Precompiles for Multi-Dimensional Multi-Constraint Pricer

Author: MishkaRogachev

ArbGasInfo.sol

@@ -4,6 +4,8 @@
 
 pragma solidity >=0.4.21 <0.9.0;
 
+import {ArbMultiGasConstraintsTypes} from "./ArbMultiGasConstraintsTypes.sol";
+
 /// @title Provides insight into the cost of using the chain.
 /// @notice These methods have been adjusted to account for Nitro's heavy use of calldata compression.
 /// Of note to end-users, we no longer make a distinction between non-zero and zero-valued calldata bytes.
@@ -141,4 +143,21 @@ interface ArbGasInfo {
     /// @return constraints Array of triples (gas_target_per_second, adjustment_window_seconds, backlog)
     /// @notice Available in ArbOS version 50 and above.
     function getGasPricingConstraints() external view returns (uint64[3][] memory constraints);
+
+    /// @notice Get the current multi-gas pricing constraints used by the multi-dimensional multi-constraint pricing model.
+    /// @notice Each constraint includes its target throughput, adjustment window, backlog, and weighted resource configuration.
+    ///
+    /// @notice The array contains one `ResourceConstraint` struct per active constraint.
+    /// @notice Each constraint provides the following fields:
+    ///         - `resources`: list of (resource kind, weight) pairs (see the ArbMultiGasConstraintsTypes library for definitions)
+    ///         - `adjustmentWindowSecs`: time window (seconds) over which the price rises by a factor of e if demand is 2x the target (uint64, seconds)  
+    ///         - `targetPerSec`: target gas usage per second for this constraint (uint64, gas/sec)  
+    ///         - `backlog`: current backlog value for this constraint (uint64, gas units)
+    /// @return constraints Array of `ResourceConstraint` structs representing the current multi-gas pricing configuration.
+    /// @notice Available in ArbOS version 60 and above.
+    /// @notice See the `ArbMultiGasConstraintsTypes` library for struct definitions and field details.
+    function getMultiGasPricingConstraints()
+        external
+        view
+        returns (ArbMultiGasConstraintsTypes.ResourceConstraint[] memory constraints);
 }

ArbMultiGasConstraintsTypes.sol

@@ -0,0 +1,45 @@
+// Copyright 2025, Offchain Labs, Inc.
+// For license information, see https://github.com/OffchainLabs/nitro-contracts/blob/main/LICENSE
+// SPDX-License-Identifier: BUSL-1.1
+
+pragma solidity >=0.4.21 <0.9.0;
+
+/// @title ArbMultiGasConstraintsTypes
+/// @notice Type definitions for configuring and inspecting multi-dimensional gas pricing constraints.
+/// @dev These structures are shared by the `ArbOwner` and `ArbGasInfo` precompiles.
+library ArbMultiGasConstraintsTypes {
+
+    /// @notice Enumerates the distinct resource kinds used for multi-dimensional gas accounting.
+    /// @dev The numeric values of this enum must remain consistent with the corresponding
+    /// @dev The values defined here must stay synchronized with `go-ethereum/arbitrum/multigas/resources.go`.
+    enum ResourceKind {
+        Unknown,
+        Computation,
+        HistoryGrowth,
+        StorageAccess,
+        StorageGrowth,
+        L1Calldata,
+        L2Calldata,
+        WasmComputation
+    }
+
+    /// @notice Defines the relative contribution of a specific resource type within a constraint.
+    /// @param resource  The resource kind being weighted.
+    /// @param weight    The proportional weight that determines this resource kind’s influence on backlog growth.
+    struct WeightedResource {
+        ResourceKind resource;
+        uint64 weight;
+    }
+
+    /// @notice Describes a single pricing constraint that applies to one or more weighted resources.
+    /// @param resources             The list of weighted resources that participate in this constraint.
+    /// @param adjustmentWindowSecs  Time window (seconds) over which the price rises by a factor of e if demand is 2x the target (uint64, seconds)
+    /// @param targetPerSec          The target gas usage per second for this constraint (uint64, gas/sec).
+    /// @param backlog               The current or initial backlogfor this constraint (uint64, gas units).
+    struct ResourceConstraint {
+        WeightedResource[] resources;
+        uint32 adjustmentWindowSecs;
+        uint64 targetPerSec;
+        uint64 backlog;
+    }
+}

ArbOwner.sol

@@ -4,6 +4,8 @@
 
 pragma solidity >=0.4.21 <0.9.0;
 
+import {ArbMultiGasConstraintsTypes} from "./ArbMultiGasConstraintsTypes.sol";
+
 /**
  * @title Provides owners with tools for managing the rollup.
  * @notice Calls by non-owners will always revert.
@@ -302,6 +304,31 @@ interface ArbOwner {
         uint64[3][] calldata constraints
     ) external;
 
+    /// @notice Sets the list of multi-gas pricing constraints for the multi-dimensional multi-constraint pricing model.
+    /// @notice Replaces the existing configuration and initializes each constraint’s starting backlog value.
+    /// @notice Any previous multi-gas constraints are discarded.
+    ///
+    /// @notice This method defines both the target throughput and relative weights
+    /// @notice of each resource kind participating in multi-dimensional gas pricing.
+    /// @notice Each constraint may specify multiple resources with different weight multipliers.
+    /// @notice The final base fee is determined by the most congested resource dimension.
+    ///
+    /// @notice Model selection:
+    /// @notice - If one or more multi-gas constraints are provided, ArbOS switches to the multi-dimensional
+    /// @notice   pricing model and uses exactly the provided parameters.
+    /// @notice - If zero constraints are provided, the chain reverts to the previous pricing model
+    /// @notice   (either the single-constraint or single-dimensional multi-constraint configuration).
+    ///
+    /// @notice Available in ArbOS version 60 and above.
+    /// @param constraints  Array of `ResourceConstraint` structs, each containing:
+    ///        - `resources`: list of (resource kind, weight) pairs (see the ArbMultiGasConstraintsTypes library for definitions)
+    ///        - `adjustmentWindowSecs`: time window (seconds) over which the price rises by a factor of e if demand is 2x the target (uint64, seconds)  
+    ///        - `targetPerSec`: target gas usage per second for this constraint (uint64, gas/sec)  
+    ///        - `backlog`: initial backlog value for this constraint  (uint64, gas units)
+    function setMultiGasPricingConstraints(
+        ArbMultiGasConstraintsTypes.ResourceConstraint[] calldata constraints
+    ) external;
+
     /// Emitted when a successful call is made to this precompile
     event OwnerActs(bytes4 indexed method, address indexed owner, bytes data);
 }