add_change_if_needed very slow

[YFrendo]

Hy everyone.

I try to implement the Nami Wallet on one of my website and so I use this library to generate transaction.
I have a performance issue with the function add_change_if_needed(), it took 50sc to be execute on google chrome.
The transaction is very simple :send X ADA to one address.
I'm using the 9.1.0 version full JS.
Here some code:

async function pay(addr, adaAmount){
    const cardano = window.cardano
    const protocolParameters = await getProtocolParameters()
    const lovelace = (parseFloat(adaAmount) * 1000000).toString()

    var ByteAddress = await window.cardano.getUsedAddresses();
    const paymentAddr = await S.Address.from_bytes(fromHex(ByteAddress[0])).to_bech32(); 

    const rawUtxo = await cardano.getUtxos()
    const utxos = rawUtxo.map(u => S.TransactionUnspentOutput.from_bytes(fromHex(u)))
    const outputs = S.TransactionOutputs.new()

    outputs.add(
        S.TransactionOutput.new(
            S.Address.from_bech32(addr),
            S.Value.new(
                S.BigNum.from_str(lovelace)
            )
        )
    )
    const output = S.TransactionOutput.new(
      S.Address.from_bech32(addr),
      S.Value.new(
          S.BigNum.from_str(lovelace)
      )
  )

    CoinSelection.setProtocolParameters(
        protocolParameters.minUtxo.to_str(),
        protocolParameters.linearFee.coefficient().to_str(),
        protocolParameters.linearFee.constant().to_str(),
        protocolParameters.maxTxSize.toString()
      );
      
    const selection = await CoinSelection.randomImprove(
      utxos,
      outputs,
      20,
      //protocolParameters.minUtxo.to_str()
    );

    const inputs = selection.input;

    const txBuilder = S.TransactionBuilder.new(
      protocolParameters.linearFee,
      protocolParameters.minUtxo,
      protocolParameters.poolDeposit,
      protocolParameters.keyDeposit,
      protocolParameters.maxValSize, 
      protocolParameters.maxTxSize
    );

   for (let i = 0; i < inputs.length; i++) {
       const utxo = inputs[i];
         txBuilder.add_input(
         utxo.output().address(),
         utxo.input(),
         utxo.output().amount()
      );
     }


    txBuilder.add_output(output);
    txBuilder.set_ttl(410021);

    txBuilder.add_change_if_needed(
        S.Address.from_bech32(paymentAddr)
      );
    

There is no error and the transaction is send and can be signed.
If someone can help me thanks

[vsubhuman]

Hi, @YFrendo ! Test version 10.0.0-beta.5 plz, when you have a chance, there's already a fix included there that improves the change-calculation performance. Note that there are breaking API changes and you gonna need to update how you create the transaction-builder, see example here:

https://github.com/Emurgo/yoroi-frontend/blob/f1affc9f90efdce2c5b7078b80a3add97d9499a3/packages/yoroi-extension/app/api/ada/lib/cardanoCrypto/rustLoader.js#L85-L95

https://github.com/Emurgo/yoroi-frontend/pull/2530/files#diff-ed6bb4dfff2837130faf834b694396f7fa1d92580769f858c53308df8fd6419dR85-R94

[YFrendo]

HI! Thanks for your answer I will probably wait for the 10.0.0 official release!
Thanks for your work and good luck!

[rooooooooob]

@YFrendo just to confirm, you're using the asm.js not the wasm builds right? I believe the fix (#214) @vsubhuman is talking about was mostly an issue in how absurdly slow the cryptography crates we depend on can be when compiled to asm.js. I would highly recommend wasm over the asm.js if its possible for you as in general wasm is just so much faster than asm.js.

[YFrendo]

Hy!
Yeah I can confirm I'm using the asm.js I will try with general wasm but not sure if I can.
Thanks for your awnser !

[YFrendo]

Hy @rooooooooob !
I tried to use the wasm version but I can't import it inside a navigator: Failed to load module script: The server responded with a non-JavaScript MIME type of "application/wasm". Strict MIME type checking is enforced for module scripts per HTML spec.
I found on internet that I need to import it in a another way but I need to change the most part of the script (to much work) do you have a solution for this ? https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/Module/imports

[josemmrocha]

I also have this exact problem. Using asm.js is too slow to have it in production, and using wasm (browser), returns the same error: Failed to load module script: The server responded with a non-JavaScript MIME type of "application/wasm".

In my case I am trying to use it in an Angular SPA.

[alice1989123]

I am using Next.JS 12 I had the same Issue with pure JS-version, then i changed to browser version and the problem was solved.

[CyberCyclone]

@YFrendo just to confirm, you're using the asm.js not the wasm builds right? I believe the fix (#214) @vsubhuman is talking about was mostly an issue in how absurdly slow the cryptography crates we depend on can be when compiled to asm.js. I would highly recommend wasm over the asm.js if its possible for you as in general wasm is just so much faster than asm.js.

Based on this does v10 have no performance improvement for asm? I'm using MeteorJS and at this point they seem to have no interest in supporting wasm.

[rooooooooob]

The performance has been improved further via #286 which should help the asm.js situation a bit. Any signing done will still be incredibly slow via asm.js though unfortunately but the building of the initial tx should be better. That PR will be included in the release of 10.0.0.

edit: I guess this isn't that bad if you're just using it with CIP-30 and the wallet will be doing the signing.