What is the compute cost for calling the native Ed25519 signature verification program?

Question

I'm trying to measure the compute unit cost for my transaction which has 2 instructions:

{
  ix0: native ed25519 sig verify (Ed25519SigVerify111111111111111111111111111)
  ix1: myprogram.foobar
}

but on my local machine the reported amount from solana logs only has numbers for myprogram.foobar. No mention of the native ed25519 program.

Transaction executed in slot 62:
  Signature: qPGf7Trp9KnRCfBVphsckxdE9M5PwLdcNGbjHbBu46r4m7jCvhPRYkctBVL2RnHX4GbKaJJTHza9348WF4gtRnq
  Status: Ok
  Log Messages:
    Program BJpP8hHbVz5uoSqDM1CBjc2GoQnayssyZvYe7qLoaA49 invoke [1]
    Program log: Instruction: myprogram.foobar
    Program BJpP8hHbVz5uoSqDM1CBjc2GoQnayssyZvYe7qLoaA49 consumed 21997 of 400000 compute units
    Program BJpP8hHbVz5uoSqDM1CBjc2GoQnayssyZvYe7qLoaA49 success

Is there a compute cost for the ed25519 instruction that counts towards the 1.4m total tx compute budget? And what is the lamport SOL cost for the ed25519 instruction?

Answer 1

The ED25519 program is a bit special, since it doesn't require any accounts to be loaded or modified. It's run as a "precompile" during transaction sanitization: https://github.com/solana-labs/solana/blob/b5b48eeb72a1824b0d48f1cca3ba59b518932153/sdk/src/transaction/sanitized.rs#L272

As for the compute cost, this took me awhile to dig through, but it looks like it only has a lamport cost, as reported through SanitizedMessage::num_signatures https://github.com/solana-labs/solana/blob/b5b48eeb72a1824b0d48f1cca3ba59b518932153/sdk/program/src/message/sanitized.rs#L354-L357

This way, the instruction signature is treated the same as any other signature in your transaction.