lighthouse-pulse/consensus/cached_tree_hash/src/lib.rs
Michael Sproul 84e6d71950 Tree hash caching and optimisations for Altair (#2459)
## Proposed Changes

Remove the remaining Altair `FIXME`s from consensus land.

1. Implement tree hash caching for the participation lists. This required some light type manipulation, including removing the `TreeHash` bound from `CachedTreeHash` which was purely descriptive.
2. Plumb the proposer index through Altair attestation processing, to avoid calculating it for _every_ attestation (potentially 128ms on large networks). This duplicates some work from #2431, but with the aim of getting it in sooner, particularly for the Altair devnets.
3. Removes two FIXMEs related to `superstruct` and cloning, which are unlikely to be particularly detrimental and will be tracked here instead: https://github.com/sigp/superstruct/issues/5
2021-07-23 00:23:53 +00:00

47 lines
1.4 KiB
Rust

mod cache;
mod cache_arena;
mod impls;
#[cfg(test)]
mod test;
use smallvec::SmallVec;
type SmallVec8<T> = SmallVec<[T; 8]>;
pub type CacheArena = cache_arena::CacheArena<Hash256>;
pub use crate::cache::TreeHashCache;
pub use crate::impls::int_log;
use ethereum_types::H256 as Hash256;
#[derive(Debug, PartialEq, Clone)]
pub enum Error {
/// Attempting to provide more than 2^depth leaves to a Merkle tree is disallowed.
TooManyLeaves,
/// Shrinking a Merkle tree cache by providing it with less leaves than it currently has is
/// disallowed (for simplicity).
CannotShrink,
/// Cache is inconsistent with the list of dirty indices provided.
CacheInconsistent,
CacheArenaError(cache_arena::Error),
/// Unable to find left index in Merkle tree.
MissingLeftIdx(usize),
}
impl From<cache_arena::Error> for Error {
fn from(e: cache_arena::Error) -> Error {
Error::CacheArenaError(e)
}
}
/// Trait for types which can make use of a cache to accelerate calculation of their tree hash root.
pub trait CachedTreeHash<Cache> {
/// Create a new cache appropriate for use with values of this type.
fn new_tree_hash_cache(&self, arena: &mut CacheArena) -> Cache;
/// Update the cache and use it to compute the tree hash root for `self`.
fn recalculate_tree_hash_root(
&self,
arena: &mut CacheArena,
cache: &mut Cache,
) -> Result<Hash256, Error>;
}