor.cs	42.55%	25 Missing and 2 partials ⚠️
src/Nethermind.Arbitrum/ArbitrumPlugin.cs	34.61%	16 Missing and 1 partial ⚠️
....Arbitrum/Rpc/ReceiptForRpcPolymorphicConverter.cs	0.00%	14 Missing ⚠️
...rbitrum/Genesis/ArbitrumGenesisStateInitializer.cs	45.45%	9 Missing and 3 partials ⚠️
src/Nethermind.Arbitrum/Arbos/ArbosState.cs	23.07%	9 Missing and 1 partial ⚠️
...rbitrum/Arbos/Storage/FilteredTransactionsState.cs	0.00%	10 Missing ⚠️
...mind.Arbitrum/Precompiles/Parser/ArbOwnerParser.cs	25.00%	9 Missing ⚠️
.../Nethermind.Arbitrum/Precompiles/ArbRetryableTx.cs	60.00%	4 Missing and 2 partials ⚠️
... and 12 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #700      +/-   ##
==========================================
- Coverage   76.11%   75.69%   -0.43%     
==========================================
  Files         234      241       +7     
  Lines       14150    14724     +574     
  Branches     2137     2223      +86     
==========================================
+ Hits        10770    11145     +375     
- Misses       2626     2806     +180     
- Partials      754      773      +19

Files with missing lines	Coverage Δ
src/Nethermind.Arbitrum/Arbos/ArbosAddresses.cs	`100.00% <100.00%> (ø)`
src/Nethermind.Arbitrum/Arbos/ArbosSubspaceIDs.cs	`100.00% <100.00%> (ø)`
src/Nethermind.Arbitrum/Arbos/Precompiles.cs	`100.00% <100.00%> (ø)`
...thermind.Arbitrum/Arbos/Programs/StylusPrograms.cs	`73.31% <100.00%> (ø)`
src/Nethermind.Arbitrum/Arbos/Programs/WasmGas.cs	`87.69% <100.00%> (ø)`
...Nethermind.Arbitrum/Arbos/Storage/GasConstraint.cs	`100.00% <100.00%> (ø)`
...rmind.Arbitrum/Arbos/Storage/MultiGasConstraint.cs	`100.00% <100.00%> (ø)`
.../Nethermind.Arbitrum/Arbos/Storage/MultiGasFees.cs	`100.00% <100.00%> (ø)`
...ethermind.Arbitrum/Arbos/Storage/RetryableState.cs	`98.33% <100.00%> (ø)`
src/Nethermind.Arbitrum/Config/ArbitrumConfig.cs	`91.42% <100.00%> (+0.25%)`	⬆️
... and 35 more

... and 2 files with indirect coverage changes

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Copilot

Pull request overview

Implements ArbOS 60 multi-gas constraints pricing with per-resource weighted backlogs and per-resource base fees, and wires it into transaction processing and pricing updates.

Changes:

Added storage-backed MultiGasConstraint and MultiGasFees primitives for ArbOS 60+ multi-dimensional pricing.
Updated L2PricingState to select a GasModel, update multi-gas backlogs/exponents, and commit per-resource fees.
Integrated multi-gas backlog growth in tx processing and added extensive tests across pricing, storage, and precompile-related behaviors.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
src/Nethermind.Arbitrum/Math/MathExtensions.cs	Adds inlining hints for saturating arithmetic helpers used by backlog math.
src/Nethermind.Arbitrum/Execution/ArbitrumTransactionProcessor.cs	Routes gas pool/backlog updates by `GasModel`, wiring multi-gas growth.
src/Nethermind.Arbitrum/Evm/MultiGas.cs	Adds `CheckResourceKind` helper and adjusts docs.
src/Nethermind.Arbitrum/Evm/ArbitrumGasPolicy.cs	Tracks code deposit under `StorageGrowth` for multi-gas accounting.
src/Nethermind.Arbitrum/Arbos/Storage/MultiGasFees.cs	New storage struct for next/current per-resource base fees with commit rotation.
src/Nethermind.Arbitrum/Arbos/Storage/MultiGasConstraint.cs	New storage struct for weighted multi-resource constraints and weighted backlog updates.
src/Nethermind.Arbitrum/Arbos/Storage/L2PricingState.cs	Core pricing/state changes: `GasModel`, multi-gas exponent calc, fee update/commit, backlog routing.
src/Nethermind.Arbitrum/Arbos/Storage/GasConstraint.cs	Cleans up storage clearing via new `Clear()` methods; makes class sealed.
src/Nethermind.Arbitrum/Arbos/Storage/ArbosStorage.cs	Adds `Clear()` to slot and storage-backed primitives.
src/Nethermind.Arbitrum/Arbos/ArbosVersion.cs	Introduces version 60 constants / alias for multi-gas constraints enablement.
src/Nethermind.Arbitrum.Test/Precompiles/PrecompileContextTests.cs	Adds tests for multi-gas tracking (some currently don’t exercise production code).
src/Nethermind.Arbitrum.Test/Precompiles/ConstraintsPrecompileTests.cs	Adds tests around configuring and using multi-gas constraints.
src/Nethermind.Arbitrum.Test/Infrastructure/ArbosStateTestExtensions.cs	Adds test-only helpers for reading/writing multi-gas fees.
src/Nethermind.Arbitrum.Test/Evm/MultiGasTests.cs	Adds tests for `CheckResourceKind` validation behavior.
src/Nethermind.Arbitrum.Test/Arbos/Storage/L2PricingStateTests.cs	Expands test coverage for gas model selection, backlog updates, multi-gas pricing, and guards.
src/Nethermind.Arbitrum.Test/Arbos/L2Pricing/PricingModelMultiGasTests.cs	Adds equivalence tests across legacy/single/multi-gas models.
src/Nethermind.Arbitrum.Test/Arbos/L2Pricing/MultiGasFeesTests.cs	Adds tests for per-resource fees and commit semantics.
src/Nethermind.Arbitrum.Test/Arbos/L2Pricing/MultiGasConstraintTests.cs	Adds tests for weighted backlog math and storage behavior.
src/Nethermind.Arbitrum.Test/Arbos/ArbosStorageTests.BackedByType.cs	Adds tests for new `Clear()` methods on storage-backed primitives.
src/Nethermind	Updates submodule pointer.

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wurdum

Please add integration tests to make sure e2e compatibility with nitro

AnkushinDaniil · 2026-03-04T15:17:15Z

Please add integration tests to make sure e2e compatibility with nitro

Added more tests. The next step in my plan is to adopt system tests

Copilot · 2026-03-05T09:12:07Z

@AnkushinDaniil I've opened a new pull request, #712, to work on those changes. Once the pull request is ready, I'll request review from you.

svlachakis · 2026-03-05T13:28:45Z

I would wait for system tests inclusion for better stability and assurance. I don't think there is any reason to rush this..my humble opinion.

Add ArbOS 60 multi-gas constraints with per-resource weights: - MultiGasConstraint: storage-backed constraint with weighted resources - MultiGasFees: per-resource base fee storage (next-block/current-block) - L2PricingState: constraint management, exponent calculation, pricing updates - GasModel enum for routing: Legacy, SingleGasConstraints, MultiGasConstraints - Input validation and bounds checking throughout

- Add Clear() to storage-backed types (ArbosStorageSlot, ArbosStorageBackedUInt/ULong/UInt256) - Add MultiGas.CheckResourceKind() validation for defensive programming - Throw InvalidOperationException on divisor == 0 instead of silent continue - Move test-only methods to test project via extension methods - Move weights dictionary inside loop to match reference implementation

In ArbOS 60+ (multi-gas constraints), BacklogUpdateCost returns a static cost (StorageReadCost + StorageWriteCost) regardless of constraint count. The C# implementation was missing this early return and continued with additional overhead calculations. Added tests to verify the static cost behavior in ArbOS 60 and the dynamic cost calculation in ArbOS 51.

…ization Performance improvements for multi-gas constraints implementation: - Add [AggressiveInlining] to SaturateMul and SaturateSub for consistency with SaturateAdd (MathExtensions.cs) - Seal leaf classes (MultiGasConstraint, GasConstraint, MultiGasFees, L2PricingState) to enable JIT devirtualization - Replace yield iterator in CalcMultiGasConstraintsExponents with direct loop to avoid state machine allocation per-call - Use inline array FeeBuffer instead of heap-allocated UInt256[] in MultiDimensionalPriceForRefund to eliminate per-transaction allocation

Add 24 tests to achieve full patch coverage: - Exception guards: divisor-zero checks in CalcMultiGasConstraintsExponents and UpdatePricingModelMultiConstraints - Migration path: SetMultiGasConstraintsFromSingleGasConstraints conversion, uint32 clamping, and clearing existing constraints - Legacy pricing: GasPoolUpdateCost for ArbOS 49/50, legacy backlog grow/shrink, high backlog pricing - Multi-gas fees: CommitMultiGasFees early return and commit paths, L1Calldata/zero fee fallback to baseFeeWei - MultiGas: CheckResourceKind validation for valid and invalid kinds - ArbosStorage: Clear methods for UInt, ULong, UInt256 backed storage

Remove ShouldUseGasConstraints() which was a C#-only helper that didn't exist in Nitro. Use GetGasModelToUse() directly instead, which matches Nitro's GasModelToUse() function. Changes: - Remove ShouldUseGasConstraints() from L2PricingState - Update tests to use GetGasModelToUse() assertions - Remove tests that directly tested the removed method

…sPool UpdateGasPool now routes to GrowBacklog for ArbOS 60+ MultiGasConstraints mode, matching Nitro's tx_processor behavior. Legacy and SingleGasConstraints modes continue using AddToGasPool. Added tests mirroring Nitro's TestMultiGasConstraintBacklogGrowth and TestMultiGasConstraintBacklogDecay patterns for weighted accumulation.

Remove Arrange/Act/Assert comments from ConstraintsPrecompileTests and PrecompileContextTests per code style guidelines.

wurdum · 2026-03-25T20:17:13Z

Well done. Figuring out where to put all these CommitMultiGasFees is crazy 🤯

…pport The IJsonTypeInfoResolver approach (da1ebcb) broke polymorphic serialization — ArbitrumReceiptForRpc properties (GasUsedForL1, MultiGasUsed) were not serialized in comparison mode responses. Revert to a custom JsonConverter<ReceiptForRpc> that delegates to the runtime type, restoring correct receipt comparison.

- Remove unused `spec` variable in ArbitrumBlockProducer - Replace `var` with explicit types (ReceiptForRpcPolymorphicConverter, TestArbosStorage) - Introduce DisabledArbOsVersionOverride and make IArbOSVersionOverride required - Split L2PricingStateTests into partial classes by feature area

wurdum · 2026-05-18T09:56:08Z

FYI: Looks like folks in OffchainLabs changed the list of multi-gas resources
https://github.com/OffchainLabs/go-ethereum/blob/v3.10.x-release/arbitrum/multigas/resources.go#L18

damian-orzechowski · 2026-05-19T13:51:39Z

FYI: Looks like folks in OffchainLabs changed the list of multi-gas resources https://github.com/OffchainLabs/go-ethereum/blob/v3.10.x-release/arbitrum/multigas/resources.go#L18

Updated with changes from: OffchainLabs/go-ethereum#636

…com/NethermindEth/nethermind-arbitrum into daniil/arbos60-multigas-constraints

AnkushinDaniil force-pushed the daniil/arbos60-multigas-constraints branch 6 times, most recently from c1c7363 to f338aff Compare March 3, 2026 10:58

AnkushinDaniil marked this pull request as ready for review March 3, 2026 15:15

Copilot AI review requested due to automatic review settings March 3, 2026 15:15

AnkushinDaniil requested review from damian-orzechowski, hudem1, svlachakis and wurdum as code owners March 3, 2026 15:15

Copilot AI reviewed Mar 3, 2026

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wurdum previously approved these changes Mar 4, 2026

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AnkushinDaniil force-pushed the daniil/arbos60-multigas-constraints branch 3 times, most recently from d900d77 to f55414e Compare March 4, 2026 15:26

Copilot AI mentioned this pull request Mar 5, 2026

Move divisor zero-check immediately before division in L2PricingState #712

Merged

AnkushinDaniil added 8 commits March 10, 2026 13:53

style: remove AAA comments from test files

538d114

Remove Arrange/Act/Assert comments from ConstraintsPrecompileTests and PrecompileContextTests per code style guidelines.

AnkushinDaniil added 2 commits March 26, 2026 15:19

wurdum mentioned this pull request May 8, 2026

[ArbOS 60] Multi-Gas Pricing Constraints #874

Closed

damian-orzechowski added 4 commits May 14, 2026 14:32

Merge main, update precompiles, update submodule and fixes

8d4daa4

Merge main

e8145b7

Fixes

3da5b68

Submodule update

ee5c2a8

Separate access read and write

2daa3fc

damian-orzechowski added 4 commits May 19, 2026 15:52

Merge main

e604bc0

Update submodule and fixes

2f189a5

Merge main

2a624c4

Update submodule

898439b

github-advanced-security AI found potential problems May 21, 2026

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wurdum reviewed May 21, 2026

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Comment thread src/Nethermind.Arbitrum/Precompiles/ArbRetryableTx.cs Outdated

wurdum reviewed May 21, 2026

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Comment thread src/Nethermind.Arbitrum/Precompiles/ArbRetryableTx.cs Outdated

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Comment thread src/Nethermind.Arbitrum/Arbos/Storage/L2PricingState.cs

wurdum reviewed May 21, 2026

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Comment thread src/Nethermind.Arbitrum/Evm/MultiGas.cs Outdated

damian-orzechowski and others added 3 commits May 22, 2026 13:23

Rename L1CallData resourcekind to Single Dimention

21db15d

More tests for multi-gas constraints, applying smaller review comments

99c1950

Merge branch 'main' into daniil/arbos60-multigas-constraints

dd8e3eb

damian-orzechowski requested a review from wurdum May 22, 2026 14:15

wurdum approved these changes May 22, 2026

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hudem1 approved these changes May 25, 2026

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Comment thread src/Nethermind.Arbitrum/Config/IArbitrumConfig.cs

Comment thread src/Nethermind.Arbitrum/Execution/ArbitrumBlockProcessor.cs

Comment thread src/Nethermind.Arbitrum/Execution/ArbitrumBlockValidationTransactionsExecutor.cs Outdated

damian-orzechowski added 2 commits May 25, 2026 11:40

Review comments

cc9abf8

Merge branch 'daniil/arbos60-multigas-constraints' of https://github.…

69cba3f

…com/NethermindEth/nethermind-arbitrum into daniil/arbos60-multigas-constraints

damian-orzechowski merged commit 7720aac into main May 25, 2026
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damian-orzechowski deleted the daniil/arbos60-multigas-constraints branch May 25, 2026 12:02

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Summary

Key Features

Architecture

Gas Model Selection

Storage Layout

Pricing Update Flow (Per Block)

Transaction Gas Tracking

Weighted Backlog Calculation

System Test Validation

Unit & Integration Tests

Dependencies

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