Add gas overhead per word to wrapper

[leeyikjiun]

• Change uint256[] memory randomWords to uint256[] calldata randomWords as calldata is cheaper. (around 200 to 300 less gas from forge test)
• Add wrapper gas overhead per word and coordinator gas overhead per word to wrapper.

Currently the wrapper overheads are a fix cost so it doesn't matter if you are requesting 0 word, 1 word, or a maximum of 255 words; they cost the same.

The wrapper gas overhead per word isn't that much and is mostly attributed to just copying the randomWords array around. Rough estimation works out to be around 7 gas per word.

The coordinator gas overhead per word is much more expensive and works out to be around 440 gas per word. Other than copying around the randomWords array, there's actual work done in generating the random word.

for (uint256 i = 0; i < numWords; ++i) {
  randomWords[i] = uint256(keccak256(abi.encode(randomness, i)));
}

This 440 gas per word (calculated by making a transaction with 0 num words, a transaction with 255 num words, take the difference and divide by 255) isn't too implausible as well because a quick forge test calculates that line to be around 232 to 235 gas.

for (uint256 i = 0; i < numWords; ++i) {
  uint256 start = gasleft();
  randomWords[i] = uint256(keccak256(abi.encode(randomness, i)));
  uint256 end = gasleft();
  console.log("gas used: ", start - end);
}

Whereas the gas used before and after the loop works out to be around 333 gas per loop

uint256 start = gasleft();
for (uint256 i = 0; i < numWords; ++i) {
  randomWords[i] = uint256(keccak256(abi.encode(randomness, i)));
}
uint256 end = gasleft();
console.log("gas used: ", start - end);

[github-actions]

I see you updated files related to core. Please run pnpm changeset in the root directory to add a changeset.

[github-actions]

I see you updated files related to contracts. Please run pnpm changeset in the contracts directory to add a changeset.

[jinhoonbang]

if this is only 7 gas units per word, we probably don't need it right? we can just add some extra buffer to s_wrapperGasOverhead.

[leeyikjiun]

Sure, if my calculation is correct and the overhead is that small then we can just add some buffer for it. It's at most 2.5k more gas if it's 10 gas per word. I'll need to run more transactions.

[RensR]

Please run git checkout v1.8.1 in the foundry dependency folder to undo the dependency downgrade

[cl-sonarqube-production]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

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