feat: Gas params

[rakita]

A way to configure all gas-related parameters in EVM so we can easily change dynamic part of gas of opcode.

[codspeed-hq]

CodSpeed Performance Report

Merging #3132 will degrade performances by 3.96%

_{Comparing rakita/gas-params (53141bd) with main (9afd166)}

Summary

❌ 2 regressions
✅ 171 untouched

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	transfer_finalize	17 µs	17.7 µs	-3.96%
❌	transfer	13.9 µs	14.5 µs	-3.92%

[rakita]

MCOPY has a static VERY_LOG gas

revm/crates/interpreter/src/instructions/memory.rs

Line 68 in d0bb48e

gas_or_fail!(context.interpreter, gas::copy_cost_verylow(len));

VERYLOW is 3gas.

revm/crates/interpreter/src/gas/calc.rs

Lines 110 to 111 in d0bb48e

	pub const fn copy_cost_verylow(len: usize) -> Option<u64> {
	copy_cost(VERYLOW, len)

[rakita]

revm/crates/interpreter/src/gas/constants.rs

Lines 7 to 8 in fdf606d

	pub const VERYLOW: u64 = 3;
	/// Gas cost for DATALOADN instruction.

[rakita]

moved to parent call here

https://github.com/bluealloy/revm/pull/3132/files#diff-67852b4107a0dfcff4283ce22ed74377355b616319ae786de7ff81284a9f679bL64-R68

[rakita]

Part of static gas

[rakita]

Frontier part as it has special logic is moved here:

revm/crates/interpreter/src/gas/params.rs

Lines 271 to 281 in 403f28f

	pub fn sstore_dynamic_gas(&self, is_istanbul: bool, vals: &SStoreResult, is_cold: bool) -> u64 {
	// frontier logic gets charged for every SSTORE operation if original value is zero.
	// this behaviour is fixed in istanbul fork.
	if !is_istanbul {
	if vals.is_present_zero() && !vals.is_new_zero() {
	return self.sstore_set_without_load_cost();
	} else {
	return self.sstore_reset_without_cold_load_cost();
	}
	}

This is without load cost that is now part of static instruction gas

[rakita]

is cold is now always added but cold cost is zero before berlin here:

revm/crates/interpreter/src/gas/params.rs

Lines 284 to 288 in 403f28f

	// this will be zero before berlin fork.
	if is_cold {
	gas += self.cold_storage_cost();
	}

[rakita]

This code is slighly changes as SLOAD_GAS is not part of the static instruction gas. So we have fewer branches

It is easy to follow commnets

revm/crates/interpreter/src/gas/params.rs

Lines 289 to 300 in 403f28f

	// if new values changed present value and present value is unchanged from original.
	if vals.new_values_changes_present() && vals.is_original_eq_present() {
	gas += if vals.is_original_zero() {
	// set cost for creating storage slot (Zero slot means it is not existing).
	// and previous condition says present is same as original.
	self.sstore_set_without_load_cost()
	} else {
	// if new value is not zero, this means we are setting some value to it.
	self.sstore_reset_without_cold_load_cost()
	};
	}
	gas

[rakita]

This is moved to a variable inside GasParams.

revm/crates/interpreter/src/gas/params.rs

Line 157 in 403f28f

table[GasId::sstore_static().as_usize()] = gas::WARM_STORAGE_READ_COST;

revm/crates/interpreter/src/gas/params.rs

Line 149 in 403f28f

table[GasId::sstore_static().as_usize()] = gas::ISTANBUL_SLOAD_GAS;

revm/crates/interpreter/src/gas/params.rs

Line 127 in 403f28f

table[GasId::sstore_static().as_usize()] = 5000;

[rakita]

Has become part of static instruction gas.

And additional gas is handled here:

revm/crates/interpreter/src/instructions/host.rs

Lines 193 to 210 in 403f28f

	pub fn sload<WIRE: InterpreterTypes, H: Host + ?Sized>(context: InstructionContext<'_, H, WIRE>) {
	popn_top!([], index, context.interpreter);
	let spec_id = context.interpreter.runtime_flag.spec_id();
	let target = context.interpreter.input.target_address();
	if spec_id.is_enabled_in(BERLIN) {
	let additional_cold_cost = context
	.interpreter
	.gas_params
	.cold_storage_additional_cost();
	let skip_cold = context.interpreter.gas.remaining() < additional_cold_cost;
	let res = context.host.sload_skip_cold_load(target, *index, skip_cold);
	match res {
	Ok(storage) => {
	if storage.is_cold {
	gas!(context.interpreter, additional_cold_cost);
	}

[rakita]

Dynamic part is in GasParams here:

revm/crates/interpreter/src/gas/params.rs

Lines 193 to 201 in 403f28f

	pub fn exp_cost(&self, power: U256) -> u64 {
	if power.is_zero() {
	return 0;
	}
	// EIP-160: EXP cost increase
	self.get(GasId::exp_byte_gas())
	.saturating_mul(log2floor(power) / 8 + 1)
	}

revm/crates/interpreter/src/gas/params.rs

Lines 144 to 147 in 403f28f

	if spec.is_enabled_in(SpecId::SPURIOUS_DRAGON) {
	table[GasId::exp_byte_gas().as_usize()] = 50;
	}

revm/crates/interpreter/src/gas/params.rs

Lines 110 to 111 in 403f28f

	table[GasId::exp_byte_gas().as_usize()] = 10;
	table[GasId::logdata().as_usize()] = gas::LOGDATA;

And static part (EXP) is now part of static instruction gas

[rakita]

Fully moved to:

revm/crates/interpreter/src/gas/params.rs

Lines 399 to 405 in 403f28f

	pub fn create2_cost(&self, len: usize) -> u64 {
	self.get(GasId::create()).saturating_add(
	self.get(GasId::keccak256_per_word())
	.saturating_mul(num_words(len) as u64),
	)
	}

revm/crates/interpreter/src/gas/params.rs

Line 120 in 403f28f

table[GasId::create().as_usize()] = gas::CREATE;

revm/crates/interpreter/src/gas/params.rs

Line 116 in 403f28f

table[GasId::keccak256_per_word().as_usize()] = gas::KECCAK256WORD;

[rakita]

before instanbul is moved here:

revm/crates/interpreter/src/gas/params.rs

Lines 305 to 316 in 403f28f

	pub fn sstore_refund(&self, is_istanbul: bool, vals: &SStoreResult) -> i64 {
	// EIP-3529: Reduction in refunds
	let sstore_clearing_slot_refund = self.sstore_clearing_slot_refund() as i64;
	if !is_istanbul {
	// // before istanbul fork, refund was always awarded without checking original state.
	if !vals.is_present_zero() && vals.is_new_zero() {
	return sstore_clearing_slot_refund;
	}
	return 0;
	}

[rakita]

part where we return zero is now here

revm/crates/interpreter/src/gas/params.rs

Lines 317 to 321 in 403f28f

	// If current value equals new value (this is a no-op)
	if vals.is_new_eq_present() {
	return 0;
	}

[rakita]

This part is not refactored here

revm/crates/interpreter/src/gas/params.rs

Lines 322 to 327 in 403f28f

	// refund for the clearing of storage slot.
	// As new is not equal to present, new values zero means that original and present values are not zero
	if vals.is_original_eq_present() && vals.is_new_zero() {
	return sstore_clearing_slot_refund;
	}

[rakita]

And last part is now here. Added additional comments from EIP

revm/crates/interpreter/src/gas/params.rs

Lines 328 to 355 in 403f28f

	let mut refund = 0;
	// If original value is not 0
	if !vals.is_original_zero() {
	// If current value is 0 (also means that new value is not 0),
	if vals.is_present_zero() {
	// remove SSTORE_CLEARS_SCHEDULE gas from refund counter.
	refund -= sstore_clearing_slot_refund;
	// If new value is 0 (also means that current value is not 0),
	} else if vals.is_new_zero() {
	// add SSTORE_CLEARS_SCHEDULE gas to refund counter.
	refund += sstore_clearing_slot_refund;
	}
	}
	// If original value equals new value (this storage slot is reset)
	if vals.is_original_eq_new() {
	// If original value is 0
	if vals.is_original_zero() {
	// add SSTORE_SET_GAS - SLOAD_GAS to refund counter.
	refund += self.sstore_set_without_load_cost() as i64;
	// Otherwise
	} else {
	// add SSTORE_RESET_GAS - SLOAD_GAS gas to refund counter.
	refund += self.sstore_reset_without_cold_load_cost() as i64;
	}
	}
	refund
	}

[Copilot]

Pull Request Overview

This PR introduces a configurable gas parameters system (GasParams) for the EVM interpreter, enabling easy modification of dynamic gas costs for opcodes. The implementation replaces hardcoded gas calculations with a flexible, spec-aware table-based approach.

Key Changes:

• Introduced GasParams struct with gas cost table that adapts based on EVM spec version
• Refactored all instruction implementations to use GasParams instead of direct gas constant references
• Updated memory resize operations to accept and use GasParams
• Added gas parameter configuration in handler initialization
• Enhanced test script with --keep-going flag support

Reviewed Changes

Copilot reviewed 28 out of 28 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
scripts/run-tests.sh	Added --keep-going flag support for continuing tests after failures
crates/interpreter/src/gas/params.rs	New core gas parameters implementation with configurable gas table
crates/interpreter/src/interpreter.rs	Integrated GasParams into interpreter struct and initialization
crates/interpreter/src/interpreter/shared_memory.rs	Updated memory resize to use GasParams and return Result
crates/interpreter/src/instructions/*.rs	Refactored all instruction gas calculations to use GasParams
crates/interpreter/src/gas/*.rs	Removed deprecated gas calculation functions, kept core utilities
crates/handler/src/*.rs	Updated handler to configure gas parameters based on spec
crates/context/src/journal/inner.rs	Minor type alias cleanup
crates/context/interface/src/context.rs	Added helper methods to SStoreResult

---

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[rakita]

Moved to:

revm/crates/interpreter/src/gas/params.rs

Lines 442 to 453 in 0ee23df

	/// New account cost. New account cost is added to the gas cost if the account is empty.
	#[inline]
	pub fn new_account_cost(&self, is_spurious_dragon: bool, transfers_value: bool) -> u64 {
	// EIP-161: State trie clearing (invariant-preserving alternative)
	// Pre-Spurious Dragon: always charge for new account
	// Post-Spurious Dragon: only charge if value is transferred
	if !is_spurious_dragon || transfers_value {
	return self.get(GasId::new_account_cost());
	}
	0
	}

[klkvr]

will this not work properly now for any impl overriding this trait? i don't think this is acceptable and we need to either hide this deeper or make it so this change is obvious from compilation issues after the bump

[klkvr]

can gas_params not be part of the Context?

this should allow us to avoid any changes to InstructionProvider and to the frame init logic which now propagate the GasParams quite deeply just to set the interpreter field while this is technically an externally provided context

it would also only retain the actual dynamic runtime data in Interpreter type

[klkvr]

this also makes me wonder if GasParams could be entirely hidden inside of the InstructionProvider? so that I just do something like EthInstructions::new(gas_params) and it produces an instruction table that uses my gas params?