gnosis/lighthouse
1
0
Fork 0
mirror of https://github.com/sigp/lighthouse.git synced 2026-03-20 13:24:44 +00:00
Code Issues Packages Projects Releases Wiki Activity

Use SmallVec for TreeHash packed encoding (#3581)

Browse Source 
## Issue Addressed

NA

## Proposed Changes

I've noticed that our block hashing times increase significantly after the merge. I did some flamegraph-ing and noticed that we're allocating a `Vec` for each byte of each execution payload transaction. This seems like unnecessary work and a bit of a fragmentation risk.

This PR switches to `SmallVec<[u8; 32]>` for the packed encoding of `TreeHash`. I believe this is a nice simple optimisation with no downside.

### Benchmarking

These numbers were computed using #3580 on my desktop (i7 hex-core). You can see a bit of noise in the numbers, that's probably just my computer doing other things. Generally I found this change takes the time from 10-11ms to 8-9ms. I can also see all the allocations disappear from flamegraph.

This is the block being benchmarked: https://beaconcha.in/slot/4704236

#### Before

```
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 980: 10.553003ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 981: 10.563737ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 982: 10.646352ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 983: 10.628532ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 984: 10.552112ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 985: 10.587778ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 986: 10.640526ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 987: 10.587243ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 988: 10.554748ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 989: 10.551111ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 990: 11.559031ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 991: 11.944827ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 992: 10.554308ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 993: 11.043397ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 994: 11.043315ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 995: 11.207711ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 996: 11.056246ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 997: 11.049706ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 998: 11.432449ms
[2022-09-15T21:44:19Z INFO  lcli::block_root] Run 999: 11.149617ms
```

#### After

```
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 980: 14.011653ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 981: 8.925314ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 982: 8.849563ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 983: 8.893689ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 984: 8.902964ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 985: 8.942067ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 986: 8.907088ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 987: 9.346101ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 988: 8.96142ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 989: 9.366437ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 990: 9.809334ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 991: 9.541561ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 992: 11.143518ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 993: 10.821181ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 994: 9.855973ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 995: 10.941006ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 996: 9.596155ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 997: 9.121739ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 998: 9.090019ms
[2022-09-15T21:41:49Z INFO  lcli::block_root] Run 999: 9.071885ms
```

## Additional Info

Please provide any additional information. For example, future considerations
or information useful for reviewers.
This commit is contained in:
Paul Hauner
2022-09-16 08:54:06 +00:00
parent bde3c168e2
commit b0b606dabe
15 changed files with 44 additions and 41 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
consensus/tree_hash/src/impls.rs
View File

@@ -14,8 +14,8 @@ macro_rules! impl_for_bitsize {
TreeHashType::Basic
}
fn tree_hash_packed_encoding(&self) -> Vec<u8> {
self.to_le_bytes().to_vec()
fn tree_hash_packed_encoding(&self) -> PackedEncoding {
PackedEncoding::from_slice(&self.to_le_bytes())
}
fn tree_hash_packing_factor() -> usize {
@@ -41,7 +41,7 @@ impl TreeHash for bool {
TreeHashType::Basic
}
fn tree_hash_packed_encoding(&self) -> Vec<u8> {
fn tree_hash_packed_encoding(&self) -> PackedEncoding {
(*self as u8).tree_hash_packed_encoding()
}
@@ -62,7 +62,7 @@ macro_rules! impl_for_lt_32byte_u8_array {
TreeHashType::Vector
}
fn tree_hash_packed_encoding(&self) -> Vec<u8> {
fn tree_hash_packed_encoding(&self) -> PackedEncoding {
unreachable!("bytesN should never be packed.")
}
@@ -87,10 +87,10 @@ impl TreeHash for U128 {
TreeHashType::Basic
}
fn tree_hash_packed_encoding(&self) -> Vec<u8> {
let mut result = vec![0; 16];
fn tree_hash_packed_encoding(&self) -> PackedEncoding {
let mut result = [0; 16];
self.to_little_endian(&mut result);
result
PackedEncoding::from_slice(&result)
}
fn tree_hash_packing_factor() -> usize {
@@ -109,10 +109,10 @@ impl TreeHash for U256 {
TreeHashType::Basic
}
fn tree_hash_packed_encoding(&self) -> Vec<u8> {
let mut result = vec![0; 32];
fn tree_hash_packed_encoding(&self) -> PackedEncoding {
let mut result = [0; 32];
self.to_little_endian(&mut result);
result
PackedEncoding::from_slice(&result)
}
fn tree_hash_packing_factor() -> usize {
@@ -131,10 +131,10 @@ impl TreeHash for H160 {
TreeHashType::Vector
}
fn tree_hash_packed_encoding(&self) -> Vec<u8> {
let mut result = vec![0; 32];
fn tree_hash_packed_encoding(&self) -> PackedEncoding {
let mut result = [0; 32];
result[0..20].copy_from_slice(self.as_bytes());
result
PackedEncoding::from_slice(&result)
}
fn tree_hash_packing_factor() -> usize {
@@ -153,8 +153,8 @@ impl TreeHash for H256 {
TreeHashType::Vector
}
fn tree_hash_packed_encoding(&self) -> Vec<u8> {
self.as_bytes().to_vec()
fn tree_hash_packed_encoding(&self) -> PackedEncoding {
PackedEncoding::from_slice(self.as_bytes())
}
fn tree_hash_packing_factor() -> usize {