Fix benchmarks

[ed255]

In https://github.com/privacy-scaling-explorations/zkevm-circuits/tree/main/circuit-benchmarks/src we have a series of tests to build a proof of each subcircuit to get benchmark results.
These benchmarks have been broken for a while and need to be fixed.

Example:

$ DEGREE=10 cargo test --features=benches state_circuit::tests::bench_state_circuit_prover
warning: `zkevm-circuits` (lib) generated 1 warning
    Finished test [unoptimized + debuginfo] target(s) in 0.23s
     Running unittests src/lib.rs (/mnt/data/dev/git/zkevm/zkevm-circuits/target/debug/deps/circuit_benchmarks-6d442a10c45f553e)

running 1 test
test state_circuit::tests::bench_state_circuit_prover ... FAILED

failures:

---- state_circuit::tests::bench_state_circuit_prover stdout ----
Start:   State Circuit [Setup generation] with degree = 10
End:     State Circuit [Setup generation] with degree = 10 .........................1.323s
thread 'state_circuit::tests::bench_state_circuit_prover' panicked at 'keygen_vk should not fail: NotEnoughRowsAvailable { current_k: 10 }', circuit-benchmarks/src/state_circuit.rs:58:61
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    state_circuit::tests::bench_state_circuit_prover

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 9 filtered out; finished in 1.33s

error: test failed, to rerun pass `--lib`

[zemse]

Since StateCircuit uses the U16 table, it seems to me that the degree should have to be at least 16. Should the fix simply add a minimum default value for the DEGREE env similar to other tests?

How are the benchmark tests triggered? Is it run individually passing in the DEGREE manually or using cargo test inside circuit-benchmarks?

circuit-benchmarks $ cargo test --features=benches

[ed255]

Since StateCircuit uses the U16 table, it seems to me that the degree should have to be at least 16. Should the fix simply add a minimum default value for the DEGREE env similar to other tests?

That makes sense. Your suggestion would be a possible solution. Another solution that comes to my mind is to just check if DEGREE is >= 16 for the StateCircuit benchmark, and if not panic early with a message. Also the same process should be done for the other benchmakrs: check if the other circuits have a minimum degree, and either panic with a useful message when degree is lower, and/or set a default degree that is the minimum.

How are the benchmark tests triggered? Is it run individually passing in the DEGREE manually or using cargo test inside circuit-benchmarks?

circuit-benchmarks $ cargo test --features=benches

You can trigger them with this command from the circuit-benchmarks directory:

DEGREE=10 cargo test --features=benches state_circuit::tests

You can replace state_circuit by any of the implemented benchmarks which are:

• bytecode_circuit
• copy_circuit
• evm_circuit
• exp_circuit
• mpt_circuit
• packed_multi_keccak
• pi_circuit
• state_circuit
• super_circuit
• tx_circuit

[ChihChengLiang]

Assign this task to @zemse