Merge branch 'master' into lighthouse-252

This commit is contained in:
thojest 2019-03-03 14:01:57 +01:00
commit 0b24a47b53
4 changed files with 25 additions and 26 deletions

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@ -8,7 +8,6 @@ edition = "2018"
db = { path = "../../beacon_node/db" }
ssz = { path = "../utils/ssz" }
types = { path = "../types" }
fast-math = "0.1.1"
log = "0.4.6"
bit-vec = "0.5.0"

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@ -1,5 +1,5 @@
//! The optimised bitwise LMD-GHOST fork choice rule.
extern crate bit_vec;
extern crate fast_math;
use crate::{ForkChoice, ForkChoiceError};
use bit_vec::BitVec;
@ -7,7 +7,6 @@ use db::{
stores::{BeaconBlockStore, BeaconStateStore},
ClientDB,
};
use fast_math::log2_raw;
use log::{debug, trace};
use std::collections::HashMap;
use std::sync::Arc;
@ -19,33 +18,28 @@ use types::{
//TODO: Pruning - Children
//TODO: Handle Syncing
/// The optimised bitwise LMD-GHOST fork choice rule.
/// NOTE: This uses u32 to represent difference between block heights. Thus this is only
/// applicable for block height differences in the range of a u32.
/// This can potentially be parallelized in some parts.
// we use fast log2, a log2 lookup table is implemented in Vitaliks code, potentially do
// the comparison. Log2_raw takes 2ns according to the documentation.
// NOTE: This uses u32 to represent difference between block heights. Thus this is only
// applicable for block height differences in the range of a u32.
// This can potentially be parallelized in some parts.
/// Compute the base-2 logarithm of an integer, floored (rounded down)
#[inline]
fn log2_int(x: u32) -> u32 {
fn log2_int(x: u64) -> u32 {
if x == 0 {
return 0;
}
assert!(
x <= std::f32::MAX as u32,
"Height too large for fast log in bitwise fork choice"
);
log2_raw(x as f32) as u32
63 - x.leading_zeros()
}
fn power_of_2_below(x: u32) -> u32 {
2u32.pow(log2_int(x))
fn power_of_2_below(x: u64) -> u64 {
2u64.pow(log2_int(x))
}
/// Stores the necessary data structures to run the optimised bitwise lmd ghost algorithm.
pub struct BitwiseLMDGhost<T: ClientDB + Sized> {
/// A cache of known ancestors at given heights for a specific block.
//TODO: Consider FnvHashMap
cache: HashMap<CacheKey<u32>, Hash256>,
cache: HashMap<CacheKey<u64>, Hash256>,
/// Log lookup table for blocks to their ancestors.
//TODO: Verify we only want/need a size 16 log lookup
ancestors: Vec<HashMap<Hash256, Hash256>>,
@ -147,7 +141,7 @@ where
}
}
// check if the result is stored in our cache
let cache_key = CacheKey::new(&block_hash, target_height.as_u32());
let cache_key = CacheKey::new(&block_hash, target_height.as_u64());
if let Some(ancestor) = self.cache.get(&cache_key) {
return Some(*ancestor);
}
@ -155,7 +149,7 @@ where
// not in the cache recursively search for ancestors using a log-lookup
if let Some(ancestor) = {
let ancestor_lookup = self.ancestors
[log2_int((block_height - target_height - 1u64).as_u32()) as usize]
[log2_int((block_height - target_height - 1u64).as_u64()) as usize]
.get(&block_hash)
//TODO: Panic if we can't lookup and fork choice fails
.expect("All blocks should be added to the ancestor log lookup table");
@ -380,7 +374,7 @@ impl<T: ClientDB + Sized> ForkChoice for BitwiseLMDGhost<T> {
// logarithmic lookup blocks to see if there are obvious winners, if so,
// progress to the next iteration.
let mut step =
power_of_2_below(self.max_known_height.saturating_sub(block_height).as_u32()) / 2;
power_of_2_below(self.max_known_height.saturating_sub(block_height).as_u64()) / 2;
while step > 0 {
trace!("Current Step: {}", step);
if let Some(clear_winner) = self.get_clear_winner(
@ -469,7 +463,6 @@ mod tests {
#[test]
pub fn test_power_of_2_below() {
println!("{:?}", std::f32::MAX);
assert_eq!(power_of_2_below(4), 4);
assert_eq!(power_of_2_below(5), 4);
assert_eq!(power_of_2_below(7), 4);
@ -478,4 +471,12 @@ mod tests {
assert_eq!(power_of_2_below(33), 32);
assert_eq!(power_of_2_below(63), 32);
}
#[test]
pub fn test_power_of_2_below_large() {
let pow: u64 = 1 << 24;
for x in (pow - 20)..(pow + 20) {
assert!(power_of_2_below(x) <= x, "{}", x);
}
}
}

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@ -13,7 +13,6 @@ use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Rem, Sub, SubAssi
pub struct SlotHeight(u64);
impl_common!(SlotHeight);
impl_into_u32!(SlotHeight); // SlotHeight can be converted to u32
impl SlotHeight {
pub fn new(slot: u64) -> SlotHeight {

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@ -147,12 +147,12 @@ pub fn ssz_tree_hash_derive(input: TokenStream) -> TokenStream {
let output = quote! {
impl ssz::TreeHash for #name {
fn hash_tree_root_internal(&self) -> Vec<u8> {
let mut result: Vec<u8> = vec![];
let mut list: Vec<Vec<u8>> = Vec::new();
#(
result.append(&mut self.#field_idents.hash_tree_root_internal());
list.push(self.#field_idents.hash_tree_root_internal());
)*
ssz::hash(&result)
ssz::merkle_hash(&mut list)
}
}
};