optimize mload instruction to not allocate a temporary vector #4
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@birchmd not sure what's the right workflow here to land the changes. |
olonho
reviewed
Feb 9, 2022
core/src/memory.rs
Outdated
| @@ -96,6 +96,23 @@ impl Memory { | |||
| ret | |||
| } | |||
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| /// Get `H256` from a specific offset in memory. | |||
| pub fn get_h265(&self, offset: usize) -> H256 { | |||
olonho
reviewed
Feb 9, 2022
| pub fn get_h265(&self, offset: usize) -> H256 { | ||
| let mut ret = [0; 32]; | ||
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| #[allow(clippy::needless_range_loop)] |
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Maybe we could better do smth like
pub fn get_h256(&self, offset: usize) -> H256 {
if offset + 32 < self.data.len() {
H256(self.data.as_slice()[offset..offset + 32] as [u8;32])
} else {
H256::from_slice(&self.get(index, 32));
}
}
This looks like a pretty simple change, should be easy to get it reviewed and merged if we make a PR against the upstream https://github.com/rust-blockchain/evm |
Naked-eye based optimization -- it feels suboptimal to allocate a `Vec` to fetch `[0; u32]`. Running a macro-benchmark in aurora shows that this is about a 1% win, so the compiler probably can't eliminate this vec entirely.
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submitted upstream rust-ethereum#97 |
aleksuss
added a commit
to aleksuss/sputnikvm
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Jul 2, 2024
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Naked-eye based optimization -- it feels suboptimal to allocate a
Vecto fetch
[0; u32]. Running uniswap bench in aurora shows that this isan 1% improvement in wasm cost, so the compiler probably can't eliminate
this vec entirely.