test_worst_precompile_only_data_input()

Documentation for tests/zkevm/test_worst_compute.py::test_worst_precompile_only_data_input@64f949d0.

Generate fixtures for these test cases for Prague with:

fill -v tests/zkevm/test_worst_compute.py::test_worst_precompile_only_data_input --fork Prague

Test running a block with as many precompile calls which have a single data input.

Source code in tests/zkevm/test_worst_compute.py

@pytest.mark.valid_from("Cancun")
@pytest.mark.parametrize(
    "address,static_cost,per_word_dynamic_cost,bytes_per_unit_of_work",
    [
        pytest.param(0x02, 60, 12, 64, id="SHA2-256"),
        pytest.param(0x03, 600, 120, 64, id="RIPEMD-160"),
        pytest.param(0x04, 15, 3, 1, id="IDENTITY"),
    ],
)
@pytest.mark.slow()
def test_worst_precompile_only_data_input(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
    address: Address,
    static_cost: int,
    per_word_dynamic_cost: int,
    bytes_per_unit_of_work: int,
):
    """Test running a block with as many precompile calls which have a single `data` input."""
    env = Environment()

    # Intrinsic gas cost is paid once.
    intrinsic_gas_calculator = fork.transaction_intrinsic_cost_calculator()
    available_gas = env.gas_limit - intrinsic_gas_calculator()

    gsc = fork.gas_costs()
    mem_exp_gas_calculator = fork.memory_expansion_gas_calculator()

    # Discover the optimal input size to maximize precompile work, not precompile calls.
    max_work = 0
    optimal_input_length = 0
    for input_length in range(1, 1_000_000, 32):
        parameters_gas = (
            gsc.G_BASE  # PUSH0 = arg offset
            + gsc.G_BASE  # PUSH0 = arg size
            + gsc.G_BASE  # PUSH0 = arg size
            + gsc.G_VERY_LOW  # PUSH0 = arg offset
            + gsc.G_VERY_LOW  # PUSHN = address
            + gsc.G_BASE  # GAS
        )
        iteration_gas_cost = (
            parameters_gas
            + +static_cost  # Precompile static cost
            + math.ceil(input_length / 32) * per_word_dynamic_cost  # Precompile dynamic cost
            + gsc.G_BASE  # POP
        )
        # From the available gas, we subtract the mem expansion costs considering we know the
        # current input size length.
        available_gas_after_expansion = max(
            0, available_gas - mem_exp_gas_calculator(new_bytes=input_length)
        )
        # Calculate how many calls we can do.
        num_calls = available_gas_after_expansion // iteration_gas_cost
        total_work = num_calls * math.ceil(input_length / bytes_per_unit_of_work)

        # If we found an input size that is better (reg permutations/gas), then save it.
        if total_work > max_work:
            max_work = total_work
            optimal_input_length = input_length

    calldata = Op.CODECOPY(0, 0, optimal_input_length)
    attack_block = Op.POP(Op.STATICCALL(Op.GAS, address, 0, optimal_input_length, 0, 0))
    code = code_loop_precompile_call(calldata, attack_block, fork)

    code_address = pre.deploy_contract(code=code)

    tx = Transaction(
        to=code_address,
        gas_limit=env.gas_limit,
        sender=pre.fund_eoa(),
    )

    state_test(
        env=env,
        pre=pre,
        post={},
        tx=tx,
    )

Parametrized Test Cases

The interactive table below is also available as a standalone page.

Fork All Forks Cancun Prague Osaka

Fixture Type All Fixture Types state_test blockchain_test

Test ID (Abbreviated)	address	static_cost	per_word_dynamic_cost	bytes_per_unit_of_work
...fork_Cancun-state_test-SHA2-256	2	60	12	64
...fork_Cancun-state_test-RIPEMD-160	3	600	120	64
...fork_Cancun-state_test-IDENTITY	4	15	3	1
...fork_Cancun-blockchain_test_from_state_test-SHA2-256	2	60	12	64
...fork_Cancun-blockchain_test_from_state_test-RIPEMD-160	3	600	120	64
...fork_Cancun-blockchain_test_from_state_test-IDENTITY	4	15	3	1
...fork_Prague-state_test-SHA2-256	2	60	12	64
...fork_Prague-state_test-RIPEMD-160	3	600	120	64
...fork_Prague-state_test-IDENTITY	4	15	3	1
...fork_Prague-blockchain_test_from_state_test-SHA2-256	2	60	12	64
...fork_Prague-blockchain_test_from_state_test-RIPEMD-160	3	600	120	64
...fork_Prague-blockchain_test_from_state_test-IDENTITY	4	15	3	1
...fork_Osaka-state_test-SHA2-256	2	60	12	64
...fork_Osaka-state_test-RIPEMD-160	3	600	120	64
...fork_Osaka-state_test-IDENTITY	4	15	3	1
...fork_Osaka-blockchain_test_from_state_test-SHA2-256	2	60	12	64
...fork_Osaka-blockchain_test_from_state_test-RIPEMD-160	3	600	120	64
...fork_Osaka-blockchain_test_from_state_test-IDENTITY	4	15	3	1