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Refactor(benchmark): optimize storage access worst case #1813

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de6a6e4
refactor(zkevm): optimize legacy sstore/ssload operation
LouisTsai-Csie Jun 27, 2025
6b96e8a
refactor(zkevm): update linting issue
LouisTsai-Csie Jun 27, 2025
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92 changes: 49 additions & 43 deletions tests/zkevm/test_worst_stateful_opcodes.py
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Original file line number Diff line number Diff line change
Expand Up @@ -185,21 +185,26 @@ def test_worst_address_state_warm(
)


class StorageAction:
"""Enum for storage actions."""
class LoadAction:
"""Enum for sload actions."""

READ = 1
WRITE_SAME_VALUE = 2
WRITE_NEW_VALUE = 3


class StoreAction:
"""Enum for sstore actions."""

WRITE_SAME_VALUE = 1
WRITE_NEW_VALUE = 2


@pytest.mark.valid_from("Cancun")
@pytest.mark.parametrize(
"storage_action",
[
pytest.param(StorageAction.READ, id="SSLOAD"),
pytest.param(StorageAction.WRITE_SAME_VALUE, id="SSTORE same value"),
pytest.param(StorageAction.WRITE_NEW_VALUE, id="SSTORE new value"),
pytest.param(LoadAction.READ, id="SSLOAD"),
pytest.param(StoreAction.WRITE_SAME_VALUE, id="SSTORE same value"),
pytest.param(StoreAction.WRITE_NEW_VALUE, id="SSTORE new value"),
],
)
@pytest.mark.parametrize(
Expand All @@ -214,7 +219,7 @@ def test_worst_storage_access_cold(
blockchain_test: BlockchainTestFiller,
pre: Alloc,
fork: Fork,
storage_action: StorageAction,
storage_action: LoadAction | StoreAction,
absent_slots: bool,
):
"""Test running a block with as many cold storage slot accesses as possible."""
Expand All @@ -223,17 +228,17 @@ def test_worst_storage_access_cold(
attack_gas_limit = Environment().gas_limit

cost = gas_costs.G_COLD_SLOAD # All accesses are always cold
if storage_action == StorageAction.WRITE_NEW_VALUE:
if storage_action == StoreAction.WRITE_NEW_VALUE:
if not absent_slots:
cost += gas_costs.G_STORAGE_RESET
else:
cost += gas_costs.G_STORAGE_SET
elif storage_action == StorageAction.WRITE_SAME_VALUE:
elif storage_action == StoreAction.WRITE_SAME_VALUE:
if absent_slots:
cost += gas_costs.G_STORAGE_SET
else:
cost += gas_costs.G_WARM_SLOAD
elif storage_action == StorageAction.READ:
elif storage_action == LoadAction.READ:
cost += gas_costs.G_WARM_SLOAD

intrinsic_gas_cost_calc = fork.transaction_intrinsic_cost_calculator()
Expand All @@ -242,30 +247,29 @@ def test_worst_storage_access_cold(
blocks = []

# Contract code
execution_code_body = Bytecode()
if storage_action == StorageAction.WRITE_SAME_VALUE:
# All the storage slots in the contract are initialized to their index.
# That is, storage slot `i` is initialized to `i`.
execution_code_body = Op.SSTORE(Op.DUP1, Op.DUP1)
elif storage_action == StorageAction.WRITE_NEW_VALUE:
# The new value 2^256-1 is guaranteed to be different from the initial value.
execution_code_body = Op.SSTORE(Op.DUP2, Op.NOT(0))
elif storage_action == StorageAction.READ:
execution_code_body = Op.POP(Op.SLOAD(Op.DUP1))

execution_code = Op.PUSH4(num_target_slots) + While(
body=execution_code_body,
condition=Op.PUSH1(1) + Op.SWAP1 + Op.SUB + Op.DUP1 + Op.ISZERO + Op.ISZERO,
)
execution_code = Bytecode()

if isinstance(storage_action, LoadAction):
execution_code += sum(Op.SLOAD(i) for i in reversed(range(num_target_slots)))
elif isinstance(storage_action, StoreAction):
if storage_action == StoreAction.WRITE_SAME_VALUE:
# All the storage slots in the contract are initialized to their index.
# That is, storage slot `i` is initialized to `i`.
execution_code += sum(Op.SSTORE(i, i) for i in reversed(range(num_target_slots)))
elif storage_action == StoreAction.WRITE_NEW_VALUE:
# The new value 2^256-1 is guaranteed to be different from the initial value.
execution_code += sum(
Op.SSTORE(i, Op.NOT(0)) for i in reversed(range(num_target_slots))
)

execution_code_address = pre.deploy_contract(code=execution_code)

# Contract creation
slots_init = Bytecode()
if not absent_slots:
slots_init = Op.PUSH4(num_target_slots) + While(
body=Op.SSTORE(Op.DUP1, Op.DUP1),
condition=Op.PUSH1(1) + Op.SWAP1 + Op.SUB + Op.DUP1 + Op.ISZERO + Op.ISZERO,
)
slots_init = (
Bytecode()
if absent_slots
else Bytecode() + sum(Op.SSTORE(i, i) for i in reversed(range(num_target_slots)))
)

# To create the contract, we apply the slots_init code to initialize the storage slots
# (int the case of absent_slots=False) and then copy the execution code to the contract.
Expand Down Expand Up @@ -310,16 +314,17 @@ def test_worst_storage_access_cold(
@pytest.mark.parametrize(
"storage_action",
[
pytest.param(StorageAction.READ, id="SLOAD"),
pytest.param(StorageAction.WRITE_SAME_VALUE, id="SSTORE same value"),
pytest.param(StorageAction.WRITE_NEW_VALUE, id="SSTORE new value"),
pytest.param(LoadAction.READ, id="SLOAD"),
pytest.param(StoreAction.WRITE_SAME_VALUE, id="SSTORE same value"),
pytest.param(StoreAction.WRITE_NEW_VALUE, id="SSTORE new value"),
],
)
@pytest.mark.slow()
def test_worst_storage_access_warm(
blockchain_test: BlockchainTestFiller,
pre: Alloc,
storage_action: StorageAction,
storage_action: LoadAction | StoreAction,
fork: Fork,
):
"""Test running a block with as many warm storage slot accesses as possible."""
env = Environment(gas_limit=100_000_000_000)
Expand All @@ -332,16 +337,17 @@ def test_worst_storage_access_warm(

# Contract code
execution_code_body = Bytecode()
if storage_action == StorageAction.WRITE_SAME_VALUE:
if storage_action == StoreAction.WRITE_SAME_VALUE:
execution_code_body = Op.SSTORE(0, Op.DUP1)
elif storage_action == StorageAction.WRITE_NEW_VALUE:
execution_code_body = Op.PUSH1(1) + Op.ADD + Op.SSTORE(0, Op.DUP1)
elif storage_action == StorageAction.READ:
elif storage_action == StoreAction.WRITE_NEW_VALUE:
execution_code_body = Op.SSTORE(0, Op.NOT(0))
elif storage_action == LoadAction.READ:
execution_code_body = Op.POP(Op.SLOAD(0))

execution_code = Op.PUSH1(storage_slot_initial_value) + While(
body=execution_code_body,
)
calldata = Op.PUSH1(storage_slot_initial_value)
execution_code = code_loop_precompile_call(calldata, execution_code_body, fork)
assert len(execution_code) <= fork.max_code_size()

execution_code_address = pre.deploy_contract(code=execution_code)

creation_code = (
Expand Down
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