Performance issue for guest function: event_table.0.len() * EVENT_TABLE_ENTRY_ROWS <= self.max_available_rows

[medvedNick]

I'm not able to run pretty simple fibonacci guest function in zkWasm with reasonable performance, meaning I won't be able to run my custom tough app on it.

I've tried to launch that fibonacci program on zkWasm for n > 10000 and it always ends in assertion failed: event_table.0.len() * EVENT_TABLE_ENTRY_ROWS as usize <= self.max_available_rows). I've tried to increase k from default 18 up to 24 and more, and got the same error. For k=25 setup run for more than 20mins, btw.

I understand that wasm is a pretty complex case to zk-verify, but failing calculate fibonacci program means for me no production code could be run on zkWasm. Moreover, other zk-sokutions (such as risk-0) show much better performance. For instance, I'm able to generate proof for n=150000 in 2 mins and verify it for 5ms, compared to my best result with zkWasm with n=1000 with proof generation in 1.5 mins and verification in 170ms.

The question is - is there any way to run the full setup-proof-verify cycle for such a large n like 10000? Is there any parameter other than k which I can change?

Here is the guest function

extern "C" { 
    fn wasm_input(n: i32) -> i64;
    fn log_foreign(value: i64);
}

#[no_mangle]
pub extern "C" fn entrypoint() {
    let input: i32 = unsafe { wasm_input(1) } as i32;
    let f = fibonacci(input);
    unsafe { log_foreign(f as i64) };
}

pub fn fibonacci(n: i32) -> i32 {
    let (mut a, mut b) = (0, 1);
    for _ in 0..n {
        let c = a;
        a = b;
        b += c;
    }
    a
}

log_foreign is just a renamed method log added in register_log_foreign.

I've used methods same as cli uses and my host looks like this

fn main() {
    let n = 10000;
    let wasm_binary = fs::read("res/fib.wasm").expect("No wasm");
    let prefix = "zkwasm";
    let zkwasm_k = 24;
    let function_name = "entrypoint";
    let output_dir: PathBuf = "zk".into();

    let public_inputs: Vec<u64> = vec![n];
    let private_inputs: Vec<u64> = vec![];

    let proof_path: PathBuf = "zk/zkwasm.0.transcript.data".into();

    /////////// setup
    let start = std::time::Instant::now();

    let circuit = build_circuit_without_witness(&wasm_binary, function_name);

    let params = {
        let params_path = &output_dir.join(format!("K{}.params", zkwasm_k));
        load_or_build_unsafe_params::<Bn256>(zkwasm_k, Some(params_path))
    };
    {
        let vk_path = &output_dir.join(format!("{}.{}.vkey.data", prefix, 0));
        load_or_build_vkey::<Bn256, _>(&params, &circuit, Some(vk_path))
    };
    println!("setup time: {:?}", start.elapsed());


    /////////// proof
    let start = std::time::Instant::now();

    let circuit =
        build_circuit_with_witness(&wasm_binary, function_name, &public_inputs, &private_inputs).expect("=== Something went wrong");
    let mut public_inputs_fri = public_inputs
        .iter()
        .map(|v| Fr::from(*v))
        .collect::<Vec<_>>()
        .clone();

    let mut instances = vec![];
    instances.append(&mut public_inputs_fri);

    circuit.tables.write_json(Some(output_dir.clone()));

    let vkey = load_vkey::<Bn256, TestCircuit<_>>(
        &params,
        &output_dir.join(format!("{}.{}.vkey.data", prefix, 0)),
    );

    load_or_create_proof::<Bn256, _>(
        &params,
        vkey,
        circuit.clone(),
        &[&instances],
        Some(&output_dir.join(format!("{}.{}.transcript.data", prefix, 0))),
        TranscriptHash::Poseidon,
        false,
    );
    println!("proof time: {:?}", start.elapsed());


    /////////// dry run
    build_circuit_with_witness(&wasm_binary, function_name, &public_inputs, &private_inputs);

    /////////// verify
    let start = std::time::Instant::now();

    let public_inputs_size = public_inputs.len() + 1;
    let mut public_inputs_fri = public_inputs
        .iter()
        .map(|v| Fr::from(*v))
        .collect::<Vec<_>>()
        .clone();

    let instances = {
        let mut instances = vec![];
        instances.append(&mut public_inputs_fri);
        instances
    };
    let vkey = load_vkey::<Bn256, TestCircuit<_>>(
        &params,
        &output_dir.join(format!("{}.{}.vkey.data", prefix, 0)),
    );

    let proof = load_proof(&proof_path);
    let params_verifier: ParamsVerifier<Bn256> = params.verifier(public_inputs_size).unwrap();
    let strategy = SingleVerifier::new(&params_verifier);

    verify_proof(
        &params_verifier,
        &vkey,
        strategy,
        &[&[&instances]],
        &mut PoseidonRead::init(&proof[..]),
    )
    .expect("Something is incorrect noooooooo");

    println!("verify time: {:?}", start.elapsed());
}

I tried using both main and latest v2 branches of zkWasm with default features. I'm running these benchmarks on my M1 mac btw.

[xgaozoyoe]

You can specify k in cli in zkWASM
For example:
~/zkWasm/target/releae/cli -k 18 ....
Make sure that you use the same k for setup, proof, and batch.

[medvedNick]

@xgaozoyoe thats exactly what I was doing. As I've mentioned, increasing k from 18 to 24 did nothing, I get the same error anyway. If you look at my code closely, you'll notice that it is exactly the same as in cli

[xgaozoyoe]

I am not sure how you conclude that your code follows exactly the cli source code. My notice is that in cli we use the following:

let zkwasm_k = Self::parse_zkwasm_k_arg(&top_matches).unwrap_or(MIN_K);
set_zkwasm_k(zkwasm_k);

while set_zkwasm_k is implemented as following:
pub const MIN_K: u32 = 18;

lazy_static! {
static ref ZKWASM_K: Mutex =
Mutex::new(env::var("ZKWASM_K").map_or(MIN_K, |k| k.parse().unwrap()));
pub(super) static ref ZKWASM_TABLE_DENOMINATOR: u32 =
env::var("ZKWASM_TABLE_DENOMINATOR").map_or(32, |k| k.parse().unwrap());
static ref ZKWASM_ETABLE_RATIO: u32 =
env::var("ZKWASM_ETABLE_RATIO").map_or(31, |k| k.parse().unwrap());
static ref ZKWASM_MTABLE_RATIO: u32 =
env::var("ZKWASM_MTABLE_RATIO").map_or(31, |k| k.parse().unwrap());
static ref ZKWASM_JTABLE_RATIO: u32 =
env::var("ZKWASM_JTABLE_RATIO").map_or(31, |k| k.parse().unwrap());
static ref ZKWASM_BIT_TABLE_RATIO: u32 =
env::var("ZKWASM_BIT_TABLE_RATIO").map_or(31, |k| k.parse().unwrap());
pub(super) static ref ZKWASM_FOREIGN_CALL_TABLE_RATIO: u32 =
env::var("ZKWASM_FOREIGN_CALL_TABLE_RATIO").map_or(31, |k| k.parse().unwrap());
static ref ZKWASM_SHA256_RATIO: u32 =
env::var("ZKWASM_SHA256_RATIO").map_or(31, |k| k.parse().unwrap());
}

**_pub fn set_zkwasm_k(k: u32) {
assert!(k >= MIN_K);

let mut zkwasm_k = (*ZKWASM_K).lock().unwrap();
*zkwasm_k = k;

}_**

pub fn zkwasm_k() -> u32 {
*ZKWASM_K.lock().unwrap()
}

[xgaozoyoe]

But anyway, thank you very much for trying the codebase. Hope the above comment can help. If you can improve the way of setting k in the codebase, it will be great to have a patch and I am willing to apply it.

[xgaozoyoe]

You can also submit wasm image on https://zkwasm-explorer.delphinuslab.com/ for reporting performance issues with certain wasm image.